Hey guys, just wanted to say that the reason for the bouncing up and down is due to the change in leverage. Since one of the wheels is further back it has more mechanical advantage over the suspension due to the increased distance of the swingarm
thank you for making this comment for someone who works on motorcycles this much im very surprised he had no idea why it was doing this its about the most simple explanation ever
Hey guys, self appointed B&B R&D Engineer here: I think part of the issue is the transition of one tire to the other. Perhaps in the example videos, their design wasn't a precisely half of a wheel but instead 60% (or something) so that both tires would have larger contact with pavement during transition. Right now with tires being 50% there's only the ends of the tire touching pavement and essentially squishing because there isn't the same distribution of weight as say the centre of the half tire compared to the end of a half tire. So perhaps the solution is to make the tire completely solid somehow so it doesn't squish and create a hop; that or a combination of cutting the wheel at 60%. BUT WAIT, there's more, MAYBE the suspension itself is an added obstacle and simply making it a hard tail like a road bicycle would remove the need to work around the suspension.
on the bounce. the longer the frame, the more sag you have in in. your frame is going from 5 ft to 6 ft and back again, constantly. not to mention the tips of the tires aren't properly supported and so will bend more than the uncut middle adding even more bounce and reducing the time you have before the tire overheats from flexing.
the suspension is engineered for a specific swing arm length, when you transition to the half wheel in the farthest back the swing arm is basically longer and the lever effect on the suspension is greater, so it compresses more and so on.
Absolutely. Can't understand why these guys didn't see it. It's really obvious.. Having said that, I can't think of the cure.. you'll have to constantly change the suspension mounting point, or perhaps removing the suspension altogether. Making it a hardtail, Harley style??
This was amazing! The bumpiness is due to the two wheels exert different leverages on the swingarm due to different distances from the fulcrum (point of rotation). Thus the spring compresses more when the weight of the bike is on the wheel that is farther away from the fulcrum, and less when the weight is on the closer wheel.
exactly. one wheel has a longer "arm" or moment, allowing the bike to compress the spring more. do this on a bike with no rear suspension and you shouldnt have an issue
this is what I was thinking too, they even mentioned that it might be a problem in the video but I think they misunderstood how it would manifest when riding it
Instead of cutting the tires where you want them leave a bit more rubber on each end then bend that piece back so the loss of contact with the ground is more gradual. Also suspension to the end would keep it in contact better. Excellent video
yeah, i was thinking, if it is suspension, then bring some arms up to the back of the seat with shocks, also, maybe cut the tires by a bit less than half, so they both are in contact at each end
I thought about what would happen, I was thinking he could mount them on both side of the outer rin, that way they would/could safely wheelie Edit, they already did that and It wouldn't work :/
The suspension will compress more when the weight is being suspended on the different axles. It's like holding a weight close to your body and then trying to hold the same weight at arm's length. The only fix that springs to my mind is to in some way have the 2 rear wheels have independent suspension. That way, you can adjust each to compensate for the differing load.
or mount the rear tire on a slightly downward facing angle, so when the rear comes in contact with ground and the suspension compresses, the travel is compensated
You get more leverage to compress the spring when it's riding on the rear wheel, kinda like when you're closing pliers, then it's easier to do when you're clamping on the end of the handle. You could get rid of most of it by simply just riding without a spring and welding the whole thing so it doesn't have any suspension travel, or you could stiffen the spring. Also, as another commenter said, you should have 55-60% of the tire left, so you get a smoother transition.
spot on man. I was thinking you put it on a chopper since they don't have suspension usually anyways. I didn't think of the 55-60% of the tire left, but that would probably help a lot too
100% correct, torque is a matter of force multiplied by distance, the further away the centre of the wheel is from the spring (rear-rear wheel is further than rear-front wheel) it will increase the amount of torque the being applying to the shock mount, therefor compressing the spring more on the rear wheel causing that bump effect. the only way to completely eliminate this effect is by not cutting the wheels in half (no point in the video), welding/removing the shock (resulting in a bad ride) or have a hydraulic spring, changing the compression force to suit the torque each wheel is producing to the spring (extremely complicated - if its even possible) if you were to have 55-60% of the wheel, it will make the torque transition smoother (correct again) but it will still have the same peak applied torque when there is just 1 wheel on the ground, which will only be noticeable at low speeds. at higher speeds, the slight extra length in circumference will become negligible
That is truly remarkable. You have managed to bring back the galloping effect of riding a horse while achieving the speed of a modern motorcycle. I am impressed. 🙃 LOL. If you can market this you will reach two markets at the same time....The Equestrian community and the Motor Sports community. The real challenge is to make it look and feel like a horse on one half and a modern motorcycle on the other half. I'll leave it to you to decide which half to change. Respect. Keep doing what you do. It is a lot of fun to follow along. God Bless
Use 60% (as others said) and the hardest solid tires you can find (like indoor forklift tires), your bumpyness will diminish some. It's bouncing because of the different leverage the different lengths of swingarm have on the spring as the weight changes from tire to tire. The weight of the wheels is also changing back and forth between sprung and unsprung weight at different points on the swingarm/lever. Also..., the front tire becomes additional weight while off the ground but the rear becomes a counter weight while off the ground. In other words the weight felt by the spring is changing.
Came here to say this. You can even see as the forward tyre makes contact with the ground the bike lifts as it's pushing against the suspension at a steeper angle, and relaxes back down as the weight goes on the rear tyre.
I should have read further before adding my comment, as you have already covered the idea. Running the tires side by side would be the only way to possibly completely eliminate the gallop. Even adding hard tires wouldn't kill it completely in it's current state as the different lengths of the armature where the wheels are attaches would react different to the centrifugal force created by the off balanced wheels. Even side by side this could be problematic since the wheels would be attached to a perpendicular axle that would cause wag instead of a gallop. The only way to make it efficient to any usable speed (for a practical lifetime for a motorcycle) would be to add a third parallel wheel and weight the rims with enough precision to stabilize the centrifugal force between the three.
@@theukdave2433 Yes ... I believe you can fix this by making one of the rear half-wheels a larger or smaller (original) diameter than the other...as to how much and which one...???? Havn't thought enough about it yet...LOL
Hey guys, this one was wild!! Haha So, I’m commenting as I watch so if you say the answer in the video I haven’t made it that far yet!! But to the dropping dilemma, the swing arm is longer and the shock is in the original spot. When on the back tire your weight is increased due to the leverage of the extended arm. Essentially when on the back tire you are much heavier. Pretty sure that’s a big part of why it’s happening!
the little extra touches in the edits are really sweetening these vids. the butter knife thing and sean flying round the workshop with pipe arms. love it
I think the reason for the bumpyness is that because of the leverage from the extended controll arm. So if you move the suspension to in between the rear tires it should get a little better, but i think the best solution is just to remove the rear suspension, it would be a harsh ride but
That is exactly what I wanted to write down here. Make the suspension much stiffer and probably will be less bumpy. But the other fact that the middle of the tire will be stiffer compared to the end point of the half will also have some effect. So this will never be a smooth ride I guess.
I think the problem is not the stiffness. The problem is that the center of both rear wheels have different vertical positions, because the holder isn’t parallel to the street. If the holder of the rear wheels would be absolutely parallel to the street it would not be bumpy.
Your rearmost wheel has to be in line with the swing arm. Youll have to find exact centre where the swing arm rotates on the frame and have it in line with that and the other wheel
The trailing edge of the front drive tire is collapsing, while the rear tire comes around with no weight on it making it taller than the other tire when it contacts the ground. They need stiffer tires or possibly there has to be a time of overlap where both tires are in contact with the ground, to get rid of the weird weight transfer
2 possible fixes. 1) Hard tail. 2) Need to move the spring. There will be a spot on the swing arm where the weight of the unloaded tire will balance the leverage difference of the loaded tire which is where the spring needs to be attached. You may have to also counter balance the wheels too but they balance each other out. It's too early for me to work that physics out lol
O believe you are onto it but and even easier fix might be to just correct the angle of the rear wheel. They also should have cut the wheels just a little bigger then half because the low point seems to be where the wheels join in the wheels are touching because they're not solid so it might be creating a flat spot. ( ) like that.
I used to engineer suspension for Ford... 1) Hard Tail. - Assuming you don't need suspension, this is the best answer. Great job, I would choose this one. 2) Move the spring. - What happens is you find that spot, then you have to manage an oscillating force on the wheel plane for the rear two tires. This would require more weight and parts to manage. Basically, making a single wheel for efficient.
@@Invincibletro do you reckon it also had to so with the face that when the wheel is full it is a circle but wheb it is cut it is no longer and circle and has a flat spot which could also help woth this. C O imaging the C was slit at the top because essentially its a circle if the middle point is removed on the jointed together side. Or do you think its specifically only suspension. I thought it was only suspension at first but I looked closely at wheb it Bobbed and it was wheb the wheels where like this ( ) as upset to while either of the wheels was on the ground.
@@bennyrest9122 When the wheels are like this ( ) this is the exact moment the length of the lever changes, When they are ( ) the lever is the distance between the closest axel and the pivot. What you might be seeing is the A arm angle does change immediately when this transfer happens, lowering the closest axel, or raising it instantly between the transfer between the two levers.
Yep, you need to change the suspension geometry so that it has a strut on the back wheel at a minimum. Otherwise, the weight will always be balanced towards the middle wheel, which means there will be a weight shift each time the wheel changes. Cool concept, though!
needs to be placed between both rear wheels otherwise the center of mass will still primarily be on the front of the rear wheels, causing the middle wheel to compress and leading to the same leveraging issue, albeit to a slightly lesser extent. You got the closest out of anyone in the comments i've seen so far though so gw. You actually could make an independent rear suspension version but it would require redistributing the weight and altering the frame and completely changing the suspension geometry etc.
Exactly this, and I'm thinking at higher speeds the centurial forces are going to put different leverage on the swing arm, that problem would also be fixed by strutting the back wheel
The reason it was bouncing was because they did not correctly extend the swing arm, the new length they added was on an entirely different axis than the bikes stock swing arm. Having a strut like what you're talking about would not do anything but likely make it worse, if the extension was able to pivot freely, sure the strut would do it's job. In the end of they 100% extended the swing arm keeping the axle points on the same axis it would be perfect.
You guys rock, pure humor along with ingenuity.. can't beat it. You really should ride into the local dealer. I need you guys to check out my bike I think something's wrong with it it's not riding smooth anymore.
Not a physics major, but I think the added length of the arm going to the backmost tire is increasing the overall torque applied to the suspension. So as it switches it compresses more
Agreed. They need to replace all of the suspension, including the front, with solid steel/aluminum. Its going to ride like crap but even if the front suspension compresses, it will cantilever the furthest back tire higher and drop down onto it so there will still be that vibration while riding. Smoothest ride will be with no suspension compressing at all.
My take on the bumpiness: There is a force difference when each half of the tire makes contact with the ground because of the lever effect. The rear-most tire half will have less downward pressure on it than the forward tire half which sits naturally almost right under the rider. The increase in wheel base might also contributes to some flex in the frame, specifically the welded on piece. Wouldn’t be surprised if it would eventually crack from exhaustion. Combined with another guy who mentioned the ends of tires being more flexible than the middle of them, this can easily create a bumpy ride. I love that it looked just like riding a galloping horse.
Yeah if anything was deserving of the "do not try at home" title this is definitely a winner! (It's much more fun to do it at work anyways ;) ) Didn't expect it to be able to start galloping like a horse LOL
Dude I could not legally agree more. This thing screams at the top of its lungs, BAD DECISION!!! Kids and everyone else for that matter, don't try this at home. These morons are actual pros at being morons. Let them hurt themselves. Then learn from their mistakes
@@slickatoe well, you'd think that's the stupidest thing in the world but today i'll have you know i scraped the ice off my gixxer thaw 2001. it was all good till i hit second and it suzuki'd all over the street.
I absolutely love these guys. Not only are they entertaining as hell, but they truly are good people and always send positive energy through their videos. I’m a Hugeee fan, and I just have to meet these guys someday. 💯👍🏼👍🏼🔥
Yes I love that they are Christian. These guys are the best. And yes I’ve worked at a motorcycle dealership for years, ppl don’t realize how much skill and work actually goes into some of these projects!
Im not sure how to solve it, but the issue with the bouncing/raising up and down is because when the REAR rear tire is on the ground there is more leverage being used to compress the suspension, but when the FRONT rear tire is down theres less leverage, causing the suspension to compress less than the other wheel does. So if theres a way to mod the suspension to be farther back it should lessen the issue. Love this video 🖤
This is the issue. the fact that one tire is further back causes the bucking issue. How you could mad this so the spring is in between the 2 forces I have no idea. (note the spring needs to be between the forces not between the tires.)
One solution would be to replace the suspension with a fixed (strong) rod. The swingarm would no longer move, but the handling might suffer a but from that....
I think besides the tires not being solid on the ends and not being 200 degrees, and not being timed perfectly, that they also need to be counterweighted (balanced) It's easy to think them being horribly out of balance is OK because they cancel each other, until you realize they arte at different moments on the swingarm so they are pumping the swingarm up and down. The frame also needs to be a rigid like the bicycle because the two wheels present different leverage points on the suspension. I say if at first you get mixed success, try, try again!
That should do a lot. Right now when the rearmost wheel has contact and the other doesn't, the lever arm is long. When the front rear wheel has contact, the lever arm is short. Shock can't compensate that kind of force difference. Get rid of the fulcrum I'd say.
18:33 Damn that was the trippiest thing I’ve ever witnessed that wasn’t a digital illusion 😂 I think if you offset the back wheel to be a little higher maybe even lower it should ride smoother.
I think strengthening the swing arm will help as any flex with the back-rear wheel contacting ground will cause the front-rear wheel to essentially be below the ground level when it returns to contacting. Also counterweighting the wheel halves should help a lot too
I was thinking that if they relocated that rear shock over the center of both wheels that it'd be easier and better for the suspension to take it in and maybe less of a rough ride.
Wow, it actually worked... Awesome!! Strengthen the extension arm, I'm sure it flexes when weight is on the back tire. Like another comment said, make it a 60% wheel instead of 50% so the transition is smoother. Fill the tires with the densest foam you can find before you rivet them. And counter balance the tire as best you can.
Think about leverage and lever length. As others have suggested, you'll need to change the suspension geometry, otherwise every time the weight transfers to the wheel with greater lever length, greater force is applied to the suspension and the swingarm will compress due to the shift in leverage.
My wife and I just lost our 3 week old baby in the NICU - I've been reading James Chapter 1 and 5, you just blew my mind with this scripture reference at a really needed time. I just randomly stumbled on your channel, or it could be said that perhaps God led me here to remind me that he hears me praying, ether way - thank you for that encouragement
Called it from the beginning. The problem with this idea is when the weight is on the back tire the suspension has more leverage on it so it compresses. When the weight transfers back to the front tire the suspension rebounds and creates the bouncing motion. The shock/load needs to be mounted between the two wheels somehow so the leverage affect is equal. Or make it a hard tail. Also making the wheels a little bit bigger than 50% say 60% will make the transition from one to the other easier.
Just my thoughts are the tire would need to be slightly more than half way in circumference to create a smoother transition from tire to tire. Right now there is a slight gap from the amount removed from the cutting in half portion , you need consider the amount removed from each (even as little as I might be. There still a gap, as well as there is no angle of entrance to help create a smooth transition from tire to tire. I think you would need to cut 2 tires part the 180deg point for a better blend. Like maybe 190-200 degs. 🤔 And maybe some counter weights???
thats not what is causing it to bounce, thats the shifting lever point on the rear arm but I agree that they shouldnt be cutting the wheels exactly in half, kinda surprised they did it that way. There should at least be a little overlap to ease the transition more
Okay, so this will work, but you have to make the wheel halves side by side so it's more stable, and won't bounce. Mounting them properly side by side will allow for seemlessness when you're riding, because they'll be mounted practically in the same spot, and not in single-file line style.
This build is sick but id like to give some input on the bouncing issue the reason it bumps is because as you transition to the farther tire the weight of the bike has more leverage on the swing arm compressing the shock more. Then when it goes back to the closer tire it has less leverage so the bike sits higher. I would like to see the shock be replaced with a metal rod at the height where both tires touch the ground as a possible solution to this. Also another reason could be that the edges of the tires are softer than the middle since there is less support due to it being open allowing the bike to sit lower from the tire squishing. maybe as someone else mentioned making the wheels with 60% diameter instead of 50% could fix this. Overall awesome build and I would love to see it revisisited because I'm confident it could be fixed to ride smoother fairly easily.
The leverage effect is exactly right. If these half tires were side by side on the same axle it would be less of a problem. Each half tire needs needs to be indepently counter weighted.
Yup, more leverage! In the bycicle video there is no suspension so it works. Having slightly more than half the tire might help the transition between them too.
I think it would be worthwhile adding some sort of counterweight to each wheel. Something close to the center. Won't be that much of an issue at low speeds, but if you go for higher speeds it'll be necessary for the wheels to be balanced
All you needed was a pivot point in between the rear wheels. Attach your rear wheels to both ends of swing arm you made and put that pivot in between the wheels and attach the bike's original swing arm, which would need extending a little, to the pivot point pin/axle, if you will. You would need a brass bushing/bearing in the pivot mount for the shaft. This is just like a tandem axle trailer is set up, as far as the pivot point. You would need a single chain, long enough to go around the two sprockets and add a small sprocket as a spring loaded chain tensioner, in between the two driving sprockets, to take care of the distance change from the engine sprocket, when the suspension moves up and down and the wheels move up and down in the pivot. Just a thought.
The rearmost of the rear wheels has more leverage against the spring (through the swing arm) than the other. This causes the bike to sit lower (as the spring is more compressed) when the weight is on that one compared to the other.
This would definitely turn heads to see this go down the road! Something that might help a little is to take the slack out of the chain between the rear wheel as there is a push then release as each wheel comes in contact with the road and releases, transferring drive torque from one to the other.
a idler sprocket should easily take the slop out of the chain.
Год назад+11
The difference of contact points makes the lever arm to compress the suspension compress more/less depending on which tire is in contact with the ground. The weight each of the "½ tires" are similar, and one have a much longer lever arm to compress the spring. The easiest solution is to remove the spring, replacing it with a solid rod, as I don't think you'll try any high speed shenanigans. There are other ways too, but waaaay more complicated :)
If you want it to be smooth, you need to extend the rear swingarm out to the center point between the two split wheels and put the split wheel assembly on a pivot at that center point. However, why stop at 2? Make it 6 split wheels, each 45deg and phased so that 60deg of wheel is on the ground at any moment.
I have been waiting for someone to put a second back wheel on a bike. Shocked it took this long! Cutting the two back wheels in half I never saw coming! Love it!
No, I think with modern tech you could make it possible to tail whip a motorcycle. It probably wouldn't be cost effective in anyway but it could be done. Also, if you bent the ends in on each side a bit more you could achieve a flush surface w/o a the bumping up and down. It's the initial contact that is causing this issue, so if you make the intro and outro curves more severe you can bypass that a bit.
The pivot point of the arm puts a load on the closer to pivot point wheel. Try lifting the rear about an inch so when you sit on the bike the weight distributes a bit more even on the tires but bumps will still be causing this hop problem Maybe like a dual axle trailer. An equalizer arm in between the wheels would balance out even through bumps I’m sure that’ll be another cool idea for another video Looking forward to more 💪🏼
The load on the suspension changes as weight moves from the closest wheel half to the rear wheel half due to the leverage on the arms. If the 2 wheel halves were side by side (like a dual wheel truck wheel) it would probably work.
here is an idea about how to solve bumping issue. There are two issues that I noticed. Leverage diffrence between both parts of the wheel and no overlapping. First you need to extend the swing arm furher but do not change distance between both parts of the back wheel, move the front part of the back wheel further back instead that way leverage diffrence between two parts of the wheel relative to front one will be significantly less. Then instead of cutting the wheels in half and having 1 whole wheel in total you'll need to cut out only 45% of the wheel so you can have two 55% wheel and one 110% of a wheel in total. That way having something extra on each half of the wheel you'll elimininate the possibility of that back wheel losing ground contact ever. even a split second loss of ground contact will result in significant bumping issue.
Bounce Baby Bounce! Haha 😂 Great job guys! Love the videos! So your bounce is because of leverage being applied to the suspension. The fulcrum point is moving back and forth with the change in drive wheel halves. If you want to keep it a softail you could put an additional spring and shock angled back from the rear of the bike, closer to the rear tire. It would need a stiffer spring rate than the existing spring to balance the compression, so some load calculations will be required. Cheers!
The hopping is coming from transition to the outer tire which adds more leverage against the suspension making it drop. Making for funny bouncy motorcycle. You guys are awesome!
@@Wreckz_Tea It will hop from the leverage changing even if they used the same exact tires, and no matter what pressure/stiffness/etc. they managed on the tires either.
Ok. This is the coolest thing ever. But I think you missed an opportunity. Two clown horns at different notes inside the tires would have put this right over the edge.
The reason it bounces is because when the back tire is on the ground, it has more torque on the swing arm which compresses the suspension more than the front tire, making it bounce when it transitions from one to another
The easiest way to fix it would be to lower the rear(-est) wheel and adjust it's shape to something resembling half an egg (to allow for the time it takes the suspension to travel). Hmm... ...maybe it's easier to make a separate suspension for that 3rd wheel, but then you need to allow that arm to move and ultimately need to extend something from the body of the bike over the 3rd wheel. There is no easy way to fix this IMO.
Hey guys, just wanted to say that the reason for the bouncing up and down is due to the change in leverage. Since one of the wheels is further back it has more mechanical advantage over the suspension due to the increased distance of the swingarm , make the back suspension in center of both tire's
(EASY FIX!) The reason your motorcycle is going up and down is because the rod (frame where your tire is connected 7:59) is not perpendicular to the ground. Your frame is inclined at a very small angle. This means the distance from the center of the rod to the ground will be more than that of the edge of the frame. Even if the size of the tire is the same, it will go up and down. On the other hand, it will work fine when two tires (not split tires) are connected because the forces are distributed. And in this condition, the tire at the edge is holding more load. There can be two ways to fix this: either the rod must be perpendicular to the ground (to do this you need two bigger tires of the same size) or when the rod is inclined, the tire at the center must be a little bigger than the last one. And I think the first option will be better.
Instead of strapping the suspension down in the back, you need to install a solid strut to keep all three tires running on a flat plane. With the change in wheel base length, you are changing the leverage that your weight has on the shock, so it changes height with each half rotation of the tires. If you remove the shock motion, you will also remove the up down motion. Just weld in a solid vertical riser on both sides where you had the ratchet straps before. If your riser is too short or too long, you will still have a bumpy ride. If you get it the right length, the ride should smooth out.
Craig does it again! ( Sean, I assume was busy doing all the behind the scenes technical stuff) I’m a bike mechanic too and I can’t get any work done because all I do is watch and rewatch you guys! God bless you guys and stay up on two…. Or three…sorta
swing arm probably needs to be bent slightly upwards after the 1st half tire to even it out. maybe even use like 52% tires instead of half tires withe the rubber capped off or rounded at the end to catch better like a fillet.
BTW: It's going up and down because the lever that puts force onto the suspension is changing length every half turn. The solution would probably be to put the hole thing at a slight downwards angle (higher at the front, lower at the back) until it's "perfect". Or just replace the rear suspension with a fixed rod...
The design looks like it would be applicable on off road and snow sections if it can switch itself from the street mode. Can't wait to see what future technology we can come up with.
Love watching videos, I don't know if I could work with people who are this overall positive about life though it might rub off. Keep up the good work.
The rear tyre has longer leverage on the swing arm so it's compressing the suspension more for the same weight. So maybe replacing the rear coil spring with just a metal tube would fix that. You won't have rear suspension anymore but that's "not an issue" on choppers so it'll propably be fine?
exactly, and since the furthest rear axle is above the pivot point of the arm, the wheel closest to the body of the bike is actually lower down and closer to the ground so its just pushing itself back to fully leveled, thus creating the shake
My Scottish engineering solution to the bounce problem is to fit a pivot point on the new swing arm, each side, in-between the 2 rear wheels to give the rear wheel a little independent movement vertical. You could possibly force the rear wheel to stay on the ground using a set of small dampeners or springs on each side, to keep it pressed against the road surface too! 🤔👍
My indigenous engineering also came up with the same deductive conclusion & possibly using tires & rims just alittle longer than half a rim & tire.😳🤔👍🤣
That Scottish idea won't work, as the 2nd swingarm will drop down towards the wheel that isn't touching the ground. Easiest solution is to fix the rear shock, so that the swingarm extension piece is always parallel to the ground. Also the front suspension should be fixed, because it has the same change of leverage problem.
@@fritsified5952 The pivot would have a block to prevent the extended swingarm from dropping past the range of the primary swingarm, allowing for compression but not over-extension of the extended swingarm. The front swingarm would have to be limited on over-extension too
@@TheReal10bears If you prevent both sides of the seesaw swingarm to drop it's the same thing as being fixed right? Anyway, you'll still have the issue being the distance between the contact point with the ground and the original swingarm pivot that keeps changing.
I think its the "leverage effect" that makes it bounce.. cause the leverage length changes when it touches the ground on the different tires. Really great video anyway :D
That does not happen on the bicycle. What causes it on the motorcycle is the rear suspension varying the angle of the swingarm based on the rider weight.
Have you considered adding weight on the other side of each tire to balance it? Right now you have two off-set wheels throwing torque all around and definitely adding to your shake issue.
nah i don't think it works like that. my guess would be because of the suspensions, was reading some comments and saw someone says there were 2 different leverages, i think it's because of the further wheel not being close made the bike and rider heavier rather than the wheel closer thus makes the bike bounce when moving ( does that makes sense? ), it didn't make some bounce action on the bicycle video because it had none.
19:20 Note for why it's bouncing: Due to one wheel being further back and there only being two wheels it has a sorta situation like a lever, especially noteworthy due to the curvature of the earth making it more notable because the closer tire will be higher up, pushing up against the ground.
"especially noteworthy due to the curvature of the earth making it more notable because the closer tire will be higher up, pushing up against the ground." lol
You guys must be fun 😊 to work with. I like how you come up with your ideas on this bike, it's so freaking outside the box 🎁. I hope you don't change, this world needs more people like you guys. Your like the Nickolai Tesla of the
Lots of fun watching you guys! Got my laughs in. Like other's commented, I think 60% tires would be better and maybe some way to make them solid rubber tires.
1. The swing arm extension is acting like a cantilever causing bending due to the support from the suspension being placed so far from the 2nd sprocket. 2. When the load from the bike shifts from the first tyre to the second tyre, it causes a massive jump in the radius of the moment torque in the swing arm, causing the force at the suspension to go up and down, which in turn increases the bouncing caused by the bending in the swing arm. The only way to deal with this is to introduce another suspension system onto the second sprocket, which should be an equivalent mass system of the entire first suspension system, so they work exactly the same.
You should be able to fix the bouncing by welding a support trust the the frame under the seat. The back wheel is twice the distance from the shock so it has twice the leverage and need half the force to compress your suspension
Weld the back suspension up is probably the simplest idea, the support truss would only strengthen the back end from falling apart during vibration it wont stop the bumping due to leverage on the suspension. They need to either weld the back suspension up, or change it to an old style dual shock where is connects to the vey back axle, going to be a bumpy ride either way.
That's what I was thinking when the suspension compresses it lightens the load on the farthest wheel! Putting that long arm up in the air sort of? All-in-all at least it was! LOL Kind of surprising?
Add a counterweight to each wheel opposite the tire side. Edit: if your rear suspension is designed to perform at different angles relative to the frame this will never work. The middle wheel will be closer to the ground under heavy load and the rear wheel closer under light loads. This is because the center of the suspension should be between the wheels, not completely outside of their balance.
A simple fix would be to angle the new bar attaching the second tire slightly towards the ground. Thus the increase force created by the longer swing arm when the second tire hits is counter acted with reduced height from the pavement. Would need to be angled differently for each people of differing weights. Great video. Hope my explanation made sense. Though I'm sure someone has already mentioned it and better, in the 6k plus comments! DC
On general, guys, The best way for how to prevent speed wobbles on motorcycle before you ever leave home is to do regular bike maintenance. Frequently check components of your bike such as its suspension, aerodynamics, steering damping, and wheels, especially if you purchase used motorcycles.
I would make that a triangle with the bars going up towards the seat but with suspension to the seat. Also pretty sure you don't have enough tire. The transition could use a bit of overlap.
The physics behind as to why you're bike is bumping up and down is bc your center of mass on the middle tire (the first back tire) is catching your weight every time you move from the rear tire to the middle tire, and since the bar is holding the rear tire from going down, it's actually on a wide obtuse angle (think of it as a really long, wide V). One way to fix this is to remove the suspension, but that is a pretty hefty takeaway from safety as you'll have to be really careful on the road. Another way, which I think is safer, is to make the bar holding the rear tire adjust 2-5 degrees depending on how much the bike moves down when transitioning from the rear to the middle tire. This way it'll make a smoother transition from the middle to the rear and vice versa bc there isn't anything holding the rear tire up and the middle tire is in contact with the ground. The only problem with this would be the rear rubber of the tire might not be the first to contact the ground, but rather the rim, but I think that can be fixed if you roll the ends of the rubber over the ends of the rim, kind of like when your bottom lip covers the upper lip. Hopefully this helps.
Yeah, the rear tire has much more leverage against the suspension, causing it to collapse, while the "middle" tire then lifts it back up, because it has less leverage on the suspension. Would have to make the suspension all Solid (no suspension) for it to go away... but even then it might have considerable leverage against the frame to break it. (and on top of that, the force of the unbalanced tires).
Hey guys, just wanted to say that the reason for the bouncing up and down is due to the change in leverage. Since one of the wheels is further back it has more mechanical advantage over the suspension due to the increased distance of the swingarm
thank you for making this comment for someone who works on motorcycles this much im very surprised he had no idea why it was doing this its about the most simple explanation ever
It was such a simple conclusion, I was almost yelling at the video saying “you have two different leverage points, one hard, one softer”.
Yep... Old Archimedes could have told him what was wrong and he'd never seen a motorcycle.
They even mentioned how the wheel base would change constantly
Completely off base comment above with 3.5k likes. Actual explanation of the problem, 33 likes. GJ people
Hey guys, self appointed B&B R&D Engineer here: I think part of the issue is the transition of one tire to the other. Perhaps in the example videos, their design wasn't a precisely half of a wheel but instead 60% (or something) so that both tires would have larger contact with pavement during transition. Right now with tires being 50% there's only the ends of the tire touching pavement and essentially squishing because there isn't the same distribution of weight as say the centre of the half tire compared to the end of a half tire. So perhaps the solution is to make the tire completely solid somehow so it doesn't squish and create a hop; that or a combination of cutting the wheel at 60%. BUT WAIT, there's more, MAYBE the suspension itself is an added obstacle and simply making it a hard tail like a road bicycle would remove the need to work around the suspension.
This makes a lot of sense
I also think the space between both back wheels is negative, basically making a longer wheel
Problem is suspension when the point of weight changes
i know how to do it better, don’t😂
The 60% wheel idea ... 4 good motorcycles into one bad motorcycle.
Sounds twice as good! :)
just wanted to say that the most posible reason for the bouncing is due to lack of Blinker Fluid, very common on those bikes 👌
Yep
It's a dealer secret, they never tell you that!!
oh yeah yeah
No, it’s because one tire is bigger than the other.
oh yeah yeah
on the bounce. the longer the frame, the more sag you have in in. your frame is going from 5 ft to 6 ft and back again, constantly. not to mention the tips of the tires aren't properly supported and so will bend more than the uncut middle adding even more bounce and reducing the time you have before the tire overheats from flexing.
the suspension is engineered for a specific swing arm length, when you transition to the half wheel in the farthest back the swing arm is basically longer and the lever effect on the suspension is greater, so it compresses more and so on.
Hard to digest at first, but after you said lever effect, suddenly I can imagine that easily. Nice explanation.
Absolutely. Can't understand why these guys didn't see it. It's really obvious.. Having said that, I can't think of the cure.. you'll have to constantly change the suspension mounting point, or perhaps removing the suspension altogether.
Making it a hardtail, Harley style??
Fix would be to somehow have the suspension attach between the wheels so each wheel is same distance from the pivot.
The solution would also be to replace the suspension with rigid steel beams.
69th like
This was amazing! The bumpiness is due to the two wheels exert different leverages on the swingarm due to different distances from the fulcrum (point of rotation). Thus the spring compresses more when the weight of the bike is on the wheel that is farther away from the fulcrum, and less when the weight is on the closer wheel.
exactly. one wheel has a longer "arm" or moment, allowing the bike to compress the spring more. do this on a bike with no rear suspension and you shouldnt have an issue
this is what I was thinking too, they even mentioned that it might be a problem in the video but I think they misunderstood how it would manifest when riding it
My thought as as well.
THIS !!!!
I was hoping someone would of pointed this out in the comments
Instead of cutting the tires where you want them leave a bit more rubber on each end then bend that piece back so the loss of contact with the ground is more gradual. Also suspension to the end would keep it in contact better. Excellent video
Needs another set of tires to balance wieght
yeah, i was thinking, if it is suspension, then bring some arms up to the back of the seat with shocks, also, maybe cut the tires by a bit less than half, so they both are in contact at each end
@@barrontrump3943 you don't need to balance each wheel, you can under-load them, and then have each's lever arm balance....but that gets mathy.
I'll give you 5 bucks if you wheelie it
Damn bro😂🔥
My thoughts exactly :)
bruh thats it lol
I thought about what would happen, I was thinking he could mount them on both side of the outer rin, that way they would/could safely wheelie
Edit, they already did that and It wouldn't work :/
The suspension will compress more when the weight is being suspended on the different axles. It's like holding a weight close to your body and then trying to hold the same weight at arm's length.
The only fix that springs to my mind is to in some way have the 2 rear wheels have independent suspension. That way, you can adjust each to compensate for the differing load.
Or just don't have suspension 🤷🏻♂️
Or just don't have suspension 🤷🏻♂️
or mount the rear tire on a slightly downward facing angle, so when the rear comes in contact with ground and the suspension compresses, the travel is compensated
The tires could be mounted side by side, this would remove any mechanical advantage because that is what I was thinking too.
or having suspencion in the middle, betwen the 2 whells
I think you guys achieved making a motorcycle feel like you're riding a horse again.
😂
A horse with an even bigger appetite and severe arthritis
All new things are well forgotten old things
You get more leverage to compress the spring when it's riding on the rear wheel, kinda like when you're closing pliers, then it's easier to do when you're clamping on the end of the handle.
You could get rid of most of it by simply just riding without a spring and welding the whole thing so it doesn't have any suspension travel, or you could stiffen the spring.
Also, as another commenter said, you should have 55-60% of the tire left, so you get a smoother transition.
spot on man. I was thinking you put it on a chopper since they don't have suspension usually anyways. I didn't think of the 55-60% of the tire left, but that would probably help a lot too
100% correct, torque is a matter of force multiplied by distance, the further away the centre of the wheel is from the spring (rear-rear wheel is further than rear-front wheel) it will increase the amount of torque the being applying to the shock mount, therefor compressing the spring more on the rear wheel causing that bump effect.
the only way to completely eliminate this effect is by not cutting the wheels in half (no point in the video), welding/removing the shock (resulting in a bad ride) or have a hydraulic spring, changing the compression force to suit the torque each wheel is producing to the spring (extremely complicated - if its even possible)
if you were to have 55-60% of the wheel, it will make the torque transition smoother (correct again) but it will still have the same peak applied torque when there is just 1 wheel on the ground, which will only be noticeable at low speeds. at higher speeds, the slight extra length in circumference will become negligible
@@DeepCarrot The 55% was just to get a smoother transition in general and not for the spring compression thing
That's exactly what I am thinking too.
I feel like bro wasn't riding a bike bro was riding a horse
I thought to comment the same
That is truly remarkable. You have managed to bring back the galloping effect of riding a horse while achieving the speed of a modern motorcycle. I am impressed. 🙃 LOL.
If you can market this you will reach two markets at the same time....The Equestrian community and the Motor Sports community.
The real challenge is to make it look and feel like a horse on one half and a modern motorcycle on the other half. I'll leave it to you to decide which half to change.
Respect. Keep doing what you do. It is a lot of fun to follow along.
God Bless
Don't let the EPA see this
Speed of modern . motorcycle I doubt that
Lol so far horses are faster than this one but soon maybe
I hope he sees this bro. Im rooting for your date.
Use 60% (as others said) and the hardest solid tires you can find (like indoor forklift tires), your bumpyness will diminish some.
It's bouncing because of the different leverage the different lengths of swingarm have on the spring as the weight changes from tire to tire. The weight of the wheels is also changing back and forth between sprung and unsprung weight at different points on the swingarm/lever. Also..., the front tire becomes additional weight while off the ground but the rear becomes a counter weight while off the ground. In other words the weight felt by the spring is changing.
OR he could make it look like a horse
Exactly. Physics - the angle of the force keeps changing.
Came here to say this. You can even see as the forward tyre makes contact with the ground the bike lifts as it's pushing against the suspension at a steeper angle, and relaxes back down as the weight goes on the rear tyre.
I should have read further before adding my comment, as you have already covered the idea. Running the tires side by side would be the only way to possibly completely eliminate the gallop. Even adding hard tires wouldn't kill it completely in it's current state as the different lengths of the armature where the wheels are attaches would react different to the centrifugal force created by the off balanced wheels. Even side by side this could be problematic since the wheels would be attached to a perpendicular axle that would cause wag instead of a gallop. The only way to make it efficient to any usable speed (for a practical lifetime for a motorcycle) would be to add a third parallel wheel and weight the rims with enough precision to stabilize the centrifugal force between the three.
@@theukdave2433 Yes ... I believe you can fix this by making one of the rear half-wheels a larger or smaller (original) diameter than the other...as to how much and which one...???? Havn't thought enough about it yet...LOL
Hey guys, this one was wild!! Haha
So, I’m commenting as I watch so if you say the answer in the video I haven’t made it that far yet!! But to the dropping dilemma, the swing arm is longer and the shock is in the original spot. When on the back tire your weight is increased due to the leverage of the extended arm. Essentially when on the back tire you are much heavier. Pretty sure that’s a big part of why it’s happening!
Thank you, finally someone who understands physics
I was searching for this before I said it Thank You.
Same thing i was thinking, so simple
yep, agreed. weight is the same but the leverage on the pivot point moves back and forth
I concur with this assessment!
I’m loving this motorcycle/e-bike/emoto side of RUclips… y’all are crazy man
the little extra touches in the edits are really sweetening these vids. the butter knife thing and sean flying round the workshop with pipe arms. love it
agreed, the production value is always improving!
and the gloves being thrown at him and just popping on
I think the reason for the bumpyness is that because of the leverage from the extended controll arm. So if you move the suspension to in between the rear tires it should get a little better, but i think the best solution is just to remove the rear suspension, it would be a harsh ride but
You are talking about a rear articulated carrier and yes that would work perfectly
That is exactly what I wanted to write down here. Make the suspension much stiffer and probably will be less bumpy. But the other fact that the middle of the tire will be stiffer compared to the end point of the half will also have some effect. So this will never be a smooth ride I guess.
I think the problem is not the stiffness. The problem is that the center of both rear wheels have different vertical positions, because the holder isn’t parallel to the street. If the holder of the rear wheels would be absolutely parallel to the street it would not be bumpy.
That was exactly what I was thinking
@@faindone there would probably be a difference with stiffer suspension, but not much. There is some truth in what you're saying👍
Your rearmost wheel has to be in line with the swing arm. Youll have to find exact centre where the swing arm rotates on the frame and have it in line with that and the other wheel
i think the bouncing in the suspension is from the difference in leverage on the back tire from the axel from that of the front half tire
I believe your right the rear axle needs lowered a little
The trailing edge of the front drive tire is collapsing, while the rear tire comes around with no weight on it making it taller than the other tire when it contacts the ground. They need stiffer tires or possibly there has to be a time of overlap where both tires are in contact with the ground, to get rid of the weird weight transfer
2 possible fixes. 1) Hard tail. 2) Need to move the spring. There will be a spot on the swing arm where the weight of the unloaded tire will balance the leverage difference of the loaded tire which is where the spring needs to be attached. You may have to also counter balance the wheels too but they balance each other out. It's too early for me to work that physics out lol
O believe you are onto it but and even easier fix might be to just correct the angle of the rear wheel. They also should have cut the wheels just a little bigger then half because the low point seems to be where the wheels join in the wheels are touching because they're not solid so it might be creating a flat spot. ( ) like that.
@@bennyrest9122 yes but the leverage difference is the biggest problem
I used to engineer suspension for Ford... 1) Hard Tail. - Assuming you don't need suspension, this is the best answer. Great job, I would choose this one. 2) Move the spring. - What happens is you find that spot, then you have to manage an oscillating force on the wheel plane for the rear two tires. This would require more weight and parts to manage. Basically, making a single wheel for efficient.
@@Invincibletro do you reckon it also had to so with the face that when the wheel is full it is a circle but wheb it is cut it is no longer and circle and has a flat spot which could also help woth this. C O imaging the C was slit at the top because essentially its a circle if the middle point is removed on the jointed together side. Or do you think its specifically only suspension. I thought it was only suspension at first but I looked closely at wheb it Bobbed and it was wheb the wheels where like this ( ) as upset to while either of the wheels was on the ground.
@@bennyrest9122 When the wheels are like this ( ) this is the exact moment the length of the lever changes, When they are ( ) the lever is the distance between the closest axel and the pivot. What you might be seeing is the A arm angle does change immediately when this transfer happens, lowering the closest axel, or raising it instantly between the transfer between the two levers.
Yep, you need to change the suspension geometry so that it has a strut on the back wheel at a minimum. Otherwise, the weight will always be balanced towards the middle wheel, which means there will be a weight shift each time the wheel changes. Cool concept, though!
needs to be placed between both rear wheels otherwise the center of mass will still primarily be on the front of the rear wheels, causing the middle wheel to compress and leading to the same leveraging issue, albeit to a slightly lesser extent. You got the closest out of anyone in the comments i've seen so far though so gw.
You actually could make an independent rear suspension version but it would require redistributing the weight and altering the frame and completely changing the suspension geometry etc.
Exactly this, and I'm thinking at higher speeds the centurial forces are going to put different leverage on the swing arm, that problem would also be fixed by strutting the back wheel
@@hell_pike9150 at higher speeds the rubber is expanding and flying off.
No no no the ONLY problem is they forgot to balance the tires after mounting.....duhh
The reason it was bouncing was because they did not correctly extend the swing arm, the new length they added was on an entirely different axis than the bikes stock swing arm. Having a strut like what you're talking about would not do anything but likely make it worse, if the extension was able to pivot freely, sure the strut would do it's job. In the end of they 100% extended the swing arm keeping the axle points on the same axis it would be perfect.
You guys rock, pure humor along with ingenuity.. can't beat it.
You really should ride into the local dealer. I need you guys to check out my bike I think something's wrong with it it's not riding smooth anymore.
Not a physics major, but I think the added length of the arm going to the backmost tire is increasing the overall torque applied to the suspension. So as it switches it compresses more
Exactly ,
Agreed. They need to replace all of the suspension, including the front, with solid steel/aluminum. Its going to ride like crap but even if the front suspension compresses, it will cantilever the furthest back tire higher and drop down onto it so there will still be that vibration while riding. Smoothest ride will be with no suspension compressing at all.
Yes the easyest solve is to remove back suspension, or increase front
The bicycle works because there’s no suspension
Should have used the OCC bike. No suspension, no problem.
My take on the bumpiness:
There is a force difference when each half of the tire makes contact with the ground because of the lever effect. The rear-most tire half will have less downward pressure on it than the forward tire half which sits naturally almost right under the rider. The increase in wheel base might also contributes to some flex in the frame, specifically the welded on piece. Wouldn’t be surprised if it would eventually crack from exhaustion.
Combined with another guy who mentioned the ends of tires being more flexible than the middle of them, this can easily create a bumpy ride.
I love that it looked just like riding a galloping horse.
Simple vibration from half wheels and unbalanced weight. That's literally how vibration motors work.
Out of balance bro. You make a good point though, each tire should be longer on one side to hit the pavement before the other leaves.
Yeah if anything was deserving of the "do not try at home" title this is definitely a winner! (It's much more fun to do it at work anyways ;) ) Didn't expect it to be able to start galloping like a horse LOL
hampter
Dude I could not legally agree more. This thing screams at the top of its lungs, BAD DECISION!!! Kids and everyone else for that matter, don't try this at home. These morons are actual pros at being morons. Let them hurt themselves. Then learn from their mistakes
Just 1 q. Why?
Biker and bread do have drilling lubricant
It doesn't overheat
@@slickatoe well, you'd think that's the stupidest thing in the world but today i'll have you know i scraped the ice off my gixxer thaw 2001. it was all good till i hit second and it suzuki'd all over the street.
I think you achieved making a motorcycle feel like you're riding a very fantastic bike
I absolutely love these guys. Not only are they entertaining as hell, but they truly are good people and always send positive energy through their videos. I’m a Hugeee fan, and I just have to meet these guys someday. 💯👍🏼👍🏼🔥
Heck they are Christian lol
I live around 20 minutes from their shop but their hours conflict with my work day so I’ve never been able to visit
@@bigballmagrawl0929 who knows, they still might be nice.
Yes I love that they are Christian. These guys are the best. And yes I’ve worked at a motorcycle dealership for years, ppl don’t realize how much skill and work actually goes into some of these projects!
@@MikeyritZ satans temple mechanics are also really talented.
Im not sure how to solve it, but the issue with the bouncing/raising up and down is because when the REAR rear tire is on the ground there is more leverage being used to compress the suspension, but when the FRONT rear tire is down theres less leverage, causing the suspension to compress less than the other wheel does. So if theres a way to mod the suspension to be farther back it should lessen the issue. Love this video 🖤
OR he could make it look like a horse
@@sycecraft i support this message 😂
This is the issue. the fact that one tire is further back causes the bucking issue. How you could mad this so the spring is in between the 2 forces I have no idea. (note the spring needs to be between the forces not between the tires.)
This....
One solution would be to replace the suspension with a fixed (strong) rod. The swingarm would no longer move, but the handling might suffer a but from that....
I think besides the tires not being solid on the ends and not being 200 degrees, and not being timed perfectly, that they also need to be counterweighted (balanced) It's easy to think them being horribly out of balance is OK because they cancel each other, until you realize they arte at different moments on the swingarm so they are pumping the swingarm up and down.
The frame also needs to be a rigid like the bicycle because the two wheels present different leverage points on the suspension.
I say if at first you get mixed success, try, try again!
That should do a lot. Right now when the rearmost wheel has contact and the other doesn't, the lever arm is long. When the front rear wheel has contact, the lever arm is short. Shock can't compensate that kind of force difference. Get rid of the fulcrum I'd say.
They need to leave the bike as is.
18:33 Damn that was the trippiest thing I’ve ever witnessed that wasn’t a digital illusion 😂 I think if you offset the back wheel to be a little higher maybe even lower it should ride smoother.
Sean, you need to do it to the front wheel as well. That will smooth it out for sure.
😂
im a motorcycle engineer, can confirm
I agree, but then mount two more half-wheels on either side outboard of the fork
I have a masters degree in mechanical engineering and I approve of this suggestion/comment!! This is -Thēē- solution! 🎉 bravo 🎈🍾 👏🏼 😊
Like it says in ...........2nd Opinions 3:5....... "Let's Don't and say we did"
I think strengthening the swing arm will help as any flex with the back-rear wheel contacting ground will cause the front-rear wheel to essentially be below the ground level when it returns to contacting.
Also counterweighting the wheel halves should help a lot too
I was thinking that if they relocated that rear shock over the center of both wheels that it'd be easier and better for the suspension to take it in and maybe less of a rough ride.
Guys you shouldn’t have cut the tires completely in half only a 3rd of each wheel should have been cut out, other than that please try this again 👍
The split wheel is an insane idea..! You did a fantastic job. Crazy to watch 😅
That's a pretty genius horse simulator you've made there. Gotta dress it up to look like a mini horse. Hilarious.
and to think you only needed a quarter outside kmart until now! lol
This man's actually going for a world record first!
Without Guinness!
we dont need them to do great things!
I think some Guinness is required in building something this 😧
They sent this guy's photo to Ripley's they said they don't believe it 🤭
More like Darwin Award
It's a ripoff
The nervous laughs as he was testing it out 😂😂😂
😂😂😂😂
Can´t await the Chineese copy...
Shiting bricks!
I want more! If it could be completed I would definitely get one to show off at Myrtle beach iykyk 😆👍🏽👍🏽
Wow, it actually worked... Awesome!! Strengthen the extension arm, I'm sure it flexes when weight is on the back tire. Like another comment said, make it a 60% wheel instead of 50% so the transition is smoother. Fill the tires with the densest foam you can find before you rivet them. And counter balance the tire as best you can.
Think about leverage and lever length. As others have suggested, you'll need to change the suspension geometry, otherwise every time the weight transfers to the wheel with greater lever length, greater force is applied to the suspension and the swingarm will compress due to the shift in leverage.
I'm not into bikes but y'all are so entertaining and so enthusiastic about what you do. Can't help but watch! God bless!
yep same
My wife and I just lost our 3 week old baby in the NICU - I've been reading James Chapter 1 and 5, you just blew my mind with this scripture reference at a really needed time. I just randomly stumbled on your channel, or it could be said that perhaps God led me here to remind me that he hears me praying, ether way - thank you for that encouragement
Lots of respect for having such a successful bike channel! There are not many out there and you guys do a great job!
Called it from the beginning. The problem with this idea is when the weight is on the back tire the suspension has more leverage on it so it compresses. When the weight transfers back to the front tire the suspension rebounds and creates the bouncing motion. The shock/load needs to be mounted between the two wheels somehow so the leverage affect is equal. Or make it a hard tail. Also making the wheels a little bit bigger than 50% say 60% will make the transition from one to the other easier.
Just my thoughts are the tire would need to be slightly more than half way in circumference to create a smoother transition from tire to tire. Right now there is a slight gap from the amount removed from the cutting in half portion , you need consider the amount removed from each (even as little as I might be. There still a gap, as well as there is no angle of entrance to help create a smooth transition from tire to tire.
I think you would need to cut 2 tires part the 180deg point for a better blend. Like maybe 190-200 degs. 🤔
And maybe some counter weights???
thats not what is causing it to bounce, thats the shifting lever point on the rear arm but I agree that they shouldnt be cutting the wheels exactly in half, kinda surprised they did it that way. There should at least be a little overlap to ease the transition more
Okay, so this will work, but you have to make the wheel halves side by side so it's more stable, and won't bounce. Mounting them properly side by side will allow for seemlessness when you're riding, because they'll be mounted practically in the same spot, and not in single-file line style.
This build is sick but id like to give some input on the bouncing issue
the reason it bumps is because as you transition to the farther tire the weight of the bike has more leverage on the swing arm compressing the shock more. Then when it goes back to the closer tire it has less leverage so the bike sits higher. I would like to see the shock be replaced with a metal rod at the height where both tires touch the ground as a possible solution to this. Also another reason could be that the edges of the tires are softer than the middle since there is less support due to it being open allowing the bike to sit lower from the tire squishing. maybe as someone else mentioned making the wheels with 60% diameter instead of 50% could fix this.
Overall awesome build and I would love to see it revisisited because I'm confident it could be fixed to ride smoother fairly easily.
The leverage effect is exactly right. If these half tires were side by side on the same axle it would be less of a problem. Each half tire needs needs to be indepently counter weighted.
Yup, more leverage! In the bycicle video there is no suspension so it works. Having slightly more than half the tire might help the transition between them too.
DUH!
Well one things for sure…nobody else is making videos like this! I love it! Well done! You guys are RUclips GOLD!
someone did it already
I think it would be worthwhile adding some sort of counterweight to each wheel. Something close to the center. Won't be that much of an issue at low speeds, but if you go for higher speeds it'll be necessary for the wheels to be balanced
He just cut the counter weight, which was supposed to balance it
Came here to say this. Because physics.
@@midnightmassiveproductions7451 Didi this same conversation happen in another video about the same sh!t?
All you needed was a pivot point in between the rear wheels. Attach your rear wheels to both ends of swing arm you made and put that pivot in between the wheels and attach the bike's original swing arm, which would need extending a little, to the pivot point pin/axle, if you will. You would need a brass bushing/bearing in the pivot mount for the shaft. This is just like a tandem axle trailer is set up, as far as the pivot point. You would need a single chain, long enough to go around the two sprockets and add a small sprocket as a spring loaded chain tensioner, in between the two driving sprockets, to take care of the distance change from the engine sprocket, when the suspension moves up and down and the wheels move up and down in the pivot. Just a thought.
The rearmost of the rear wheels has more leverage against the spring (through the swing arm) than the other. This causes the bike to sit lower (as the spring is more compressed) when the weight is on that one compared to the other.
This would definitely turn heads to see this go down the road! Something that might help a little is to take the slack out of the chain between the rear wheel as there is a push then release as each wheel comes in contact with the road and releases, transferring drive torque from one to the other.
a idler sprocket should easily take the slop out of the chain.
The difference of contact points makes the lever arm to compress the suspension compress more/less depending on which tire is in contact with the ground. The weight each of the "½ tires" are similar, and one have a much longer lever arm to compress the spring.
The easiest solution is to remove the spring, replacing it with a solid rod, as I don't think you'll try any high speed shenanigans. There are other ways too, but waaaay more complicated :)
If you want it to be smooth, you need to extend the rear swingarm out to the center point between the two split wheels and put the split wheel assembly on a pivot at that center point. However, why stop at 2? Make it 6 split wheels, each 45deg and phased so that 60deg of wheel is on the ground at any moment.
I have been waiting for someone to put a second back wheel on a bike. Shocked it took this long! Cutting the two back wheels in half I never saw coming! Love it!
I’m already contemplating a t-Rex hill climber out of my KLR.
@@dumntuftv8853 Video, or it doesn't count.
@@jayrowe6473 I’ve got like 5 other projects, I’ll get there!
1:57 DUDE! BOP IT!
The glove edit was awesome.. You guys always look like y'all have the best time.
No, I think with modern tech you could make it possible to tail whip a motorcycle. It probably wouldn't be cost effective in anyway but it could be done.
Also, if you bent the ends in on each side a bit more you could achieve a flush surface w/o a the bumping up and down. It's the initial contact that is causing this issue, so if you make the intro and outro curves more severe you can bypass that a bit.
The pivot point of the arm puts a load on the closer to pivot point wheel. Try lifting the rear about an inch so when you sit on the bike the weight distributes a bit more even on the tires but bumps will still be causing this hop problem
Maybe like a dual axle trailer. An equalizer arm in between the wheels would balance out even through bumps
I’m sure that’ll be another cool idea for another video
Looking forward to more 💪🏼
The load on the suspension changes as weight moves from the closest wheel half to the rear wheel half due to the leverage on the arms. If the 2 wheel halves were side by side (like a dual wheel truck wheel) it would probably work.
👆
@@user52613 Good point, you are probably right.
That's was my thought exactly. I think the connection between wheels also allows some slop.
Side by side would be a terrible idea. Imagine taking a corner.
@@Mr_Glenn yeah, scratch that for sure. It’s an accident waiting to happen.
Who else is here early to see if it works
Literally everybody watching the video?
I'm 4 minutes in I think it won't.
Compliments to your parents on the choice engineering of your name
Me
caught me
Try putting the pivot midway between the two tires with chain driving both from sprocket at pivot point. Would be fun to see result.
here is an idea about how to solve bumping issue. There are two issues that I noticed. Leverage diffrence between both parts of the wheel and no overlapping.
First you need to extend the swing arm furher but do not change distance between both parts of the back wheel, move the front part of the back wheel further back instead that way leverage diffrence between two parts of the wheel relative to front one will be significantly less.
Then instead of cutting the wheels in half and having 1 whole wheel in total you'll need to cut out only 45% of the wheel so you can have two 55% wheel and one 110% of a wheel in total. That way having something extra on each half of the wheel you'll elimininate the possibility of that back wheel losing ground contact ever. even a split second loss of ground contact will result in significant bumping issue.
Bounce Baby Bounce! Haha 😂 Great job guys! Love the videos! So your bounce is because of leverage being applied to the suspension. The fulcrum point is moving back and forth with the change in drive wheel halves. If you want to keep it a softail you could put an additional spring and shock angled back from the rear of the bike, closer to the rear tire. It would need a stiffer spring rate than the existing spring to balance the compression, so some load calculations will be required. Cheers!
The hopping is coming from transition to the outer tire which adds more leverage against the suspension making it drop.
Making for funny bouncy motorcycle.
You guys are awesome!
No it's hopping because they used 2 different sizes tires
@@Wreckz_Tea It will hop from the leverage changing even if they used the same exact tires, and no matter what pressure/stiffness/etc. they managed on the tires either.
I guess that bounciness is when you cross motorcycle with a horse
Ok. This is the coolest thing ever. But I think you missed an opportunity. Two clown horns at different notes inside the tires would have put this right over the edge.
THESEEEE GUYS ARE AMAZING !!!!!!..... AND SHARE A WONDERFUL MESSAGE OF HOW TEAM WORK SHOULD BE AND SPECIALLY THE FUN THEY DO.... respect++
I just want to point out that at 17:11 the back wheels completely clear the grate in the street.
The reason it bounces is because when the back tire is on the ground, it has more torque on the swing arm which compresses the suspension more than the front tire, making it bounce when it transitions from one to another
exactly!
The easiest way to fix it would be to lower the rear(-est) wheel and adjust it's shape to something resembling half an egg (to allow for the time it takes the suspension to travel). Hmm... ...maybe it's easier to make a separate suspension for that 3rd wheel, but then you need to allow that arm to move and ultimately need to extend something from the body of the bike over the 3rd wheel.
There is no easy way to fix this IMO.
@@alexandercamillo3771 more leverage = more torque per given weight.
Needs to be a hard tail
@@NWoutdoorsman yeah
Hey guys, just wanted to say that the reason for the bouncing up and down is due to the change in leverage. Since one of the wheels is further back it has more mechanical advantage over the suspension due to the increased distance of the swingarm , make the back suspension in center of both tire's
18:19 "It's like driving a caterpillar"
(EASY FIX!) The reason your motorcycle is going up and down is because the rod (frame where your tire is connected 7:59) is not perpendicular to the ground. Your frame is inclined at a very small angle. This means the distance from the center of the rod to the ground will be more than that of the edge of the frame. Even if the size of the tire is the same, it will go up and down. On the other hand, it will work fine when two tires (not split tires) are connected because the forces are distributed. And in this condition, the tire at the edge is holding more load. There can be two ways to fix this: either the rod must be perpendicular to the ground (to do this you need two bigger tires of the same size) or when the rod is inclined, the tire at the center must be a little bigger than the last one. And I think the first option will be better.
not to mension the suspension. if there is eny it will still bounce.
yes ah
two different sized wheels would also mean that you are driving two different speeds at the same time, as they have to rotate with the same rpm.
@@LoneStarr1979 no. the bigger wheel have to spin faster to make a rotation as the small wheel.
all he needs is to remove the suspension.
Instead of strapping the suspension down in the back, you need to install a solid strut to keep all three tires running on a flat plane. With the change in wheel base length, you are changing the leverage that your weight has on the shock, so it changes height with each half rotation of the tires. If you remove the shock motion, you will also remove the up down motion. Just weld in a solid vertical riser on both sides where you had the ratchet straps before. If your riser is too short or too long, you will still have a bumpy ride. If you get it the right length, the ride should smooth out.
This was an awesome start to my day. Lots of laughs and such a joy to watch you make the most amazing bike ever! 🤣
Craig does it again! ( Sean, I assume was busy doing all the behind the scenes technical stuff) I’m a bike mechanic too and I can’t get any work done because all I do is watch and rewatch you guys! God bless you guys and stay up on two…. Or three…sorta
This is honestly the best motorcycle channel ever. Thank you guys!
swing arm probably needs to be bent slightly upwards after the 1st half tire to even it out. maybe even use like 52% tires instead of half tires withe the rubber capped off or rounded at the end to catch better like a fillet.
i love how you can tell they enjoyed every bit of this
BTW: It's going up and down because the lever that puts force onto the suspension is changing length every half turn.
The solution would probably be to put the hole thing at a slight downwards angle (higher at the front, lower at the back) until it's "perfect". Or just replace the rear suspension with a fixed rod...
the solution is put the original wheel back on
garie amartiņi jāiebūvē starp diviem pusriteņiem.tad būs okei.
The design looks like it would be applicable on off road and snow sections if it can switch itself from the street mode. Can't wait to see what future technology we can come up with.
Jā tas būtu besceļiem domāts,jo pie liela ātruma neisbalansēti pusriteņi izdalītos.
Literally reinventing the wheel. I love it.
Love watching videos, I don't know if I could work with people who are this overall positive about life though it might rub off. Keep up the good work.
The rear tyre has longer leverage on the swing arm so it's compressing the suspension more for the same weight. So maybe replacing the rear coil spring with just a metal tube would fix that. You won't have rear suspension anymore but that's "not an issue" on choppers so it'll propably be fine?
or mounting a counter balance on the tires. would be easy to do, just make sure it does not fly off
exactly, and since the furthest rear axle is above the pivot point of the arm, the wheel closest to the body of the bike is actually lower down and closer to the ground so its just pushing itself back to fully leveled, thus creating the shake
Yup
My Scottish engineering solution to the bounce problem is to fit a pivot point on the new swing arm, each side, in-between the 2 rear wheels to give the rear wheel a little independent movement vertical. You could possibly force the rear wheel to stay on the ground using a set of small dampeners or springs on each side, to keep it pressed against the road surface too! 🤔👍
My indigenous engineering also came up with the same deductive conclusion & possibly using tires & rims just alittle longer than half a rim & tire.😳🤔👍🤣
That Scottish idea won't work, as the 2nd swingarm will drop down towards the wheel that isn't touching the ground. Easiest solution is to fix the rear shock, so that the swingarm extension piece is always parallel to the ground. Also the front suspension should be fixed, because it has the same change of leverage problem.
Muita informação para mim, falando que meu cérebro não processe tudo isso de uma leitura só kkkk
@@fritsified5952 The pivot would have a block to prevent the extended swingarm from dropping past the range of the primary swingarm, allowing for compression but not over-extension of the extended swingarm. The front swingarm would have to be limited on over-extension too
@@TheReal10bears If you prevent both sides of the seesaw swingarm to drop it's the same thing as being fixed right? Anyway, you'll still have the issue being the distance between the contact point with the ground and the original swingarm pivot that keeps changing.
This man’s tires are still loading
I think its the "leverage effect" that makes it bounce.. cause the leverage length changes when it touches the ground on the different tires. Really great video anyway :D
That does not happen on the bicycle. What causes it on the motorcycle is the rear suspension varying the angle of the swingarm based on the rider weight.
You are correct sir
@@twotone3471 which is caused by the leverage effect...
Have you considered adding weight on the other side of each tire to balance it? Right now you have two off-set wheels throwing torque all around and definitely adding to your shake issue.
nah i don't think it works like that. my guess would be because of the suspensions, was reading some comments and saw someone says there were 2 different leverages, i think it's because of the further wheel not being close made the bike and rider heavier rather than the wheel closer thus makes the bike bounce when moving ( does that makes sense? ), it didn't make some bounce action on the bicycle video because it had none.
19:20 Note for why it's bouncing: Due to one wheel being further back and there only being two wheels it has a sorta situation like a lever, especially noteworthy due to the curvature of the earth making it more notable because the closer tire will be higher up, pushing up against the ground.
I don't think the curvature of the Earth really matters here
The earths flat bro, "Curvature" What an amateur
"especially noteworthy due to the curvature of the earth making it more notable because the closer tire will be higher up, pushing up against the ground."
lol
Imagine your chain snapping or coming off on a split wheel motorcycle.
You guys must be fun 😊 to work with. I like how you come up with your ideas on this bike, it's so freaking outside the box 🎁. I hope you don't change, this world needs more people like you guys. Your like the Nickolai Tesla of the
Don't you dare compare these to the genius that IS Nikola Tesla !
You should be ashamed of yourself.
They got to him 😞
@somerandomname9252no he said in the beginning, everything you can do to bikes works on motorcycles too
Lots of fun watching you guys! Got my laughs in. Like other's commented, I think 60% tires would be better and maybe some way to make them solid rubber tires.
1. The swing arm extension is acting like a cantilever causing bending due to the support from the suspension being placed so far from the 2nd sprocket.
2. When the load from the bike shifts from the first tyre to the second tyre, it causes a massive jump in the radius of the moment torque in the swing arm, causing the force at the suspension to go up and down, which in turn increases the bouncing caused by the bending in the swing arm.
The only way to deal with this is to introduce another suspension system onto the second sprocket, which should be an equivalent mass system of the entire first suspension system, so they work exactly the same.
18:36 bro's tire look like they loading
😂
You should be able to fix the bouncing by welding a support trust the the frame under the seat. The back wheel is twice the distance from the shock so it has twice the leverage and need half the force to compress your suspension
I feel like you would have a lot more credibility if you knew how to spell truss.
Weld the back suspension up is probably the simplest idea, the support truss would only strengthen the back end from falling apart during vibration it wont stop the bumping due to leverage on the suspension. They need to either weld the back suspension up, or change it to an old style dual shock where is connects to the vey back axle, going to be a bumpy ride either way.
Yeah, the bicycle was a hard tail, that's why.
You got it.
That's what I was thinking when the suspension compresses it lightens the load on the farthest wheel! Putting that long arm up in the air sort of? All-in-all at least it was! LOL
Kind of surprising?
i was thinking the same thing. i could not understand how they could not figure it out. it took me just couple of seconds.
Add a counterweight to each wheel opposite the tire side.
Edit: if your rear suspension is designed to perform at different angles relative to the frame this will never work. The middle wheel will be closer to the ground under heavy load and the rear wheel closer under light loads. This is because the center of the suspension should be between the wheels, not completely outside of their balance.
A simple fix would be to angle the new bar attaching the second tire slightly towards the ground. Thus the increase force created by the longer swing arm when the second tire hits is counter acted with reduced height from the pavement. Would need to be angled differently for each people of differing weights.
Great video. Hope my explanation made sense. Though I'm sure someone has already mentioned it and better, in the 6k plus comments!
DC
A simple fix would be to burn this atrocity.
On general, guys, The best way for how to prevent speed wobbles on motorcycle before you ever leave home is to do regular bike maintenance. Frequently check components of your bike such as its suspension, aerodynamics, steering damping, and wheels, especially if you purchase used motorcycles.
I would make that a triangle with the bars going up towards the seat but with suspension to the seat. Also pretty sure you don't have enough tire. The transition could use a bit of overlap.
The physics behind as to why you're bike is bumping up and down is bc your center of mass on the middle tire (the first back tire) is catching your weight every time you move from the rear tire to the middle tire, and since the bar is holding the rear tire from going down, it's actually on a wide obtuse angle (think of it as a really long, wide V). One way to fix this is to remove the suspension, but that is a pretty hefty takeaway from safety as you'll have to be really careful on the road. Another way, which I think is safer, is to make the bar holding the rear tire adjust 2-5 degrees depending on how much the bike moves down when transitioning from the rear to the middle tire. This way it'll make a smoother transition from the middle to the rear and vice versa bc there isn't anything holding the rear tire up and the middle tire is in contact with the ground. The only problem with this would be the rear rubber of the tire might not be the first to contact the ground, but rather the rim, but I think that can be fixed if you roll the ends of the rubber over the ends of the rim, kind of like when your bottom lip covers the upper lip. Hopefully this helps.
Yeah, the rear tire has much more leverage against the suspension, causing it to collapse, while the "middle" tire then lifts it back up, because it has less leverage on the suspension. Would have to make the suspension all Solid (no suspension) for it to go away... but even then it might have considerable leverage against the frame to break it. (and on top of that, the force of the unbalanced tires).
This. The suspension is magnifying the transition between tire two and three. Just for giggle's replace the rear spring with an iron rod.