Tuning with Shock Angle - Part 2: DETAILED Version
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- Опубликовано: 9 июл 2024
- This video will explain, in expert and excruciating detail, exactly how to tune your RC Crawler (or most any suspension vehicle) using the shock mounting angle.
00:00 Intro
01:07 So Many Mounting Locations
01:13 Fundamentals
01:55 Ride Height v. Shock Tune
06:52 Performance Tuning Preview
08:03 Spring Force
13:06 Damping Speed
16:30 Wheel Travel
19:53 Progression (ADVANCED)
20:27 Center of Gravity
20:50 What Did We Learn?
21:37 Outro
Thank you for the schooling! Smarter every day!
Any time!
That Gwin jersey on the background though 🤘
I also have the famous chain-less run frame.
Super helpful. Now I’ve got to start testing and reworking all my rigs. Thanks!! Subscribed!
Thanks for the sub! The tuning never ends. Hopefully that is one of the fun parts. Just don't let it own you.
This is the best guide I've seen on this subject on RUclips!
Subbed! :D
Thank you so much! That is very nice to say. I tried hard.
Super awesome info! Subscribed! Aloha from Maui 😎🤙🏽
Thanks for the sub!
I've been looking for an explanation on this, thankyou!
You bet!
I’m late!!! Thanks for this and a big THANKS for the visuals and percentages, you probably do not have any idea how many ppl you helped with this video! Happy rcing my friend
Very kind of you to say. Thank you.
I noticed all the specialised pictures and rc shocks so I had to click. What's the connection with you and mtb?
@@Anthonyholdway I was the lead mountain bike frame engineer at Specialized for 24 years. There are a couple bike videos on my page since some people follow both.
Nice and thorough, answered some details that weren't super clear to me before. waiting for the part about progressivess
Coming soon!
Good series of info vids, I’m enjoying them.. 19:30 small error in travel limiter. A 3mm spacer not 5mm spacer as the shock to wheel travel is not 1:1 at the angle. (Also not infinite for flat, it would actually limit travel as the shock cannot extend beyond its length for travel up or down, it would be a tether at that point, assuming a vertical wheel travel)
Thanks for the kind words! Nice catch - good opportunity to publish some additional context.
You are technically correct about the shock at horizontal and infinity. It would act as a leash or tether, but this wasn’t meant to be taken literally. It’s merely a visualization mechanism to help remember which direction that angle changes affect the travel.
Perfect explanations 👍🏻 Very usefull, thanks.
You are welcome! Thanks for the support. I have more coming.
Excellent Video 🤘🏆
Thank you 🙌
Awesome vid! Graphics much appreciated. I'm an abstract/creative/artistic brain, so nice to have info from math/technical brained people. Being a MTB junkie from the 80's, early 90's, myself and a friend, that was very technically minded (aircraft engineer trained) but also with an eye for good design aesthetics use to spend hours in our fav coffee shop, talking about bike design, etc. But this bled over into furniture, tools and other things. We coined it as 'coffee shop engineering'. Where technical knowledge meets and is challenged by non-technical, out of the box thinking/problem solving based mostly on just creative imagination. Very fun and good for hours of chat (and preventing others from sitting at your table....LOL!)
Something that is beyond my learning and may be up your alley for a video would be the relationship of sprung weight and shock performance or effectiveness. I notice there's lots of attention paid to getting weight down low and unsprung. But I also notice there's a lot of rigs that, as they are sitting level and static, are just sitting on the springs with no compression. In my 'coffeeshop' thinking, this isn't ideal, as there's potential in the compression direction but none in the extension direction.
Just a thought. Feel free to bust this line of thinking.
(with this thinking also comes to my wish that springs for 1/24th SCX size crawlers came with even softer springs. Or at least be able to find the tempering temps so is would be possible to redo them softer)
Again, thank you for your generous time making these vid's for those of us hiding in the back of the class, doodling. Or sitting in coffee shops, stretching out cold cups of coffee b/c we spent what little spare money we had on more important things like purple anodized derailleur pulley bolts! And if you haven't, check out 'K-Tech RC' wonderful ano'd RC parts.
Cheers!
Bert the Weldor
Thanks for the kind words. For an RC crawler, the suspension objective it totally different than any other vehicle. Absorbing bumps isn't even in the conversation, so sprung weight is not a factor. You are correct though, that full droop is not the right setup for a vehicle at speed that needs to take in bumps. Crawler suspension is really just for articulation, and I don't even run springs at all personally. Many people will have coil springs and then put pen spring or hair bands to compress those spring. Then they just cancel each other out, so why bother to even put on a spring in the first place. This advanced thinking has not hit the RC Crawler crowd yet, but I am working on it. Enjoy!
@@BoomslangSuss Thank you so much! Great info and pretty much lines up with my uneducated, coffee shop rationalizing. Agree regarding the hair bands. Esp. when put on at each wheel. I can see one in the center, to effect the articulation to just one side or the other. But still didn't make total sense given, as you said, the springs really being more for absorption of bumps at speed, not crawling in these little things. And the only issue with sprung weight, chassis and above, I could see would be it's height. The higher that weight is, the more apt it would be to cause side hill issues. This also being effected by axle width and the point at which the sus. links let go and "flop" up on/from the uphill side. I'm considering going spring-free, save for either a cut down spring (2-3 coil loops) or even a tiny neoprene bump stop. Mostly just for wear and tear and softening any full chassis drops so they don't bang hard, transmitting that shock force to the ground. But even that I'm sure is very very small on little 1/24th.
Again, thank you for the valuable insight!
🙂👍
@@wingnutbert9685 I am working on center mounted extensions straps myself - make no sense to have one on each side as you have deduced. There is an after-market bracket for SXC24 from LGRP but their the only one's I have seen thinking in this direction.
Also, I put a soft o-ring on the shock shaft for bottom out control - I don't like a hard CLANK at bottom out either. You can see it in my spring removal video. Smart guy you are.
ruclips.net/user/shortsLFdbIvrj3OM?si=AuxO_jG55UDse6X0
littleguyracingparts.com/products/lgrp-brass-limit-strap
Once i heard trigonometry i almost backed out because i knew i wasnt going to understand anything 🤣 but this was actually very easy to understand and im an avid RC'er and motorcyclist.
Nice! I appreciate the feedback. I hope I’m making it very simple and clear. The intuitive version of the same subject matter will be coming out very soon. Same content, different presentation.
You should do an episode on Citroën suspensions...
What era?
@@BoomslangSuss 1930-60. I don't know if it would work in smaller RC vehicles though.
Any plans on a vid discussing shock angle, but pertaining to perpendicular to the frame? (if it's something that has enough performance factor to warrant a vid).
Again, Thanks! Have a great weekend!
Yes. This applies more to buggies and trucks as they often have shock towers with holes to tip shock inwards. I will do a video on it for sure.
@@BoomslangSuss Great! Thanks! I haven't seen it a lot on crawlers (I'm into SCX24 scale size) and figured you're the man to ask! Look forward to it!
The spring rates from the losi springs that you mentioned indeed seems to be very far apart, but the element/axial/vanquish springs tha ti know are more like 50% difference and not 90%
Nice. We need that.
Wow! Great video!! I just in time for me, I race off road RC and have been investigating the effects of shock angles, mounting positions, and spring choices right now and this is great stuff. I got a setup I would like to run by you on my 2 wd buggy and see if you think I am correct with my thinking but I don’t have time to type it all out right now, is that cool? I am at work on a short break right now
Post it right here when you can I will take a look. I do plan on another video aimed at racing buggies and other cars in the future.
Ok, I was messing around with my 2 wd buggy at an open practice one day and the rear of the buggy was loose so I was trying to get it more hooked up. I usually just change springs, go lower and higher and whatever seems best I go with, but I thought I would try something different for a change and I decided to try changing the angle of the shock and see what I could do with that. Well I knew that the inward mounting hole on the arm would make it softer and the out hole would make it stiffer (I am actually wondering about that a little now though after watching your video, but we won’t go there right now) so I went for the shock tower mounting points and only made changes there. My buggy has 3 holes on the tower and I was in the middle one. Well, according to some setup helpers I have and some things I have read on the internet, you lean the shocks in towards the center of the car for more side bite, so I did, I put the shock in the innermost hole on the tower. I checked and re-set the ride height and went to the track to try it out. Well to my surprise, it was worse and even more looser. So then I decided that I must have went in the wrong direction and I changed the shock to the outside hole on the tower, re-set the ride height and it was way better than the middle and inside hole, not really what I really want out of the car but better, so I left it there
Oh, I accidentally hit the send button, my bad, I wasn’t done yet, where was I…. Oh yea, so I am actually thinking after watching your video that when I had the shocks in the inner hole, it made my shocks stiffer against the roll of the car because the shock was closer to a 90 degree angle with the shock tower and how the tower rolls and pushes on the shock in a corner. So I should have stayed in the inner hole and put a lighter spring on at that point I am thinking, correct???
I believe I am following. Don't worry about the angle of the shock tower to the shock - that is not a factor, but I can see why your mind might go there. If you move inward on the shock tower, you are softening the spring. If you move outwards it's getting stiffer. Also, travel, damping rate and progression all change, but not too dramatically - the spring stiffness is the biggest factor with these small changes on a buggy. Crawlers people are laying their shocks down by 20 and 30 degrees at at time, lol. You are right about the A-arm - inward is softer, outward is stiffer.
Also, if body roll is your concern, there are difference settings altogether for that - roll-center and sway bars.
WIthout knowing more about the full picture - track roughness, tires, etc. I don't think I can tell you which direction on the shock tower is going to improve performance in this specific instance. I can just tell you what happens when you move holes - then you decide if that's working - stiffer or softer.
I will publish a video soon that is more specific to buggies and trucks.
Oh awesome, thank you very much for all your help, I really like your video a lot, I really understand everything you are talking about in it, it’s very helpful, I can’t wait for the next video, it sounds like it’s going to be a good one
I disagree that extending only the shock length and not the angle doesnt affect the spring/damping effect. If you had a shock to swing arm angle of 90° and just extend the shock length to raise ride height then you will not still have the same 90° shock to swingarm angle therefore a change in spring/dampening affect.
You are absolutely correct. If you are lengthening a shock for more travel you should do it on the chassis side. Otherwise you change other variables as you point out. Thanks for that.
Nice video. How did you derive the Wt change % for Losi oils? For example 10 to 15 is a 50% increase but you state 40% so I assume there’s another condition?
Edit: CST appears to be the answer to my question…
Good question! I used %Difference rather than %Increase or %Decrease.
I don’t think cSt is the answer because going from 350 cSt to 425 cSt (30 W to 35 W) is over 20 % of an increase in those units.
@@Glocktologist We're both right.... The left column needs the 2.5WT's added. The first one I looked at is correct but they go wrong from there. The right column is using numbers assuming an increase of 2.5 in WT but that WT needs converting to CST as WT is not a standard for kinematic viscosity.
@Matt-ex9vk I’m not an expert in fluid dynamics so I don’t know which unit should be used but cSt sounds right to me now as well.
This applies to any units or labels on packages. Many manufacturers simply call their springs soft, medium, and hard. If they were to label them 1, 2, and 3, we could put those numbers in a table but we couldn’t say medium is twice as hard as soft. That’s why we use lbs/inches or a metric equivalent: an increase or decrease of X percent in the numbers means a change of X percent in the actual spring rate as well.
Any springs I buy I put on a kitchen scale and compress by a fixed amount to measure the actual rate. Not lab accurate by any means but helps with comparisons. I don’t like running ”red springs in the front and blue in the back”.
Suspension setup and tire choice, the two most important tuning options in any RC vehicle. Everything else is just fine tuning. And, yes, let's not argue dampening vs damping. The two words have been used interchangeably for years so, lets not split hairs. That being said, I can hardly wait for the pre-load doesn't change spring rate argument! 🙄 Btw, excellent video!
Thank you. I enjoy sharing, and the discussion. Guess I better get working on that spring theory vid! Just wait until the hair band/pen spring video drops - that will blow some minds I expect.
foxacademy.ridefox.com/2021/05/is-it-damping-or-dampening/
Im new to the hobby and i think experiencing with weight drastically change the driving.
@@user-mt5lh9mj9b It is VERY important. ruclips.net/user/shortsE2-5ISJsHjQ
@@BoomslangSuss I have a slash bl 2s but that crawler exemple is great. Its not always what you think ! Without weight, my slash tumble to much and its the front is lifting so I lose control. I did not take a deep dive in it but i see people putting weight in front for the most time. It helped me not to flip but i lost traction. The front axle became the pivot point so it was hard not to do burnouts all the time. When i tried weight in front and rear, i felt it was to much weigh for nothing. Alot of pressure on the outside front side when turning too. I removed the front weight and now i feel i found a sweet spot for my needs. The only problem (not for me) is that im basically stearing with the gas rather than the steer. Im barely turning with the throttle full. I need to slow down and reajust for a sharper turn. Yes it can tumbles but everything going that fast and turning with a really sharp angle is gonna crash. Except when i touch the brakes... I can do a freaking 180° at high speed and its hard for me to understand why haha
Can i change the angle but add longer shocks so my ride height stay high ?
If you add a different length shock, be sure to select a new mounting hole in the right direction. Watch the video closely around 5:35
@@BoomslangSuss thx maybe i dont get it or my question was not clear. If i put the shocks closer to the wheel, can I put longer ones to compensate for the height lost ?
@@user-mt5lh9mj9b I need to understand better what you mean. Are you talking top of the shock at the chassis or bottom of the shock on the suspension arm? Looking from the side or looking from the rear?
@@BoomslangSuss ill try my best. English is not my first language. Lets take the rear as an example. I have five hole on my slash suspension arm. So i can change the bottom position of the shock. I have only 1 position possible for the top. If i choose the hole near the wheel on the arm it puts the shock in an angle and lower the ride height. My question is can i put the bottom shock in the hole near the wheel but then use longer shock so i dont loose ride height. It would be better if i had a picture lol
@@user-mt5lh9mj9b I understand what you are saying now. Yes, you can do what you say, and that is a good idea. You probably do not need much longer shock - you could likely just unscrew the rod end 1-2 turns to make the shock longer. Does that answer?
smarty pants (in the best way possible)
Well, my pants thank you, sir
I think the changes in shock oil viscosity are not quite what your table indicates. Oil ”weight” isn’t the correct unit as far as I know.
It’s the same when you calculate changes in temperature: convert to Kelvins before anything else.
Going from 30 Wt to 35 Wt is roughly a 16-percent change using those numbers but going from 350 cSt to 425 cSt (same oils, different unit) is a change of over 20 %.
I’d consider converting the viscosities to Pascal-seconds and see how that table looks like.
Interesting line of thinking. Weight is a generally accepted method of comparing viscosities. But that doesn’t mean there’s not a more accurate way if you are mixing calculations.
Weight can be used to compare viscosities but the unit you choose affects whether you can say one oil is X percent of the thickness of another oil.
For example, 68 F is a nice and cool room temperature and 102 F is an elevated body temperature. 102 is 50% more than 68 but 102 F is not 50% warmer than 68 F.
The same applies to comparing oil viscosities. All units may not allow you to state the relative differences correctly.
COG can be changed easily by flipping the shock around...but then you have more unsprung weight....for rc that is a uninteresting fact.😎
True, true and true. 😂
I remember doing that when I was a kid lol!
The increase in unsprung weight is surprisingly small.
People make a big fuss about it but the aluminium shock body and silicone shock oil are not as heavy as their size suggests - contrasting with the steel shaft which weighs almost three times as much as aluminium and eight times as much as silicone for a given volume.
Actually weighing the components reveals the difference to be a few grams and it’s not even at the end of the suspension arm. Nobody bats an eyelid when you put aluminium hubs on your buggy but flip a shock and everyone loses their marbles.
The top-level drivers in Europe have been turning their shocks around and winning races so the much-feared unsprung weight has also been proven in practice to be an exaggerated problem.
@@Glocktologist Facts.