Love you and thank you. Finally an intelligent mind within the industry, I hope people appreciate you and your valuable knowledges. I watch all of your videos and inventions. Guys like you make the World a better place to live in it by having true knowledge. Much much appreciated.❤
Fantastic info and so well presented 👍Unfortunately, most don't have a choice and go with the current trend / industry offerings. Also, re: rear stay lengths - it's fascinating how the same stay length can be used across all sizes offered, I'm using Spec Chisel as an example: same 432mm from size small to XL - meaning weight distribution variation @ BB almost 4% depending on the size!
Your doing gods work Dave! ❤ I really liked that you gave us some numbers to look out for. Im asking myself about other factors like stack, bb height etc... i know Aston made a video about his bike going a little into it, but i would love to see one of you two (or maybe even both) give us some tips to find the right geo bike or even to get a custom one build. Thank you alot for sharing your knowledge 🤟👍
Many thanks for this very explanatory video. A master pièce of explanation demonstrating the vast majority of the bike industry looks like a the fashion industry.
Hi Dave, congrats for the video. I have a 470mm chainstay, 500mm reach, 1320mm wheelbase custom made hardtail bike (I'm 180cm tall), and couldn't agree more with you. In my opinion, the only downsides in comparison with a "traditional" bike are: - more side lean is needed to corner on very twisty, old school trails; therefore, switching between consecutive turns needs a lot of aggression; - the added front wheel loading makes intentionally lifting the front wheel over obstacles quite harder. Now I'm going to experiment with mullet set-up and higher rise handlebars. Happy Christmas holidays!
@@RULEZMANSUSPENSION I do agree with the sentiment but a 460 CS on a 1300 WB bike gives the rear 35% of the complete wheelbase and 480 CS a 37%. How long chainstays are you saying you want? a 440 CS on a 1240 WB bike gives just over 35% ratio of WB as well.
@@javisst44 nice calcs bro. 🎖: MOST MODERN adult bikes are 1280-1300 and still retain 430-435-440 CS, while we should move to 460-480 range . 1240? wow what is that a kid’s bike? yes, that cS is well proportioned for such short wb
So is there a front center to rear center ratio you like. My bike at static has a 1.8 ratio and it corners quite well, but I think it could corner even better
Yo man! Awesome video I see why now you ride banshee bikes. The geometry on their bikes are good. I am 6’1 185cm I ordered a titan in XL I see now the “bigger head tube” “longer chainstay than other bikes and high stack. Higher bb it makes sense! I am glad to have bought this bike I cannot wait to build it up and ride it
@@RULEZMANSUSPENSION hahah I wish I could with the RRT suspension I am swapping a lot of my stuff from my meta. And just like you said I am struggling with that bike with the long reach and shorter chainstay! And what’s the zero back plate?
Fantastic video thanks! A big difference between motos and bikes is the rider is an essential handling piece as the system center of gravity can be changed much more than a motorbike. How do you view the effects your ideal setup would have on jumping via 1: build ramp and 2: bunny hopping? 1 a moto can do but 2 is unique to bicycles.
I have been saying this since the early 2000s! I currently run 35mm stems, but I would love a 15mm stem. I don't see anywhere I can get one though. As for chainstay length, a shorter chainstay gives a bike more pop for jumping. Longer chainstays make pulling up the front wheel more challenging and because many riders like the catch air a short chainstay makes that a lot easier. Comparing a motocross bikes chainstay to a bicycle is a bit odd considering you have a motor with a bunch of power to get the front end up, something you don't have for a mountain bike. On a bicycle you have to control the pitch of the bike with your arms, legs, and body position. So I am not so sure I agree on your statements about making chainstay lengths longer simply for more equal front real balance during cornering. You do a lot more on a mountain bike that cornering so the frame geometry needs to be well balanced to accommodate all the different situations. So for my height of 5' 7" anyway, a 435 - 440mm chainstay is perfect. As a rider gets taller, the chainstay length should get longer, not just the front of the bike.
15mm stem: email me. I produce them. CS: races are win on corners not on hopping, and long cs makes you cornering with more speed overall, so it is faster. who think at hop as his first passion shoul buy a 24” bike or dirt jump
@@RULEZMANSUSPENSION Sure, for racing. Most of us just ride for fun and enjoyment. And yes, we still want higher performing full suspension or hardtail bikes. A DJ bike won't be very fun to ride on most singletrack. I don't want every manufacturer to design every regular consumer bike for what the highest level racers need. Most lift access trails and flow trails have jumps and fun features in them, think freeride. I think one of the biggest problems in the bike industry is they have racers determine what everyone else should be riding. Maybe the term freeride needs to come back and Enduro can be the racers bike with long chainstays, super slack head angles, and so on. I absolutely agree with you about the stem though. And yes, I will contact you about that stem. ✌️
My second DH Bike was an YT tues vor 15 years. While i have No Money i buy it in Large but i am only 1.70. than i Put the on Off stem from the Mondraker on it. All Guys laught but that was the Best.
Im currently puzzling with bars that are comfortable for me so I have round 7 different ones at home. I measured them all and one thing I noted is that they very strongly differ in how much they reduce the Reach. E.g the ergotec with 12deg reduced reach by 70mm. The SQlab with 12deg however only 35mm and the FAST flex one sits somewhere in between. All other bars with 6deg (Renthal) or 9deg (Nukeproof) sit in between. Its really mad. I guess that should be added to the equation of correct stem length because with that Ergotec my 40mm Stem is effectively Zero offset - and it feels great :)
you are not uptiltinf handlebars up by 5 degrees to follow natural hands contour, as well you are probably ( I guess) measuring end to end, while in reality the line should be drew from about 7 cm inside each hand of the handlebar. ANYWAY: 7 bars at home, My compliments, you invest a lot bro
Complimenti per le spiegazioni chiarissime. Una domanda: tu Dici che preferisci le taglie XL ma in realtà la maggior parte delle case usa le stesse proporzioni per tutte le taglie. Quindi prendendo una taglia più grande si andrebbe a peggiorare la posizione del Cg. Mi pare che ad oggi qualche casa propone chain stay “ tailored” per ogni taglia. Si potrebbe avere quindi un miglioramento. Dimmi se il mio ragionamento è giusto e cosa ne pensi. Grazie mille!
Hey Rulezman, geat video, thanks. I'd like to comment on two things. - Moto vs bicycle. I read an article by someone from Mondraker a while ago on why they abandoned the 0 mm stems and why it works on moto. The deal (as far I can remember) was that on moto the whole system is way heavier and more stable and therefore does not rely on the stabilizing effect of the cantilever (stem) while going straight. Therefore even negative stem length works on moto that would destabilize the ride. Mondraker figured out that the optimal effective lever for mtb to provide a good compromise for straight line stability was 1-2 cm I believe. Effective means you need to subtract the backsweep of the handlebar since you would obviously end up with a negative lever with a 0 mm stem and a common mtb handlebar. With more modern bike geometries (shorter fork offset, slacker head angle) this may not be valid any more, as you said. Btw. the so called "Raised Reversed Stem", this crazy high short stem you may have heard of: the idea I believe is that by raising the handlebar you reduce the weight on the handlebar to moto regions. - Chainstay length. I am sure you are aware of it, but for the regular audience: please consider small bike sizes. I am currently on a bike that has a 430 mm chainstay and a 430 mm reach with a 35 mm stem (I'm only 167 cm short). This is great. Nowadays I see bikes that have 450 mm chainstays on all sizes, so you might get a 430 mm reach on small size. This sucks. Difficult to manual, bunny hop or make bike oversteer (very important to me). Just keep the 1:1 ratio between chainstay and reach. So if you have a 520 mm reach on size XL, give it a 520 mm chain stay. Crazy, I know, but it's just science.
Thanks @alexgordon8277, I'm with you on wanting a smaller bike for playfulness, ease and speed to manual, bunny hop, and to make the bike oversteer. I want to manual and bunny hop more on the trail and I have had problems with feeling that my bike understeers with a shorter stem that I have fixed with a longer one (going from 35 to 50 mm). Though, I do agree that @RULEZMANSUSPENSION has good points for stability that apply well for racing. This video generates a lot of ideas for me! For example, I think about if it is possible to make a combined linkage and shock to give a considerable rear axle path (obviously with high pivot) that has 1, plushness off the top; 2, good enough mid stroke support and LSC damping to not {considerably fall through mid stroke and lengthen chain stay with the rear axle path} when doing a bunny hop, a manual, or otherwise pushing with body weight; and 3, that reaches considerable travel through mid stroke, lengthening chain stay when hits are hard and stability is preferable. My thoughts of a shock to provide these characteristics come from the Rock Shox DJ that does just this but on a micro scale. 1, it has about a cm of plushness off the top; 2, then goes quite stiff to create a rigid feel for ultimate pumping on a pump track; and 3, when landing jumps it actually falls through travel to give exactly the support that you want. Now the question arises: Are these traits transferable to our application?
@@niklasdr "...understeers with a shorter stem that I have fixed with a longer one (going from 35 to 50 mm)." What you experienced with this was the limit of your functional Reach (as David explains above, when I say "functional"). When Reach is bigger than your posture, abilities and flexibility & reflexes allow, you can't weight the front wheel adequately. I have played around with this since before Reach was part of marketing lingo. Effective top tube measurements more or less tell you, as long as you understand your STA affects this ETT vs Reach comparison. Like David I was curious about shortening the stem and what that does to the geometry and reactivity. In the early 00s top tubes were shorter and so a shorter stem pushed you backward on the bike. What was needed was more top tube. When top tubes got longer? About the time they started talking about Reach. With more top tube and less stem, you get equal front contact patch weighting right up until you go too big on your Reach and throw off your posture & reactivity. Gary Fisher tried to make a splash with this idea, in moderated fashion, some time ago. He was suggesting moving from 100-120 stems to 70-90 stems. It didn't take at the time, but later it started catching on with bigger top tubes and shorter stems. Look at modern XC race bikes in World Cup level racing. Compare them to 20 years ago. Even the serious anaerobic athletes are benefiting from a more stable platform.
@@seanoneil277 "What you experienced with this was the limit of your functional Reach (as David explains above, when I say "functional")." You are misinterpreting me. I am talking about under- and oversteering. My case does not have to do with functional reach. I had the same functional reach in both cases. Longer frame reach and shorter stem gave me understeering. Shorter frame reach and longer stem gives me a better balance between understeering and oversteering.
@@niklasdr I may be misunderstanding you. But consider this -- under/oversteer qualities are related to this concept of what is your functional Reach. How either gets introduced into a steering effort is a combination of geometry w/in the bike itself, and the rider's fit to that bike & geometry while riding. Wouldn't you agree that you can, if skilled enough -- and if rider to bike fit is good enough, induce understeer or oversteer at will? I don't mean to suggest your skills/experience are low or inadequate. I'm just saying that from my experience, riding bicycles then motos as a kid, then again road bicycles and MTBs later as an adult, trying different frames and geometries as well as undersizing and oversizing on frames, what I've learned is that especially when oversized, a bike can feel as though it understeers more than oversteers. Conversely a too-small bike (i.e. adult on a 20" BMX) will feel always oversteering unless you grew up riding compact WB and steep angles. In between oversized and undersized is a "just right" spot where you can maneuver the bike as you wish, rather than feeling forced into passenger mode (oversized) or clown-biked (undersized). Your functional Reach is a big part of maneuvering the bike as you wish.
@@seanoneil277 You definitely have a point and I like your reasoning, I follow along on it! It's just that my case tells myself a different story as I went up in functional reach (by lengthening the stem) and found less understeering. This is a bit the opposite of your story that a longer functional reach will lead to more understeering. And it is here I mean I feel that a bit longer stem gives more of the feeling of pulling the front wheel through the corner in the direction that I want to go [giving me a balanced oversteering] as opposed to pushing it through with a risk of it washing out [understeering]. I'm a pretty normal medium size guy at 5'10 / 178 cm tall, with perhaps a little more legs than some at 32" / 82 cm inseam, and a bit longer arms than most at 6'1 / 186 cm wing span. I have loved a 27" 422 reach frame with a 50 stem. I liked a 29" 460 reach with 40 stem, even though it felt like a monster truck in comparison. And I loved straight-lining the next 29" 470 reach with a 35 stem (after not liking the 50 stem it came with because the bike felt too big). It is the next mx 455 reach with 35 stem that I felt understeered, which I felt was solved with the longer 50 stem. I now also ride a 445 reach, 50 stem bike I really like for playfulness. But I feel my best size for enduro is a 455 to 460 reach and a 42 to 50 stem. But, I am open to experimenting and finding anything new that could override what I feel is true today!
the chainstay length is quite interesting as it is more fun to have it shorter for nimble and fun rides. pop manuals from time to time and get out of corners quick.
This is why we should have sepparate bike Downhill frame designed for racing and Downhill frame designed for Freeride just like Commencal did they have 2 different DH bike
Love the content with actual math and physics to prove the point. Have you and can you create a chart with your evidence based approach on what are good reach and CS length numbers for different rider heights. That would be great.
The evidence that matters for this topic is how it rides for you. Not what calculations tell you. How it performs. Math is a tool, it is not the answer.
I look after clients since 15 years , and I can tell you most people believe they are well set, but once I revise their geo/setup they really start to shine. My task is to promote what I tested being the best, to all of you.
I have thought that short rear centres for all sizes has been wrong for some time. On my own Chameleon hardtail I extended the drops all the way to 435. No negative to my riding. I’m 164 tall too. Been on short 31mm stems too. Again, works well for me. The myth of a long front or long stem to put weight on the front wheel for climbing is so obviously wrong as you eloquently describe. No one pushes down on a bike while climbing steep bits. We pull back on the bar on steeps. And I know steeps. I live and ride in Whistler .
Wow explained in a way everyone can understand. I'm 1.98 m tall with long legs. Very happy reach is rising, but rear chains stays only a few milimeters and stack even getting shorter. Also the shrinking seat tube lengths in biggest size(very often 46cm ore less) is a concern for tall riders. To be able to use a 18mm stem I need a reach of well over 55cm. Not found yet. Fisrt time I noticed what a long chainstay and wheelbase mean was on, our tandem with 485 mm chainstays. We can climb the sky. Only disadvatge : turning circle.
Complimenti David. questo video mi conforta. io sono 176cm e su una Hightower v3 misura L. tutti mi dicono che avrei dovuto scegliere la M, anche se mi trovo molto bene con la geometria della mia L (arrivo da una Bronson v2 size M, e ho sempre avuto l'impressione che fosse piccolina per me). Ora voglio comunque adottare qualcuna delle modifiche che suggerisci in questo video e in altri (attacco più corto, sella in avanti, settaggio sospensioni). Sono sicuro che può solo migliorare. Grazie
This is super interesting, thanks for making this video. I do have a couple of questions though. How would someone go about finding what reach they should theoretically be riding? Are there any measurements we can take to help get us in a ball park? And I know you and Paul are big fans of the moto style suspension that's much stiffer and damped than what we are probably conventionally used to riding. Does this style of geometry require this style of suspension setup to work well? Cheers for the video anyway, It's really got me thinking.
our style of suspension works better on any frame, we strongly know stock stuff is badly set, no matter stem length!!! bro!!! nope, at the moment we haven’t lay down a table chart of sizes, maybe we do it in future. Personally I offer this type of thinking-helping to my clients as a package when they buy a new bike etc !
@@RULEZMANSUSPENSION ah, I was going to say this sounded like something that would go well as a packaged service. Interesting though. I'm excited to see where the industry heads towards since the past few years it seems to have settled any drastic geometry changes between models.
I like the idea of the shorter stem of 15mm. I have a husqvarna 300te and the bars are over the forks so this is agreed. If you go the short stem then we need a longer top tube. Could one change out their front triangle for the next size up do you think ?
Hi Dave, congrats for the content, but you just made me wonder a question. Why not make a stem and bar with each 0 offset instead of doing additions and teakeaways with values? Wouldn't that generate even less stress since there is no force's arm?
How about fork offset? I can buy 37mm, 42mm, 44mm or 46mm offset fork for my 27.5" enduro bike. You are correct about the 15-18mm stem lenght because the grip is going to be centered with the steerer tube and I totally agree with your view, long stems are terrible. But how about fork offset? How can I choose the correct fork offset if my handlebar is centered with the steerer tube and what effect does it have if use "shorter" or "longer" offset?
I watched the full video, thanks! I agree otherwise, but in my experience 12 degree backsweep handlebar is only good when riding bike from sitting position, but when riding from attack position, 8 degree backsweep (0 degree upsweep) handlebar is better. I've tested both backsweeps on long test periods. In attack position wrists are at more direct angle to the handlebar and upper body muscles are better activated with the 8 degree bar. It´s also easier to ride correct attack position = elbows out. Many pro downhill riders prefer fairly straight bars for this reason (such as Renthals). Also Fabio Wibmer understand this and his signature SQlab 3OX Carbon bar has only 7 degree backsweep. Motocross racers also will usually prefer a lower bar with less sweep, this keeps their body weight further forward, helping with cornering and hard acceleration. I think on a lot of mx motorcycles, handlebar grips are actually located little behind steering axis, not in line with it. Steering felt good with 32mm stem, 42mm fork offset and 8 degree bar combo on my bike, but the bar snapped recently and I had to switch to a spare bar with more backsweep. Now the steering feels way too sensitive and fast due to shorter "cantilever" with the same stem. I haven't even gotten used to it for several days. "Steering ratio" is too high, which means that front tire tends to "oversteering". I must do many steering corrections for one task on slippery surfaces, ruts, etc. Previous setup was very balanced. I use always 800mm width bars and now my grips are still 23mm front of steering axis measured in the middle of the grips. If I would use even shorter stem, wouldn't the steering of the bike become even more twitchy? Fork offset, which is also "cantilever", plays also role here and it´s 42mm on my fork and head angle is of course 63 degrees. I have tested different offsets such as 42mm, 46mm and 51mm. 42mm is the best of those. Chris Porter has experimented with a huge range of fork offsets on his bikes, and he has found that shorter offsets give a calmer handling bike, which tends to go faster when the stopwatch is brought to bear. Following this, Chris has landed on a 30mm offset for his 27,5" bike. Shorter offset also reduces the ‘floppy’ feeling that can occur when tackling tight corners, where the wheel can feel like it wants to tuck under. This is nothing to do with "trail", but simply the fact that a longer offset will put the contact patch further inside of the bike when cornering, causing it to pull to the inside of the turn. Interaction between stem cantilever and fork offset cantilever is actually quite important. Steering ratio is 1:1 when fork offset is zero and handlebar grips are in line with steering axis or if distance from steering axis is equal on both; offset and grips. As Greg Minnaar once said: "You don't want a stem any longer than the offset of your fork." Greg didn’t want a stem length too different to the offset of his fork and I can agree. If I would ride with 15mm stem, I would need also shorter than 42mm offset for the balanced steering ratio. Unfortunately, the offsets of forks on the market are too long for that. Of course bar width (cantilever) is also important factor for steering sensitivity.
You're obviously a talented engineer by solving these issues. But if the mountain bike engineers do the same today what will the bike companies sell you tomorrow?
Vorsprung has talk about ratio between front and rear axel/bottom braket Lee mackormack has a sizing rider area distance Some chooce their bike with a hypothenuse of stack and reach
Congrats on the the reall y well made video. The point that that never makes it into the discussion is the dynamic change in cs length and it's effects. A Banshee legend for example has a really long static cs but shortens a lot as it moves into it's travel. So being tall (196 cm) i sometimes wonder if the static cs length is the real info i should be looking for?
I wonder about your opinion on the stabilizing effect of a longer stem; I think 30-50mm is not uncommon stem length that's been seen around EWS and many casual riders, myself included. The issue with super short stems and narrower bars, say 760, is that the steering can become twitchy - front wheel gets deflected easier by the obstacles the front wheel hits. This can be mitigated by slightly increasing the stem length. So a longer wheelbase will not neccessarily aid in controlling wheel flop.
I built a short stem that’s about 15mm on my dh bike and it is wild how good it feels. It’s not twitchy but the steering feels faster in a very smooth and controlled way.
How does backsweep effect steering foces/input? You mentioned 9-12 degrees is ideal. Why isn't 12 degrees more popular? It seems like 8 is pretty common.
about chainstay length, I noticed many bike brands just increase the reach as you go to larger sizes, while keeping chainstay the same. That means the problem of weighing the front end only gets worse with larger sizes, so going for 1-2 sizes up doesn't mean more modern geometry. Or am I wrong somewhere?
This is the bike I have, large V3 banshee prime. It seems to crush climbs and is stable on the way down. I'm looking at trying the longer dropouts, to lengthen the chainstays 10mm, and the wheelbase as well.
Question. If a longer chainstay increases the ratio of chainstay to front center, wouldn't a shorter front end also accomplish the same thing and thus help with climbing? (of course coupled with a steep seat angle, and assuming the bike is still the right size for someone) Always appreciate your content.
@@RULEZMANSUSPENSION An easy practical lesson for the guy who asked you -- borrow some kid's 20" BMX and take it for a trail ride. See what you think about shortening either half of the WB! You get to try the shortest of all! Steepest angles too! It's a good lesson -- do your average trail loop on a road bike. On a BMX bike. On a "modern" hardtail trail bike -- rigid fork if possible, but still modern (65ish) HA. How does each behave differently and why? What does the relation of your hands to the front axle tell you as you move from bike to bike? Which bikes get chocked and stopped by rocks, roots, holes most easily? Which bikes buck you terribly in rougher surfaces?
No. A short chainstay + short front DOES the same weight on the front wheel as a long CS+ long front, because your weight When descending or cornering is vertically above the bottom bracket (you are standing). So, only the ratio between the two matters. When climbing, you are (often) seated, so you CoG moves backwards, relative to the bike. So only CS length and seat tube angle matter. For standing climbing, your hypothesis would be correct, as long as the CS remained long enough to keep the CoG in front of the rear tire contact.
I just started riding a mountain bike, coming from motorcycles. I find it infuriating that sub 20mm or even a 0 offset aren't regularly available. It may be that I'm new to a mountain bike, but the cantilever steering feels like such a garbage. I'm 5'10" on a large 18-inch frame 29er. Maybe that's my problem, but all the strange feelings are coming from the odd steering, in my opinion.
not really: the very first was mondraker back in 2012-2013 with forward geometry, gt followed a little and nicolai and pole kicked in strong. As far as today any bike can be modern for you, as long as you buy 1-2 sizes up!!!!
@@RULEZMANSUSPENSION apologies, new to your RUclips channel! I see many videos with Banshee in the title 🤣 I will be spending many more hours watching your videos
@@RULEZMANSUSPENSION might disagree with your statement that ANY bike can be modern though, many brands have stack heights coupled with chain stays that stay the same measurement/length all through size S to XL! How will I center myself on an XL bike with 520 reach but 430 chainstay?
Another thing people don't realize is how much reach you lose with riser bars. I typically lose 5 cm from the frame reach once I get bars that meet my "real stack" preference. I need bikes with 530-540mm frame reach typically.
That must mean you roll your bars back quite a lot, right? I stand my riser bar straight up and instead gain total reach. I guess there's a lot of preference differential!
@@niklasdr I'm tall (6-6) so i need a lot of height from my bars and to keep my grips in line with the head tube axis the grips end up well behind the top of the head tube. I'm not rolling back the bars though, this is just what happens when you add 10 or more cm of stack height with riser bars.
Crashing into an obstacle (the crash shown at 15:30 ) is less of an issue for 'cantilever' stems as pushing on the bars with both hands will want to straighten the bars. More so than with a zero offset stem. Regarding the torque applied to the steerer tube by the 'cantilever' stem (even the one shown in the video, never mind what's actually being run on modern bikes en masse), it's peanuts compared to what the fork is doing to the bearings, steerer tube and headtube.
you are wrong bro: to “ straighten” the bar you need strong moments each side, and strong moments are obtained with larger ARMS aka the widest distannce from center to grip , in other words the bigger is the handlebar the more easier is to counterbalance a moment of force on the steer axle.
Ciao, innanzitutto complimenti per il canale 💪🏻💪🏻 riusciresti a fare questo video in italiano o con i sottotitoli in italiano?? Non tutti sono anglofoni 😅 Grazie
You’ve sold me on a 32mm stem for my bike, just wanted to ask why people say a shorter stem results in understeer in correlation to fork offset, and how it really affects steering performance? Thanks in advance!!
@64x83 people say lot of bullshit: there is no proof of needing to match fork offset with clamp offset. the whole mtb world and forums are nonsense, go look whamotocross use if you wanna study how things should be
Correct in theory. And might work nicely. But the bike will be very long (front to rear) for this to work (assuming you want the same reach). Dont know how agile it will feel on twisty trails and going over obstacles in lower speed...
it all nice to be said and showed with pictures but is there are really telemetry prof for extremely lite hands? when i moved to longer frame it becomes easier to load front by hands, 15-20 kg is not much for trained hands also you don`t really pull bunny hops on motocross bike (without using engine) so short chainstays here to stay for playfulness of bike
First question: And what about handling tight corners? I am 189cm tall with +12cm ape index. If I put 500mm chainstay and 600mm reach with 78° STA and 64° HTA I would get around 1450mm wheelbase. Second question: If you pair 15mm stem with 63° HTA wouldn't it be too nervous? Third question: If I take 820mm 13😢° backsweep handlebar and it starts curving at 2/5 so it leaves me 3/5 ((410x(3/5))/90°)x13°=35. That means my 35mm stem will put that handlebar in alligment with fork. Is't that true?
damn, you are good in math, but real world is different: at 189cm you need 530ish reach and 680ish stack, 15mm stem, 490-500 CS, 1360ish WB, and it will be the best bike of your life.
@@RULEZMANSUSPENSION that is good for normal 189cm tall guy. Each of my arms is 6cm longer. I have 498 reach with 120mm stem, 678 stack plus 40mm spacers below stem and standard handlebar, 76° STA. Perfect fit
@@RULEZMANSUSPENSION I plan to go completly costom and make geomax bike with 1410mm wheelbase since that is the maximum without losing preformance significantly
In an ideal world wouldn't you want to create a situation where your hands are lined up with the fork axle to prevent over/under steering? And therefore have a shorter stem combined with a shorter fork offset too?
I find I want to have a little stem length to get it to steer balanced for me. With a short stem I have felt the bike is understeered. @RULEZMANSUSPENSION, maybe you have other ideas or solutions that make a bike not feel understeered for you?
@@RULEZMANSUSPENSION I would guess you suggest I go slacker head tube to get it to not feel understeered. That’s what I can think of right now. Though, I think I simply have to read in on theory what makes a vehicle more or less understeered.
eBikes now a day have involuntarily grow the CS just to fit the motor, just by concidence, 0 credits to them xD Bikes are finally getting to MX geometry. Better in every way BUT the only gripe is that on long bikes is harder to pick up the front, wich in a moto is no problem since you do it by trhotle.
multiple reasons, we have to investigate, if you pass by finale ligure give me a call and we work that out ( possible causes are: wrong size for your height, wrong suspension settings, short cs, etc )
Onoff makes the kryptom direct mount 10mm stem. Tried it a while ago on a bike with a long reach but it felt like shit. Went back to short reach, very open head angle and 50mm stem.
@@padraicbateman I am 100% sure that suspension were bad set, and chainstay and wheel base was too short. According to my tests 10 mm stem works pretty well if all other aspects are in the right spot
@@RULEZMANSUSPENSION Reach and chainstays were roughly simillar (r: 445 - cs: 435). I'm quite a perfectionist so I do a lot of bracketing in different locations till I find the best compromise or rather a usable range. At the same time I was testing with the fork offset, so used the 10mm stem on a Chris Porter Morc 36 (Fox 36 lowers converted to dual crown), that allowed me to make a lot of testing over 3 months to find the best setup. Morc uses Formula dual chamber air coil, not the best but still managed to get it pretty dialed. On the rear I was using a kitsuma coil which had to revalve to my weight due to too much rebound damping from stock. In all honesty, it didn't feel like bad everywhere. Natural trails or more rough enduro style felt pretty good but bikepark style felt terrible.
Sounds amazing! would you like to do a podcast video for the Israeli audience as well? Plus, can you touch base on the logic for XC based bikes and not only DH/Enduro ones?
Hi Dave, good video. Do you intend to do a more in depth video presenting more complicated mechanics? The general idea is there and your message and assumptions seems sound but I personally would appreciate at least one level deeper - especially for thesis' like the lack of effect (or significance) of forces through the arms/hands or your statement that zero length stem does not cause bending forces to the fork. Also how do you come the right geometry figures? what is the connection to human biomechanics ( or putting it more simply - why not 600mm chain stay?) do you have a white paper that you could share of your calculations? I would certainly enjoy reading.
I have other films and videos planned, no time to go deeper even because 98% of people would be just bored by the tech. If you pass by finale ligure you are welcome to come and talk directly with myself on any topic.
I really like this presentation. I have a hard time with long CS unless I have a motor propelling the rear wheel and can change turn radius with throttle. On a MTB, long CS just opens up the needed turn radius for a given turn, and/or requires you to square the turn w/o throttle, or do a nose pivot to bring the rear wheel around. The grip is incredible, yes. But the maneuverability suffers for me.
each one can buy/usw what suit him the best: myself and Aston can not ride short bikes any longer and we are totally convinced the whole mtb world still has to grow in size! btw.. I rode motos for 30 years but CS on my hondas cr… was Way Longer than stupid mtb 430mm 😂😂
@@RULEZMANSUSPENSION It takes at least different skills, if not higher levels of skill, to ride a long CS bike in places with tight corners. In some situations you can set up the turn and it doesn't feel horrible to me, but I've ridden trails that force me to get off the bike when the CS is too long and my skills can't bring it around. I can imagine that if I could ride with more trials skill it would be appealing. But I still think of it like skis, you can have small R slalom skis, mid R GS skis big R SG/DH skis. At one end of the spectrum the turn almost begins itself; at the other end you must have speed to get the ski to begin a turn, or if slow you need lots of room to initiate the turn. Or a slash to start the turn.
@@seanoneil277 yeah, makes sense: the main point to me is that everyone is timing their runs downhill (enduro or dh no matter), averaging a speed of 25-30 km/h, this means to me that the speed is HIGH, and this means we need long CS / WB bikes. For sure to go at 4 ..6...8 k/h and making trials and tight trails, a bike with 26" wheels and 410 CS and 1050 WB would be 10000 times better than a bike made to keep that 30 km/h average in a easier way. My goal is to make bikes to go FAST and with less effort. I am not here to do trials.
@@RULEZMANSUSPENSION Modern UCI World Cup tracks are super high speed compared to 20 yrs ago. If I rode at that level I would want (I think, from my piker's perspective) a relatively ground-hugging suspension and geometry like what you're talking about. When I watch World Cup DH, I'm always noticing Loic Bruni's stability and smoothness and that's what I'd be aiming toward. The tight corners of a place like Schladming would take a lot of work, but I say that as a piker not a top-level rider. They probably adapt as easily as anyone could.
@seanoneil277 Loic Bruni admitted that he is old school with his bike setup he runs really short, The reason why he can ride it because his body strength can handle the bike. Compare it to Jackson Goldstone he rides very different compared to Loic he has long wheelbase and high stack by just looking at his stature, look at Assa vermette he also rides long wheelbase since he was smaller and younger.
Thanks for a great video with clear explanations! What are your thoughts on RAD (Rider Area Distance) measurement for bike sizing? I've seen a couple of videos where it's claimed to be a good measurement to properly size your bike (e.g. ruclips.net/video/rHagRovHSYs/видео.html, ruclips.net/video/SnXe2RmxKr/видео.html), but it seems to lean you towards slightly smaller sizes, where you recommendations seem to lean towards larger sizes. Grazie! 🙏
RAD? stupid nonsense: RAD IS a distance without an angle and wont tell you the exact point in the space of where your bar is, while real reach and real stack ARE LIKE XY coords for your target: this is geometry bro. 1 distance without an angle tells you nothing.
@@RULEZMANSUSPENSION Exactly. I tried saying it to Lee, but he didn't care. Than the concept of RAAD came into play which makes no actual inputs. Even short stem can be controlled, that's exactly why old bikes with long stems disappear.
yes, they probably saw my stuff in 2010 and maybe copied the idea 😂 .. yeah I liked their stuff but I never arrived to BUY IT NOW LEVEL myself since I can not use my handlebars on their stems,.
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Very enlightening, And it makes perfect sense when you explain it. Thank you. I learnt a lot 👍
Love you and thank you. Finally an intelligent mind within the industry, I hope people appreciate you and your valuable knowledges. I watch all of your videos and inventions. Guys like you make the World a better place to live in it by having true knowledge. Much much appreciated.❤
Nice interesting video, thx for making it in english for non italian watchers!❤
Fantastic info and so well presented 👍Unfortunately, most don't have a choice and go with the current trend / industry offerings.
Also, re: rear stay lengths - it's fascinating how the same stay length can be used across all sizes offered, I'm using Spec Chisel as an example: same 432mm from size small to XL - meaning weight distribution variation @ BB almost 4% depending on the size!
Great video Dave 👍
Totally agree on all your points. Thanks for sharing 😊
Awesome truth! Thanks for sharing this information with fellow bike lovers.
Your doing gods work Dave! ❤ I really liked that you gave us some numbers to look out for. Im asking myself about other factors like stack, bb height etc... i know Aston made a video about his bike going a little into it, but i would love to see one of you two (or maybe even both) give us some tips to find the right geo bike or even to get a custom one build. Thank you alot for sharing your knowledge 🤟👍
It will come
Many thanks for this very explanatory video. A master pièce of explanation demonstrating the vast majority of the bike industry looks like a the fashion industry.
TRUE words bro.
This is very educational and crystal clear to understand!
Cheers mate! ✌️✌️✌️
Glad you enjoyed it!
Thank You for sharing this magic. Very informative video!
My pleasure!
Great video! Thanks for sharing.
Thanks for watching!
always loved a short or direct stem, but never realized the chainstay. Great point
Thanks for watching!
Hi Dave, congrats for the video.
I have a 470mm chainstay, 500mm reach, 1320mm wheelbase custom made hardtail bike (I'm 180cm tall), and couldn't agree more with you.
In my opinion, the only downsides in comparison with a "traditional" bike are:
- more side lean is needed to corner on very twisty, old school trails; therefore, switching between consecutive turns needs a lot of aggression;
- the added front wheel loading makes intentionally lifting the front wheel over obstacles quite harder.
Now I'm going to experiment with mullet set-up and higher rise handlebars.
Happy Christmas holidays!
yeah , nice comment man! 🤝
awesome video, very interesting!!!
Longer rear end = more front grip. Makes total sense when explained by a real engineer 👏
thanks man !🤝
@@RULEZMANSUSPENSION I do agree with the sentiment but a 460 CS on a 1300 WB bike gives the rear 35% of the complete wheelbase and 480 CS a 37%.
How long chainstays are you saying you want? a 440 CS on a 1240 WB bike gives just over 35% ratio of WB as well.
@@javisst44 nice calcs bro. 🎖: MOST MODERN adult bikes are 1280-1300 and still retain 430-435-440 CS, while we should move to 460-480 range . 1240? wow what is that a kid’s bike? yes, that cS is well proportioned for such short wb
So is there a front center to rear center ratio you like. My bike at static has a 1.8 ratio and it corners quite well, but I think it could corner even better
Yo man! Awesome video I see why now you ride banshee bikes. The geometry on their bikes are good. I am 6’1 185cm I ordered a titan in XL I see now the “bigger head tube” “longer chainstay than other bikes and high stack. Higher bb it makes sense! I am glad to have bought this bike I cannot wait to build it up and ride it
add the ZEROBACK plate to it and some RRT suspension and you ll be well set !
@@RULEZMANSUSPENSION hahah I wish I could with the RRT suspension I am swapping a lot of my stuff from my meta. And just like you said I am struggling with that bike with the long reach and shorter chainstay!
And what’s the zero back plate?
Love it
Fantastic video thanks! A big difference between motos and bikes is the rider is an essential handling piece as the system center of gravity can be changed much more than a motorbike. How do you view the effects your ideal setup would have on jumping via 1: build ramp and 2: bunny hopping? 1 a moto can do but 2 is unique to bicycles.
not really… trials riders bunny hop trial bikes too using suspension force and engine rev: moto is just 100 times more difficult
I have been saying this since the early 2000s! I currently run 35mm stems, but I would love a 15mm stem. I don't see anywhere I can get one though.
As for chainstay length, a shorter chainstay gives a bike more pop for jumping. Longer chainstays make pulling up the front wheel more challenging and because many riders like the catch air a short chainstay makes that a lot easier. Comparing a motocross bikes chainstay to a bicycle is a bit odd considering you have a motor with a bunch of power to get the front end up, something you don't have for a mountain bike. On a bicycle you have to control the pitch of the bike with your arms, legs, and body position. So I am not so sure I agree on your statements about making chainstay lengths longer simply for more equal front real balance during cornering. You do a lot more on a mountain bike that cornering so the frame geometry needs to be well balanced to accommodate all the different situations. So for my height of 5' 7" anyway, a 435 - 440mm chainstay is perfect. As a rider gets taller, the chainstay length should get longer, not just the front of the bike.
15mm stem: email me. I produce them.
CS: races are win on corners not on hopping, and long cs makes you cornering with more speed overall, so it is faster. who think at hop as his first passion shoul
buy a 24” bike or dirt jump
@@RULEZMANSUSPENSION Sure, for racing. Most of us just ride for fun and enjoyment. And yes, we still want higher performing full suspension or hardtail bikes. A DJ bike won't be very fun to ride on most singletrack. I don't want every manufacturer to design every regular consumer bike for what the highest level racers need.
Most lift access trails and flow trails have jumps and fun features in them, think freeride. I think one of the biggest problems in the bike industry is they have racers determine what everyone else should be riding. Maybe the term freeride needs to come back and Enduro can be the racers bike with long chainstays, super slack head angles, and so on. I absolutely agree with you about the stem though.
And yes, I will contact you about that stem. ✌️
My second DH Bike was an YT tues vor 15 years. While i have No Money i buy it in Large but i am only 1.70. than i Put the on Off stem from the Mondraker on it. All Guys laught but that was the Best.
DO YOUR THING BRO, RESPECT TO SELF-THINKERS 🏆
@@RULEZMANSUSPENSION
Yes i come also from car Mechanik.
And i also think what the fuck are there doing with the Bike Geometrie
Im currently puzzling with bars that are comfortable for me so I have round 7 different ones at home. I measured them all and one thing I noted is that they very strongly differ in how much they reduce the Reach. E.g the ergotec with 12deg reduced reach by 70mm. The SQlab with 12deg however only 35mm and the FAST flex one sits somewhere in between. All other bars with 6deg (Renthal) or 9deg (Nukeproof) sit in between. Its really mad. I guess that should be added to the equation of correct stem length because with that Ergotec my 40mm Stem is effectively Zero offset - and it feels great :)
you are not uptiltinf handlebars up by 5 degrees to follow natural hands contour, as well you are probably ( I guess) measuring end to end, while in reality the line should be drew from about 7 cm inside each hand of the handlebar. ANYWAY: 7 bars at home, My compliments, you invest a lot bro
Complimenti per le spiegazioni chiarissime. Una domanda: tu
Dici che preferisci le taglie XL ma in realtà la maggior parte delle case usa le stesse proporzioni per tutte le taglie. Quindi prendendo una taglia più grande si andrebbe a peggiorare la posizione del Cg. Mi pare che ad oggi qualche casa propone chain stay “ tailored” per ogni taglia. Si potrebbe avere quindi un miglioramento.
Dimmi se il mio ragionamento è giusto e cosa ne pensi.
Grazie mille!
Lo dico esattamente nel mio tech video.
A BBSHD ! I got no probs large chain stay ! Hard to even lift the front wheel on a hill ! Large frame full suspension ! 730 handlebars !
Hey Rulezman, geat video, thanks. I'd like to comment on two things.
- Moto vs bicycle. I read an article by someone from Mondraker a while ago on why they abandoned the 0 mm stems and why it works on moto. The deal (as far I can remember) was that on moto the whole system is way heavier and more stable and therefore does not rely on the stabilizing effect of the cantilever (stem) while going straight. Therefore even negative stem length works on moto that would destabilize the ride. Mondraker figured out that the optimal effective lever for mtb to provide a good compromise for straight line stability was 1-2 cm I believe. Effective means you need to subtract the backsweep of the handlebar since you would obviously end up with a negative lever with a 0 mm stem and a common mtb handlebar. With more modern bike geometries (shorter fork offset, slacker head angle) this may not be valid any more, as you said. Btw. the so called "Raised Reversed Stem", this crazy high short stem you may have heard of: the idea I believe is that by raising the handlebar you reduce the weight on the handlebar to moto regions.
- Chainstay length. I am sure you are aware of it, but for the regular audience: please consider small bike sizes. I am currently on a bike that has a 430 mm chainstay and a 430 mm reach with a 35 mm stem (I'm only 167 cm short). This is great. Nowadays I see bikes that have 450 mm chainstays on all sizes, so you might get a 430 mm reach on small size. This sucks. Difficult to manual, bunny hop or make bike oversteer (very important to me). Just keep the 1:1 ratio between chainstay and reach. So if you have a 520 mm reach on size XL, give it a 520 mm chain stay. Crazy, I know, but it's just science.
Thanks @alexgordon8277, I'm with you on wanting a smaller bike for playfulness, ease and speed to manual, bunny hop, and to make the bike oversteer. I want to manual and bunny hop more on the trail and I have had problems with feeling that my bike understeers with a shorter stem that I have fixed with a longer one (going from 35 to 50 mm).
Though, I do agree that @RULEZMANSUSPENSION has good points for stability that apply well for racing.
This video generates a lot of ideas for me!
For example, I think about if it is possible to make a combined linkage and shock to give a considerable rear axle path (obviously with high pivot) that has 1, plushness off the top; 2, good enough mid stroke support and LSC damping to not {considerably fall through mid stroke and lengthen chain stay with the rear axle path} when doing a bunny hop, a manual, or otherwise pushing with body weight; and 3, that reaches considerable travel through mid stroke, lengthening chain stay when hits are hard and stability is preferable.
My thoughts of a shock to provide these characteristics come from the Rock Shox DJ that does just this but on a micro scale. 1, it has about a cm of plushness off the top; 2, then goes quite stiff to create a rigid feel for ultimate pumping on a pump track; and 3, when landing jumps it actually falls through travel to give exactly the support that you want.
Now the question arises: Are these traits transferable to our application?
@@niklasdr "...understeers with a shorter stem that I have fixed with a longer one (going from 35 to 50 mm)."
What you experienced with this was the limit of your functional Reach (as David explains above, when I say "functional"). When Reach is bigger than your posture, abilities and flexibility & reflexes allow, you can't weight the front wheel adequately.
I have played around with this since before Reach was part of marketing lingo. Effective top tube measurements more or less tell you, as long as you understand your STA affects this ETT vs Reach comparison. Like David I was curious about shortening the stem and what that does to the geometry and reactivity. In the early 00s top tubes were shorter and so a shorter stem pushed you backward on the bike. What was needed was more top tube. When top tubes got longer? About the time they started talking about Reach. With more top tube and less stem, you get equal front contact patch weighting right up until you go too big on your Reach and throw off your posture & reactivity.
Gary Fisher tried to make a splash with this idea, in moderated fashion, some time ago. He was suggesting moving from 100-120 stems to 70-90 stems. It didn't take at the time, but later it started catching on with bigger top tubes and shorter stems. Look at modern XC race bikes in World Cup level racing. Compare them to 20 years ago. Even the serious anaerobic athletes are benefiting from a more stable platform.
@@seanoneil277 "What you experienced with this was the limit of your functional Reach (as David explains above, when I say "functional")." You are misinterpreting me. I am talking about under- and oversteering. My case does not have to do with functional reach. I had the same functional reach in both cases.
Longer frame reach and shorter stem gave me understeering.
Shorter frame reach and longer stem gives me a better balance between understeering and oversteering.
@@niklasdr I may be misunderstanding you. But consider this -- under/oversteer qualities are related to this concept of what is your functional Reach. How either gets introduced into a steering effort is a combination of geometry w/in the bike itself, and the rider's fit to that bike & geometry while riding. Wouldn't you agree that you can, if skilled enough -- and if rider to bike fit is good enough, induce understeer or oversteer at will?
I don't mean to suggest your skills/experience are low or inadequate. I'm just saying that from my experience, riding bicycles then motos as a kid, then again road bicycles and MTBs later as an adult, trying different frames and geometries as well as undersizing and oversizing on frames, what I've learned is that especially when oversized, a bike can feel as though it understeers more than oversteers. Conversely a too-small bike (i.e. adult on a 20" BMX) will feel always oversteering unless you grew up riding compact WB and steep angles.
In between oversized and undersized is a "just right" spot where you can maneuver the bike as you wish, rather than feeling forced into passenger mode (oversized) or clown-biked (undersized). Your functional Reach is a big part of maneuvering the bike as you wish.
@@seanoneil277 You definitely have a point and I like your reasoning, I follow along on it!
It's just that my case tells myself a different story as I went up in functional reach (by lengthening the stem) and found less understeering. This is a bit the opposite of your story that a longer functional reach will lead to more understeering. And it is here I mean I feel that a bit longer stem gives more of the feeling of pulling the front wheel through the corner in the direction that I want to go [giving me a balanced oversteering] as opposed to pushing it through with a risk of it washing out [understeering].
I'm a pretty normal medium size guy at 5'10 / 178 cm tall, with perhaps a little more legs than some at 32" / 82 cm inseam, and a bit longer arms than most at 6'1 / 186 cm wing span. I have loved a 27" 422 reach frame with a 50 stem. I liked a 29" 460 reach with 40 stem, even though it felt like a monster truck in comparison. And I loved straight-lining the next 29" 470 reach with a 35 stem (after not liking the 50 stem it came with because the bike felt too big). It is the next mx 455 reach with 35 stem that I felt understeered, which I felt was solved with the longer 50 stem. I now also ride a 445 reach, 50 stem bike I really like for playfulness. But I feel my best size for enduro is a 455 to 460 reach and a 42 to 50 stem. But, I am open to experimenting and finding anything new that could override what I feel is true today!
the chainstay length is quite interesting as it is more fun to have it shorter for nimble and fun rides. pop manuals from time to time and get out of corners quick.
NOT FOR ME: I have more fun with 500 cs than 400.
I think the only valid reason to have shorter chainstays is for wheelie and manual. but that's not really the reason I'd buy an Enduro MTB anyway...
@@allseasons765 Short chainstay is easier to bunny hop over rocks,roots and gaps so it can save time in a race but depends on the track.
This is why we should have sepparate bike
Downhill frame designed for racing and Downhill frame designed for Freeride just like Commencal did they have 2 different DH bike
Love the content with actual math and physics to prove the point. Have you and can you create a chart with your evidence based approach on what are good reach and CS length numbers for different rider heights. That would be great.
The evidence that matters for this topic is how it rides for you. Not what calculations tell you. How it performs. Math is a tool, it is not the answer.
I look after clients since 15 years , and I can tell you most people believe they are well set, but once I revise their geo/setup they really start to shine. My task is to promote what I tested being the best, to all of you.
I have thought that short rear centres for all sizes has been wrong for some time. On my own Chameleon hardtail I extended the drops all the way to 435. No negative to my riding. I’m 164 tall too. Been on short 31mm stems too. Again, works well for me. The myth of a long front or long stem to put weight on the front wheel for climbing is so obviously wrong as you eloquently describe. No one pushes down on a bike while climbing steep bits. We pull back on the bar on steeps. And I know steeps. I live and ride in Whistler .
bro: hard tails are not the right vehicles for offroad by phisycs.
@@RULEZMANSUSPENSION it’s not about being the right vehicle sometimes but the most fun.
Wow explained in a way everyone can understand. I'm 1.98 m tall with long legs. Very happy reach is rising, but rear chains stays only a few milimeters and stack even getting shorter. Also the shrinking seat tube lengths in biggest size(very often 46cm ore less) is a concern for tall riders. To be able to use a 18mm stem I need a reach of well over 55cm. Not found yet. Fisrt time I noticed what a long chainstay and wheelbase mean was on, our tandem with 485 mm chainstays. We can climb the sky. Only disadvatge : turning circle.
Complimenti David. questo video mi conforta. io sono 176cm e su una Hightower v3 misura L. tutti mi dicono che avrei dovuto scegliere la M, anche se mi trovo molto bene con la geometria della mia L (arrivo da una Bronson v2 size M, e ho sempre avuto l'impressione che fosse piccolina per me). Ora voglio comunque adottare qualcuna delle modifiche che suggerisci in questo video e in altri (attacco più corto, sella in avanti, settaggio sospensioni). Sono sicuro che può solo migliorare. Grazie
grande! fregatene di quello che dicono degli incompetebti lobotomizzati
Good video. Geometron has always kept the chainstays in proportion to the front centres.
big respect for mr Porter! for sure one of the very few innovators on planet.
This is super interesting, thanks for making this video. I do have a couple of questions though. How would someone go about finding what reach they should theoretically be riding? Are there any measurements we can take to help get us in a ball park? And I know you and Paul are big fans of the moto style suspension that's much stiffer and damped than what we are probably conventionally used to riding. Does this style of geometry require this style of suspension setup to work well?
Cheers for the video anyway, It's really got me thinking.
our style of suspension works better on any frame, we strongly know stock stuff is badly set, no matter stem length!!! bro!!! nope, at the moment we haven’t lay down a table chart of sizes, maybe we do it in future. Personally I offer this type of thinking-helping to my clients as a package when they buy a new bike etc !
@@RULEZMANSUSPENSION ah, I was going to say this sounded like something that would go well as a packaged service. Interesting though. I'm excited to see where the industry heads towards since the past few years it seems to have settled any drastic geometry changes between models.
@@swankysnail nothing will change until the sales of actual Crap slows down
I like the idea of the shorter stem of 15mm. I have a husqvarna 300te and the bars are over the forks so this is agreed. If you go the short stem then we need a longer top tube. Could one change out their front triangle for the next size up do you think ?
Hi Dave, congrats for the content, but you just made me wonder a question. Why not make a stem and bar with each 0 offset instead of doing additions and teakeaways with values?
Wouldn't that generate even less stress since there is no force's arm?
You need backsweep on the handlebars for ergonomic reasons. Without the offset the hands would be behind the steerer tube.
A STRAIGHT POLE WILL BE NOT GOOD FOR BIOMECHANICS ( in other words it will fucks up your wrists)
How about fork offset? I can buy 37mm, 42mm, 44mm or 46mm offset fork for my 27.5" enduro bike.
You are correct about the 15-18mm stem lenght because the grip is going to be centered with the steerer tube and I totally agree with your view, long stems are terrible. But how about fork offset? How can I choose the correct fork offset if my handlebar is centered with the steerer tube and what effect does it have if use "shorter" or "longer" offset?
the shortest you can get. PERIOD .
@@RULEZMANSUSPENSION You love the purest, cleanest (physics-wise) steering possible. Fewest outside inputs. Am I right?
@@RULEZMANSUSPENSION shortest fork offset?
Where should I go to learn more on how wide I should keep my bars at?
👍👍👍👍
I watched the full video, thanks! I agree otherwise, but in my experience 12 degree backsweep handlebar is only good when riding bike from sitting position, but when riding from attack position, 8 degree backsweep (0 degree upsweep) handlebar is better. I've tested both backsweeps on long test periods. In attack position wrists are at more direct angle to the handlebar and upper body muscles are better activated with the 8 degree bar. It´s also easier to ride correct attack position = elbows out. Many pro downhill riders prefer fairly straight bars for this reason (such as Renthals). Also Fabio Wibmer understand this and his signature SQlab 3OX Carbon bar has only 7 degree backsweep. Motocross racers also will usually prefer a lower bar with less sweep, this keeps their body weight further forward, helping with cornering and hard acceleration. I think on a lot of mx motorcycles, handlebar grips are actually located little behind steering axis, not in line with it.
Steering felt good with 32mm stem, 42mm fork offset and 8 degree bar combo on my bike, but the bar snapped recently and I had to switch to a spare bar with more backsweep. Now the steering feels way too sensitive and fast due to shorter "cantilever" with the same stem. I haven't even gotten used to it for several days. "Steering ratio" is too high, which means that front tire tends to "oversteering". I must do many steering corrections for one task on slippery surfaces, ruts, etc. Previous setup was very balanced. I use always 800mm width bars and now my grips are still 23mm front of steering axis measured in the middle of the grips. If I would use even shorter stem, wouldn't the steering of the bike become even more twitchy?
Fork offset, which is also "cantilever", plays also role here and it´s 42mm on my fork and head angle is of course 63 degrees. I have tested different offsets such as 42mm, 46mm and 51mm. 42mm is the best of those. Chris Porter has experimented with a huge range of fork offsets on his bikes, and he has found that shorter offsets give a calmer handling bike, which tends to go faster when the stopwatch is brought to bear. Following this, Chris has landed on a 30mm offset for his 27,5" bike. Shorter offset also reduces the ‘floppy’ feeling that can occur when tackling tight corners, where the wheel can feel like it wants to tuck under. This is nothing to do with "trail", but simply the fact that a longer offset will put the contact patch further inside of the bike when cornering, causing it to pull to the inside of the turn. Interaction between stem cantilever and fork offset cantilever is actually quite important. Steering ratio is 1:1 when fork offset is zero and handlebar grips are in line with steering axis or if distance from steering axis is equal on both; offset and grips. As Greg Minnaar once said: "You don't want a stem any longer than the offset of your fork." Greg didn’t want a stem length too different to the offset of his fork and I can agree. If I would ride with 15mm stem, I would need also shorter than 42mm offset for the balanced steering ratio. Unfortunately, the offsets of forks on the market are too long for that. Of course bar width (cantilever) is also important factor for steering sensitivity.
You're obviously a talented engineer by solving these issues. But if the mountain bike engineers do the same today what will the bike companies sell you tomorrow?
they will sale bad copy cina o taiwan crap for 15 usd ….clamps.
Vorsprung has talk about ratio between front and rear axel/bottom braket
Lee mackormack has a sizing rider area distance
Some chooce their bike with a hypothenuse of stack and reach
I did not knew about their talk, but glad I am not the only one on this topic!
Congrats on the the reall y well made video. The point that that never makes it into the discussion is the dynamic change in cs length and it's effects. A Banshee legend for example has a really long static cs but shortens a lot as it moves into it's travel. So being tall (196 cm) i sometimes wonder if the static cs length is the real info i should be looking for?
frankly speaking , at 196 cm you should look at get a custom frame with 550 reach and 700 stack or more, 1400 WB, 500 CS or more.
@@RULEZMANSUSPENSION yeah ,i'm already on a g1 but i could really Imagine the CS to be even longer.
I wonder about your opinion on the stabilizing effect of a longer stem; I think 30-50mm is not uncommon stem length that's been seen around EWS and many casual riders, myself included.
The issue with super short stems and narrower bars, say 760, is that the steering can become twitchy - front wheel gets deflected easier by the obstacles the front wheel hits. This can be mitigated by slightly increasing the stem length. So a longer wheelbase will not neccessarily aid in controlling wheel flop.
my opinion? NOTHING RIDES BETTER THAN LONG WHEELBASE BIKE, LONG CHAINSTAY , AND 15-18mm STEM.
@@RULEZMANSUSPENSION Yes, I understand that, as claimed in your video, but you haven't really ellaborated on my proposed issue of your argument.
I built a short stem that’s about 15mm on my dh bike and it is wild how good it feels. It’s not twitchy but the steering feels faster in a very smooth and controlled way.
good boy! 🎖
In this case change the angle of the headset bearing ( i.e with works 1-2 degree angleset ) to slacken bike out which will make bike less twitchy
How does backsweep effect steering foces/input? You mentioned 9-12 degrees is ideal. Why isn't 12 degrees more popular? It seems like 8 is pretty common.
because mtb are stuck on old concepts, and because 8 is cheaper to make
about chainstay length, I noticed many bike brands just increase the reach as you go to larger sizes, while keeping chainstay the same. That means the problem of weighing the front end only gets worse with larger sizes, so going for 1-2 sizes up doesn't mean more modern geometry. Or am I wrong somewhere?
you did not listen/watched my full video. This is what I said.
Do you have a recommended optimal range for chainstay to wheelbase ratio? Quick point of reference: Banshee Prime large 450/1250 is a .36 ratio.
This is the bike I have, large V3 banshee prime. It seems to crush climbs and is stable on the way down. I'm looking at trying the longer dropouts, to lengthen the chainstays 10mm, and the wheelbase as well.
Question. If a longer chainstay increases the ratio of chainstay to front center, wouldn't a shorter front end also accomplish the same thing and thus help with climbing? (of course coupled with a steep seat angle, and assuming the bike is still the right size for someone) Always appreciate your content.
a short bike is crap bro. ….forget to shorten things.
@@RULEZMANSUSPENSION An easy practical lesson for the guy who asked you -- borrow some kid's 20" BMX and take it for a trail ride. See what you think about shortening either half of the WB! You get to try the shortest of all! Steepest angles too!
It's a good lesson -- do your average trail loop on a road bike. On a BMX bike. On a "modern" hardtail trail bike -- rigid fork if possible, but still modern (65ish) HA. How does each behave differently and why? What does the relation of your hands to the front axle tell you as you move from bike to bike? Which bikes get chocked and stopped by rocks, roots, holes most easily? Which bikes buck you terribly in rougher surfaces?
No. A short chainstay + short front DOES the same weight on the front wheel as a long CS+ long front, because your weight When descending or cornering is vertically above the bottom bracket (you are standing). So, only the ratio between the two matters.
When climbing, you are (often) seated, so you CoG moves backwards, relative to the bike. So only CS length and seat tube angle matter.
For standing climbing, your hypothesis would be correct, as long as the CS remained long enough to keep the CoG in front of the rear tire contact.
@@tjb8841 Well, all your text means you have not watched and or understood what I said in the video, which is actually the same you have written. 🤝
Great explanations! Where can I find a bike frame with suitable geo for a guy 184 cm tall?
probably some brand XL would suit! you are not so tall! from 186-7 and up we start to have problems
I just started riding a mountain bike, coming from motorcycles. I find it infuriating that sub 20mm or even a 0 offset aren't regularly available. It may be that I'm new to a mountain bike, but the cantilever steering feels like such a garbage. I'm 5'10" on a large 18-inch frame 29er. Maybe that's my problem, but all the strange feelings are coming from the odd steering, in my opinion.
Very interesting video. I think the only bike manufacturer with modern geometry today is Nicolai bikes.
not really: the very first was mondraker back in 2012-2013 with forward geometry, gt followed a little and nicolai and pole kicked in strong. As far as today any bike can be modern for you, as long as you buy 1-2 sizes up!!!!
Take a look at Banshee also, they have tall head stacks and long chain stays.
@@kevinxodemonth take a look at my other videos 😂
@@RULEZMANSUSPENSION apologies, new to your RUclips channel! I see many videos with Banshee in the title 🤣 I will be spending many more hours watching your videos
@@RULEZMANSUSPENSION might disagree with your statement that ANY bike can be modern though, many brands have stack heights coupled with chain stays that stay the same measurement/length all through size S to XL! How will I center myself on an XL bike with 520 reach but 430 chainstay?
This (your) stem brings the handlebar higher up. Does this mean I'll need a handlebar with less rise?
you need to get your grips around 111-113 from ground, if BB is 34-35 cm…. use the required rise to get this
what about with long or short chainstai on downhill bike? what is better and why? you forget that on the video
I did not. Long is better
Another thing people don't realize is how much reach you lose with riser bars. I typically lose 5 cm from the frame reach once I get bars that meet my "real stack" preference. I need bikes with 530-540mm frame reach typically.
CORRECT 🎖! this is why I always buy XL frames for my 179 cm heigth !!!
That must mean you roll your bars back quite a lot, right? I stand my riser bar straight up and instead gain total reach. I guess there's a lot of preference differential!
@@niklasdr I'm tall (6-6) so i need a lot of height from my bars and to keep my grips in line with the head tube axis the grips end up well behind the top of the head tube. I'm not rolling back the bars though, this is just what happens when you add 10 or more cm of stack height with riser bars.
Crashing into an obstacle (the crash shown at 15:30 ) is less of an issue for 'cantilever' stems as pushing on the bars with both hands will want to straighten the bars. More so than with a zero offset stem.
Regarding the torque applied to the steerer tube by the 'cantilever' stem (even the one shown in the video, never mind what's actually being run on modern bikes en masse), it's peanuts compared to what the fork is doing to the bearings, steerer tube and headtube.
you are wrong bro: to “ straighten” the bar you need strong moments each side, and strong moments are obtained with larger ARMS aka the widest distannce from center to grip , in other words the bigger is the handlebar the more easier is to counterbalance a moment of force on the steer axle.
Ciao, innanzitutto complimenti per il canale 💪🏻💪🏻 riusciresti a fare questo video in italiano o con i sottotitoli in italiano?? Non tutti sono anglofoni 😅 Grazie
You’ve sold me on a 32mm stem for my bike, just wanted to ask why people say a shorter stem results in understeer in correlation to fork offset, and how it really affects steering performance? Thanks in advance!!
32 is not ideal. the correct number is 15 matched with proper geos.
ok sure 15, understood. But you still haven't answered my question...
@64x83 people say lot of bullshit: there is no proof of needing to match fork offset with clamp offset. the whole mtb world and forums are nonsense, go look whamotocross use if you wanna study how things should be
You mention back and up sweep? how about bar rise? what do you recommend/ride?
the required one to put your grips at the correct height: about 112-113 for a 180cm man.
@@RULEZMANSUSPENSION is there a ratio for this 112cm bar height : wheelbase ?
Correct in theory. And might work nicely. But the bike will be very long (front to rear) for this to work (assuming you want the same reach). Dont know how agile it will feel on twisty trails and going over obstacles in lower speed...
I make enduro and downhill bikes: the average speed on descent is about 27-31 km/h. for obstacles I use a trial bike.
@@RULEZMANSUSPENSION OK, then I agree that it will work. Will be very stable in high speed.. :-)
it all nice to be said and showed with pictures but is there are really telemetry prof for extremely lite hands? when i moved to longer frame it becomes easier to load front by hands, 15-20 kg is not much for trained hands
also you don`t really pull bunny hops on motocross bike (without using engine) so short chainstays here to stay for playfulness of bike
First question:
And what about handling tight corners?
I am 189cm tall with +12cm ape index.
If I put 500mm chainstay and 600mm reach with 78° STA and 64° HTA I would get around 1450mm wheelbase.
Second question:
If you pair 15mm stem with 63° HTA wouldn't it be too nervous?
Third question:
If I take 820mm 13😢° backsweep handlebar and it starts curving at 2/5 so it leaves me 3/5 ((410x(3/5))/90°)x13°=35.
That means my 35mm stem will put that handlebar in alligment with fork. Is't that true?
damn, you are good in math, but real world is different: at 189cm you need 530ish reach and 680ish stack, 15mm stem, 490-500 CS, 1360ish WB, and it will be the best bike of your life.
@@RULEZMANSUSPENSION that is good for normal 189cm tall guy. Each of my arms is 6cm longer. I have 498 reach with 120mm stem, 678 stack plus 40mm spacers below stem and standard handlebar, 76° STA. Perfect fit
@@RULEZMANSUSPENSION I plan to go completly costom and make geomax bike with 1410mm wheelbase since that is the maximum without losing preformance significantly
I use 12 degree backsweep 40mm rise with a 40mm stem . Effective stem length is now arroumd 0 . / frame is long xl honzo 510mm reach
with 40mmm stem and 12 back, there is no way your hands rotate around steer axle. you are about 15 mm forward.
In an ideal world wouldn't you want to create a situation where your hands are lined up with the fork axle to prevent over/under steering? And therefore have a shorter stem combined with a shorter fork offset too?
Negative. you want arms aligned with steer tube as per explanations in the video, did you watched the whole 35 min?
I find I want to have a little stem length to get it to steer balanced for me. With a short stem I have felt the bike is understeered. @RULEZMANSUSPENSION, maybe you have other ideas or solutions that make a bike not feel understeered for you?
@@niklasdr invest in pro bike setting service.
@@RULEZMANSUSPENSION I would guess you suggest I go slacker head tube to get it to not feel understeered. That’s what I can think of right now.
Though, I think I simply have to read in on theory what makes a vehicle more or less understeered.
eBikes now a day have involuntarily grow the CS just to fit the motor, just by concidence, 0 credits to them xD
Bikes are finally getting to MX geometry. Better in every way BUT the only gripe is that on long bikes is harder to pick up the front, wich in a moto is no problem since you do it by trhotle.
ebikes are generally longer cs for the motor fit issue you named, yes, but my main work is to make good mountain bikes: ebikes are all crap anyway
So I dont understand why my Nicolai G1 felt horrible with a 30mm stem and abolsuty perfect with a 45mm stem? I'm confused
multiple reasons, we have to investigate, if you pass by finale ligure give me a call and we work that out ( possible causes are: wrong size for your height, wrong suspension settings, short cs, etc )
Great video!
Who makes or where do you get a 15-20 mm stem these days?
at RULEZMAN . I make them
Onoff makes the kryptom direct mount 10mm stem. Tried it a while ago on a bike with a long reach but it felt like shit. Went back to short reach, very open head angle and 50mm stem.
@@padraicbateman I am 100% sure that suspension were bad set, and chainstay and wheel base was too short. According to my tests 10 mm stem works pretty well if all other aspects are in the right spot
@@RULEZMANSUSPENSION Reach and chainstays were roughly simillar (r: 445 - cs: 435). I'm quite a perfectionist so I do a lot of bracketing in different locations till I find the best compromise or rather a usable range. At the same time I was testing with the fork offset, so used the 10mm stem on a Chris Porter Morc 36 (Fox 36 lowers converted to dual crown), that allowed me to make a lot of testing over 3 months to find the best setup. Morc uses Formula dual chamber air coil, not the best but still managed to get it pretty dialed. On the rear I was using a kitsuma coil which had to revalve to my weight due to too much rebound damping from stock.
In all honesty, it didn't feel like bad everywhere. Natural trails or more rough enduro style felt pretty good but bikepark style felt terrible.
how TALL
are you , man?
What do you think about trek slash geo?
I ride long CS bikes.
Where could someone from the u
US get stems like this? I don’t see them on your website.
DM us!!!!! Ig , Fb, email, or whatzzap!
Nice discussion! I am intrigued by the short single crown stem you showed in the video. Will this be available for purchase in the future?
yes this is a prototype, the V3 will be for sale soon
@@RULEZMANSUSPENSION Great! Looking forward to it. I’ll probably get one
@@brandonb6164 before it sold out!!!
@@RULEZMANSUSPENSION Where will this become available? Should I contact you directly?
yes, next month
Sounds amazing! would you like to do a podcast video for the Israeli audience as well?
Plus, can you touch base on the logic for XC based bikes and not only DH/Enduro ones?
dm to tak about this!
@@RULEZMANSUSPENSION
How can we speak? can you leave a way to reach out?
rulezman.com you get all infos
Mondraker is playing a lot with these ideas
Brilliant!
Where can we buy the stems? Your websites seems to have 2020 and 2021 references and the price list site gives a 404
I should take down my site actually😂, just DM me on IG, FB or email!!!!
Is it possibile that a 485 R 1260 WB ( L size starling murmur ) works for a 173 rider with this stem?
seems good.
So, what is your geometry with custom stem?
I say this in the video
Traditional cantilever stem causes ackermann angle effect to the hands ?
ackerman does NOT applies to mountain bikes neither motos
@@RULEZMANSUSPENSION I was referring to the angle of the wrists at the left and right bars being different , nothing to do with the front wheel
I explained all with the drawings: arms are different.. big mess.
@@RULEZMANSUSPENSION yeah it's a great tutorial thanks. Maybe the bicycle makers will take note, we live in hope
finger cross bro…. but I believe no one will care
Hi Dave, good video. Do you intend to do a more in depth video presenting more complicated mechanics? The general idea is there and your message and assumptions seems sound but I personally would appreciate at least one level deeper - especially for thesis' like the lack of effect (or significance) of forces through the arms/hands or your statement that zero length stem does not cause bending forces to the fork. Also how do you come the right geometry figures? what is the connection to human biomechanics ( or putting it more simply - why not 600mm chain stay?) do you have a white paper that you could share of your calculations? I would certainly enjoy reading.
I have other films and videos planned, no time to go deeper even because 98% of people would be just bored by the tech. If you pass by finale ligure you are welcome to come and talk directly with myself on any topic.
where to buy your stem? hope you can ship worldwide.
sure I do. DM for info
I really like this presentation. I have a hard time with long CS unless I have a motor propelling the rear wheel and can change turn radius with throttle. On a MTB, long CS just opens up the needed turn radius for a given turn, and/or requires you to square the turn w/o throttle, or do a nose pivot to bring the rear wheel around. The grip is incredible, yes. But the maneuverability suffers for me.
each one can buy/usw what suit him the best: myself and Aston can not ride short bikes any longer and we are totally convinced the whole mtb world still has to grow in size! btw.. I rode motos for 30 years but CS on my hondas cr… was Way Longer than stupid mtb 430mm 😂😂
@@RULEZMANSUSPENSION It takes at least different skills, if not higher levels of skill, to ride a long CS bike in places with tight corners. In some situations you can set up the turn and it doesn't feel horrible to me, but I've ridden trails that force me to get off the bike when the CS is too long and my skills can't bring it around. I can imagine that if I could ride with more trials skill it would be appealing. But I still think of it like skis, you can have small R slalom skis, mid R GS skis big R SG/DH skis. At one end of the spectrum the turn almost begins itself; at the other end you must have speed to get the ski to begin a turn, or if slow you need lots of room to initiate the turn. Or a slash to start the turn.
@@seanoneil277 yeah, makes sense: the main point to me is that everyone is timing their runs downhill (enduro or dh no matter), averaging a speed of 25-30 km/h, this means to me that the speed is HIGH, and this means we need long CS / WB bikes. For sure to go at 4 ..6...8 k/h and making trials and tight trails, a bike with 26" wheels and 410 CS and 1050 WB would be 10000 times better than a bike made to keep that 30 km/h average in a easier way. My goal is to make bikes to go FAST and with less effort. I am not here to do trials.
@@RULEZMANSUSPENSION Modern UCI World Cup tracks are super high speed compared to 20 yrs ago. If I rode at that level I would want (I think, from my piker's perspective) a relatively ground-hugging suspension and geometry like what you're talking about. When I watch World Cup DH, I'm always noticing Loic Bruni's stability and smoothness and that's what I'd be aiming toward. The tight corners of a place like Schladming would take a lot of work, but I say that as a piker not a top-level rider. They probably adapt as easily as anyone could.
@seanoneil277 Loic Bruni admitted that he is old school with his bike setup he runs really short, The reason why he can ride it because his body strength can handle the bike. Compare it to Jackson Goldstone he rides very different compared to Loic he has long wheelbase and high stack by just looking at his stature, look at Assa vermette he also rides long wheelbase since he was smaller and younger.
So the only time a super short stem applies to climbing is if a bike has freakishly long chain stays?
no. it applies when chai stay is the right size for the given frame. Most of the bikes sucks. they are too short. the optimal geo still have to come.
How do I determine correct reach for my height? I'm 176cm on S3 spec enduro, 40 mm stem
about 470 x 650 true reach.
I’m not totally clear on the math here. how would I apply a/this formula to any given height to achieve real reach, which is pedal to grips?
470x650… is this an ideal reach x stack for his height?
yes it is
working on it…
Cosa ne pensi del nuovo carro specialized??
non considero cio che sta sotto ai 460mm di CS
how much for this stem in 35mm and 1 1/8" ?
sorry but 35 IS NOT SUPPORTED.
I WANT MY CLIENTS TO RIDE THE BEST ONLY, AND THE BEST IS 31.8
single crown “V3” will come soon.
@@RULEZMANSUSPENSION for you and your ideology I 'll change my 35mm bar to 31.8mm
my yellow bike feels sad now :D
why
@@RULEZMANSUSPENSION well it has all the negatives you mentioned...6 years at home already, maybe finally time for a change :)
Thanks for a great video with clear explanations!
What are your thoughts on RAD (Rider Area Distance) measurement for bike sizing?
I've seen a couple of videos where it's claimed to be a good measurement to properly size your bike (e.g. ruclips.net/video/rHagRovHSYs/видео.html, ruclips.net/video/SnXe2RmxKr/видео.html), but it seems to lean you towards slightly smaller sizes, where you recommendations seem to lean towards larger sizes.
Grazie! 🙏
RAD? stupid nonsense: RAD IS a distance without an angle and wont tell you the exact point in the space of where your bar is, while real reach and real stack ARE LIKE XY coords for your target: this is geometry bro. 1 distance without an angle tells you nothing.
@@RULEZMANSUSPENSION
Exactly. I tried saying it to Lee, but he didn't care. Than the concept of RAAD came into play which makes no actual inputs.
Even short stem can be controlled, that's exactly why old bikes with long stems disappear.
Sottotitoli in italiano 👍🏻
Are you still selling stems?
yes email us for orders
Per usare una pipa corta come la tua ci vogliono forcelle con 22mm di Offset, come si fa nelle moto da cross e enduro
NO, sulle moto l’offset è 50-60. (22 è l’offset della piastra, poi devi sommarci l’offset del piedino forcella)
Kirk Pacenti believes you. P DENT.
yes, they probably saw my stuff in 2010 and maybe copied the idea 😂 .. yeah I liked their stuff but I never arrived to BUY IT NOW LEVEL myself since I can not use my handlebars on their stems,.
I was thinking about the PDENT when I watched this video.
Non so perché fai tutto in inglese, in ogni caso davanti alla fisica le spiegazioni diventano subito inconfutabili 👍