What is PEDAL KICKBACK?...Should you care?

[@oxirosmusic]

Wishing all those magazines out there like pink bike would do analysis like the ones you do. Start your own bike review website!!

[@TrailPOV]

Thought about it, but then I'd have no time to actually go ride

[@Andrew-kz9os]

That's some serious math :)

[@TrailPOV]

Yup. Hope it was made easier with the animation :)

[@frothmonster9728]

After breaking my chain at a bike park a few weeks ago and running chain less for 1/2 the day, I now pay way more attention to pedal kickback. I didn't realize how much the kickback actually effects riding when doing downhill, especially in slower more technical descents, where low speeds with big hits are the name of the game.

[@TrailPOV]

Its smooth and quiet!

[@selmtron]

I spent some time chainless, and found most pedals will back out if you aren't pedalling forward... had to tighten my pedals a couple times a day, for the 2 months I spent chainless.

[@frothmonster9728]

@@selmtron what pedals do you run? I haven’t had this issue before.

[@MS-pw8yu]

Man, that is some in depth analysis. Thanks for the hours of work you put into that.

[@TrailPOV]

Thanks for appreciating the time involved!

[@danielwu7238]

Wow this is some quality content. A lot of thought and effort went into this. Thanks for sharing your knowledge with us.

[@TrailPOV]

Glad you liked it! I hope it helps.

[@danielwu7238]

@@TrailPOV I really enjoyed it. Makes me appreciate all the engineering that goes into designing MTB bikes and suspension kinematics. Have you ever considered making a video about the difference between faux bar vs four bar suspension especially when they both use a rocker link connected to the shock? Even though both look very similar (both have 4 pivots points and are progressive suspension due to rocker link), the only major difference between the two is four bar rear axle pivots separate from chain stay, but in faux bar the rear axle pivots separate from seat stay. I wonder how that actually differs in riding like anti-squat and anti-rise and if one is better than the other. Hopefully I communicated that properly. Not sure if I put in the right words or not.

[@TrailPOV]

@@danielwu7238 Faux bar and single-pivot are the same when it comes to anti-squat and can be the same with anti-rise depending on brake mount location. The leverage ratio is where the two are different. Also don't be confused with a rocker link = progressive, as you can have a rocker link with a non-progressive response depending on how the links are layed out

[@Channel-io1di]

You changed my mind. I've been listening to reviews mention kickback and I've thought about how it works. I thought it wouldn't matter if you're moving but nobody goes into detail like you did. Very interesting.

[@TrailPOV]

Glad it helped

[@NathanRaymondBarker]

Rear hub POE should be included in determining an acceptable amount of pedal kickback as well.

[@TrailPOV]

The pedal kickback will always exist, the hub may just reduce it when there are smaller suspension movements, but it's very dependant on the pawl position at the time of the compression whether it'll reduce it any

[@themagicillusions]

Why do people always mention hub POE when talking about kickback? That might have an effect at low speed when doing big drops or something that would make the rear squat in aggressively at low speed. At high speed the rear hub has far less of an impact on kickback than something like gear selection or crank length.

[@TrailPOV]

@@themagicillusions The reason is that say for instance you have 36deg of kickback and a 5 deg engagement hub, then theoretically if the pawl is such that it takes 5 deg of wheel movement before it engages the next pawl and pulls the chain, that you could decrease your kickback by that 5 deg from 36 to 31 deg (gear dependant of course). However it should be noted that the pawl location could be that even with a 5 deg hub you dont get any slack in the system since the pawl just engaged it's next tooth....luck of the draw

[@joshuahuang07]

@@TrailPOV unless you're running those onyx clutch hubs that have instant engagement haha

[@TrailPOV]

@@joshuahuang07 Very true

[@mtbsavant5414]

Love it, best explanation I've seen!

[@TrailPOV]

Thanks very much! It was insane amount of work, but glad how it turned out 😀

[@GuillermoGonzalez-db3sx]

Killer video ! Thank you for your time and effort in creating this high quality content!

[@TrailPOV]

Thanks very much!

[@nicrepond9350]

Excellent analysis with super visuals. I’ve only ever experienced kickback on the Capra in steep, relatively slow big hit settings a- which matches your analysis of when it would be the most aggravated. I found it very noticeable and felt the suspension lock up appreciably under these conditions.

[@TrailPOV]

Thanks for the feedback!

[@Tactital]

Now i understand why specialized put low engagement hubs on the enduro

[@milktop1]

sneke Cz it’s gone with high engagement hub upgrade for me

[@TrailPOV]

They could have also done that due to cost, but possibly to minimize feedback.

[@TrailPOV]

@@milktop1 It all depends on how you enjoy your bike to feel. I don't enjoy the annoying buzz that comes from high engagement, but some people love it

[@milktop1]

Trail POV mine is almost silent. I hate loud hubs

[@Tactital]

@@milktop1 you can make high engagement hub silent by adding more grease but it didn't always work

[@amirquicklip8646]

Thank you TrailPOV!😊 I have a tricky question for you: Lets say I have a special rear hub freecoaster that, whenever Im coasting it automatically shifts the driver (pawls) out of any contact with the ratchet ring of the hub. Will this special hub eliminate pedal kickback?

[@TrailPOV]

Yes it would. If there is no interaction between wheel and cassette during coasting then no pedal kickback :)

[@nikoyannaros48]

Yes I do feel the pedal kickback on my nomad v4 while pedaling. I use flat pedals and pedal kickback can be annoying. The more alive the suspension is the more pedal kickback it has. More sag, less pedal kickback. The size of the chainring has an noticable effect to the pedal kickback. Smaller chainring, more pedal kickback. These are things that I've noticed while riding. I feel that. I'm not an engineer. Interesting to see the theory and what it means practically. I want to mention the marks on the freehub that are caused by the cassette. I believe they come from the pedal kickback in certain situations. Slow drop for example. Gear matters, too... you talked about all that stuff. Yeah, I know the feeling when a bike jumps forward with the movement of the suspension. My old votec v8 was like that, 165mm travel. Disadvantage was a massive pedalkickback while pedaling and also the suspension stiffend up while breaking. Felt almost like a hardtail while breaking.

[@PickledShark]

You know, I think you just made me a better technical uphill rider. Not only does hitting a step with your rear wheel slow you on the obvious way, it causes Pedal Kickback. I already wondered why it sometimes feels harsher than it seems it aught to. The next level realization though, is that you can also use the rear suspension to assist you over that same step, by preloading for lift, and using the kickback for boost prior to the step. Gives me some ideas to play with

[@TrailPOV]

I'd say you're probably still better off using weight shift to get you over step obstacles

[@tristandelang3324]

Best part of vid at 2:55 sweeet!

[@TrailPOV]

Haha. Was wondering if anyone would comment.

[@DanielDyla]

Great video, keep them coming! One quick nitpick about the 1.5m drop example. It seems like in your 1.5m drop, you assumed the suspension didn't slow down the rider at all. I'm sure you're aware of this, but it actually makes the speed needed to not experience pedal kickback significantly lower as it will actually take longer than 26ms for the rider to bottom out the suspension. Without the rider weight and spring force (not to mention air springs and bike geometries are non-linear) it is hard to estimate the actual time it would take from contact to bottom out. Assuming a perfectly linear suspension, a 70kg rider set up at 25% sag means the suspension's effective spring constant is about 18000 N/m, and the spring absorbs around 200J of kinetic energy before bottoming out. That same 70kg rider moving downward at 5.4m/s has about 1000J of downward kinetic energy at the point of contact. Without getting into the integration needed to actually calculate the bottom-out time, I would give a thumb-in-the-wind estimate that it would actually take more like 30-33ms for the suspension to fully bottom out, which would result in something more like 15-16 mph.

[@TrailPOV]

When the rider has dropped the 1.5m and the tires first touch the ground he is travelling at 5.4m/s. He then moves downward another 170mm and stops during this time. Using the formula Vf^2 = Vi^2 + 2*a*d where Vf = 0, Vi = 5.4m/s and d = 170mm therefore the net acceleration (including gravity) required to stop him in 170mm is a = -86.4706m/s^2. Using the formula d = Vi*t + 1/2*a*t^2 one can use the d, Vi and a value to calculate t, which is 26ms. This takes spring forces and rider weights out of the equation.

[@akjdhfkqwrhetkjanfvkkkresae]

@@TrailPOV Great job on the video! I was hoping to see this equation with the actual speeds when I watched steve from vorsprung's video about kickback. One small nitpick is that the legs of the rider actually absorb a lot of the impact about half way through the travel. This slows the time it takes for the suspension to bottom out. Take a look at pinkbike's hucks to flat to see the "pause" I am talking about from rider movement. I wouldn't expect this to be included in your video just due to the complexity! Thanks again for the valuable info!

[@TrailPOV]

@@akjdhfkqwrhetkjanfvkkkresae Thanks for the feedback

[@skandi6863]

​@@TrailPOV I think you've made a mistake somewhere. Time t should be 63ms. You can check this is correct by entering t=63ms back into your formula to confirm d=170mm.

[@TrailPOV]

@@skandi6863 I can't believe I didn't didn't catch this. Turns out I had tweaked a formula in Excel and didn't remove the negative sign so it had a negative of a negative. So the speed one needs is actually only 11.7km/hr to avoid pedal kickback on a 1.5m drop, and only 8.3km/hr on a 0.75m drop. That's totally doable!!

[@saksittichompoo3583]

Great work, again. Gonna have to watch a few more times to truly understand that and also go back and find mechanical of machinery book ;)

[@TrailPOV]

Thanks. That's the great thing about vids is that you can rewatch :)

[@jacob_wilson_236]

I love that your so informative on this stuff and thats why I subscribed thank u!

[@TrailPOV]

Thanks for subbing!

[@jacob_wilson_236]

@@TrailPOV No problem u deserve it.

[@jymtb]

Gonna have to rewatch this a few times... so much maths and science... but love it and your channel!

[@TrailPOV]

Glad you enjoy it!

[@philipgerlach2604]

can you make a video about the specialized stumpjumper?

[@milktop1]

Great video, I appreciate the work. I happen to own this bike and I can tell you firsthand it did have some pedal kick back until I upgraded the hub and now I feel nothing. It has the best grip of any bike I’ve ever ridden, super efficient and feels like a cloud.

[@TrailPOV]

Nice. Did you go with a higher or lower engagement hub?

[@milktop1]

Trail POV yes higher engagement made it buttery smooth which is maybe counter intuitive. The axle path is magic on this bike, doesn’t hang up at all.

[@TrailPOV]

@@milktop1 Very interesting. Thanks for the response

[@Veil_Ants]

I experienced pedal Kickback for the first time this morning on a slowish speed 6-7 foot drop and I can honestly say your analysis confirms that pedal Kickback is probably what I felt. I was not going fast enough to counteract the pedal Kickback and the drop was even bigger than your example. I'm not sure what the pedal Kickback on the Privateer 161 would be but I swear my pedals kicked back almost 90°.

[@TrailPOV]

Haha. New bike?

[@adamcvanwinkle]

On my old Diamondback Release I noticed a fair amount of kickback in big lower speed drops, which I did a lot of on that bike It never felt good choppy fast rough terrain, but pumped very well and felt fast on flow trails.

[@TrailPOV]

Thanks for the feedback!

[@WesMacaulay]

Phenomenal analysis that incorporates the kinematics of the rider! So during descents, if your rear wheel is rotating fast enough there’s no chance of experiencing pedal kickback. It would be interesting to make an Excel spreadsheet of the max size drop you can hit at a certain velocity and gear combination 😎 (though to be honest the emoticon should be 🤓 )

[@WesMacaulay]

As I mentioned below, bike shops should tell riders to avoid hitting big jumps in low gears 👍

[@TrailPOV]

Interesting thought. The problem would be you would need to know the chain growth, wrap angle change (you could probably average this), and chainstay growth for each bike to do something like that.

[@WesMacaulay]

@@TrailPOV Yeah, it would have to be a custom spreadsheet for your particular bike. The amount of CAD/CAM analysis that has gone into bikes in the last few years has really paid off... you can feel it in how much better bikes ride now than they did a decade ago. It's a great time to be a mountain biker! When I think back to the MTBs I sold, built and rode in the early 90s, I'm kinda frustrated since motorcycles had disk brakes and full suspension back then - why couldn't MTBs have had those, too? I guess it's just taken that long to get here, given that MTB only was 10 or 15 years old at the time, and few dreamed of turning an MTB into a full sus setup like a motocross rig.

[@nictreadgold6411]

If watch the vorsprung video on this topic you can see a real world example of the 36 degree scenario, you just drop a bike on flat ground and watch the cranks move back a very large amount, however you can simulate a more realistic scenario quite easily, take a decent amount of pressure out of your rear shock (enough so you can almost bottom it out with slightly more than bodyweight) and then ride along at moderate speed, jump up off the pedals and move you feet out of the cranks to then slam down your weight through the seat to compress the suspension, you will notice far less kickback due to the bike moving. I haven't tested this with different engagement hubs, but you could simulate the difference between a high engagement and low engagement hub. Out of interest, would the "neutral" gear that some DH racers install on their cassette completely negate kickback? They have a blank gear in the middle with no cogs so the chain can just slide back and forward.

[@TrailPOV]

While it would eliminate kickback as the wheel can no longer pull on the cranks, there will still be a tiny bit of force coming from the derailleur clutch as the chain growth still exists so the derailleur would have to extend slightly to allow this extra length...this force would be working against suspension movement though, not the pedals

[@marcowalther7867]

Super interesting. One thing I found is that trails we ride changed along with the bikes: due to the groomed trails in bikeparks getting the norm, the drops and jumps are happening with a lot more flow and speed, hence maybe less sense of kickback when riding for the majority of people? When the rooty, twisty steep trails in the woods were the norm, I had a bike with a lot of kick back and found it really unpleasant.

[@TrailPOV]

Interesting thought

[@Varaxis]

I definitely expanded my understanding on this thanks to your insight. Would love to experience a long travel bike that pedals up climbs with all these quirks minimized. Long travel Forbidden?

[@TrailPOV]

Thanks! A long travel Forbidden is basically a Commencal Supreme

[@rickgreer754]

I don't think that I've ever experienced pedal kickback while riding. If I have then its effect was, for me, in the noise considering the total trail feedback. As a practical matter, since the wheel is rotating in the direction of travel it seems like the would be minimal "like a short pedal stroke without pedaling" as was mentioned in the analysis. Great job by the way. Your explanations do help me understand the effects of suspension that I do feel such as the anti-squat. Thx.

[@TrailPOV]

Glad to hear it was helpful

[@ApexArchery]

One really interesting note is that when doing the "worst case scenario" analysis, we discussed the required forward wheel motion in a 25 tooth cog. That said, I think it's much more typical that most folks are using their smallest cog (10-11 tooth) for most descending. I am not even the strongest of riders, but even on "blue" trails, I am descending almost entirely in my smallest cog. This would have a significant impact on pedal kickback and the wheel speed required to eliminate the issue, yes? However, as the owner of the Enduro mentioned in this video, this analysis helps to explain why the bike actually feels calmer and more easy to ride on days when I am really cruising! Interestingly, on days where I am decidedly trying to ease off an take things slower, the bike itself can feel more tiresome to ride - likely due to the increased force transmitted into my feet from the slower wheel speed.

[@TrailPOV]

You are correct on this. I tend to ride in a slightly higher gear so that I always have some in the tank for a sudden uphill, but yes the smaller rear rear would greatly help kickback. The square-edge hits could also be less jarring if you are having a chill day which makes your bike feel calmer :)

[@JClark2600]

@10:20 how does the lock-out impact this? I would think it lessens the kickback.

[@TrailPOV]

With lockout the suspension wouldn't move so you'd have no kickback

[@jakobhammerer3508]

Amazing Video!!! I was wondering if you have any sugesstions for good literature to write an scientific work about the physiks of the rear suspension of mountainbikes. Thanks

[@andrextr]

Nice video! How many hours you put on these animations? eheh. Yes, exactly! Kickback is only relevant mostly during bumpy climbings (not only kickbackº is higher on climbing gears (i.e small front chainring and large rear cogs) but also, at slow speeds and when the chain is under tension the freehub/cassette does not freely rotate forward to accommodate the chain extension). On downhills, the kickback is not very important IMO. Not only the kickbackº is much lower on descent gears but also, as you said, at faster speeds the cassette rotates forward allowing the chain to freely extend. Cheers

[@TrailPOV]

Thanks. I lost count of the hours on this one....probably close to 40 hours if I count the math + animation

[@Snooker-cn3dm]

This must have taken 100+ hours to edit. Awesome explanation!

[@TrailPOV]

They average around 50 hours to edit

[@Venom1988]

Very interesting video. I just purchased a 2022 Specialized Enduro Comp with stock wheels. I believe the hub is only worth about 18 PoE? Was planning to switch them wheels to something with a Hope Pro 5 or I9. But, after watching this video, it made me think twice. That being said, my home trails have a lot of technical sections to climb and bomb down. I am now concerned that if i were to get wheels with high engagement hubs, the climbing and descending experience could feel worse potentially? Especially when there is a need to climb tight sections with roots or rocks at slow speeds. What are your thoughts?

[@TrailPOV]

Technical climbing you might actually appreciate the fast engagement and preventing the suspension from compressing as easily, downhill I enjoy some slop in my drivetrain. I'd say just run your current hub till it does then decide

[@wildnight]

Does anybody ask regarding the fork offset pros and cons between 44mm and 51mm offset ?

[@TrailPOV]

So far the question hasn't been asked, but there may be a video about this in the future

[@mattchay84]

Great video, very interesting topic.

[@TrailPOV]

Thanks!

[@dslfrk59]

Love the suspension videos. Any chance of making one for the specialized stumpjumper/turbo levo suspension?

[@TrailPOV]

Thanks for the suggestion!

[@silvataekwondo9518]

I had bad experience on my 2020 Levo, I was going really fast n smooth on fairly rough local trail, when out no where it kicked my foot off the pedal, I almost OTB... since then I’ve been looking for reason I’m on flat pedals b hate that feeling, so I was thinking it was suspension rebound maybe wrong... watching this vid, made think a bit different... with all that was said I guess also u r try to hit the rear brake it will kick you even harder... that’s a though one!!! Thanks for vid thou!

[@The.JZA.]

Great work, your videos are very interesting to watch. I had wondered about wheel speed as well but this proves it, pedal kickback will happen regardless of wheel speed. Now to do some tests and see if I can feel it.

[@TrailPOV]

Thanks, glad you like them. Regarding speed, it is possible that pedal kickback won't be present if you're going fast enough (latter part of video)

[@The.JZA.]

Trail POV Yeah but you’d have to be going pretty quick. There are too many variables to make a direct comparison with my bike. I don’t think the Stumpjumper has a very rearward wheel path due to the pivot point being located basically in line with the top of the front chainring so I’m guessing chain growth is less than the Enduro so it would suffer from less pedal kickback anyway and therefore a lower wheel speed would be required to negate pedal kickback. Great videos though. As a structural engineer I thrive on this style of technical discussion.

[@BoomslangSuss]

How do you explain that during most downhill non-pedaling sections your upper chain is slack and slapping against the chainstay? Shouldn't that be taut if it's pulling back on the crank?

[@TrailPOV]

Happy New Year and good question! The slackness can be caused by the wheel rolling forward and if the hit is large enough the inertia in the chain will cause the cassette to roll forward with the wheel in certain circumstances, or if you head downhill you're likely to change your crank arm level to further backward to accommodate the angle for a moment, causing the chain to loosen. However, as soon as the suspension compresses it'll take up any slack (if the pawls haven't already in the hub) and that's when the kickback will rear it's ugly head

[@Cg-fh5re]

Hi. Nice video. I like the video but I would see one point different: you say that moving forward means reducing the noticeable amount of kickback (pedal kickback-wheel rotation*cog ratio). I think that is only true for flat drops without speed and roll over square edges or drop with speed. But if you have to pedal and put the chain under tension it will still give you a pretty unround feel in your knees. I for instance sold my beloved Orbea Rallon 2017 because it had a slightly high pivot with high anti squat and was giving odd knee feeling on technical pedal sections. After increasing front chain ring from 32 to 34 it got significantly better but I still sold it for the reason of too high kickback. My new thunderbolt is ways better regarding that point and does not let me feel any bad feeling in the knees and is ways more active under pedaling. Despite that the Rallon was a good Enduro Bike as it was amazing on non tech uphills.

[@TrailPOV]

Thanks for the input. Yes indeed if you're pedaling a lot and picking up the chain slack then the kickback still will be noticable and tug on your pedals.

[@pennyh6720]

That was a great analysis of PK!

[@TrailPOV]

Thanks.

[@thetrailnomad]

I understand pedal kickback now. Thanks for that. I don't know whether I've experienced it though. How would this feel?

[@TrailPOV]

Nice. It would likely be that the suspension just doesn't feel as plush and is most apparent when you remove your chain.

[@thetrailnomad]

@@TrailPOV I should ride chainless just to try it out. Having an AXS I could even remove the rear derailleur... I think I'm gonna do that once. When are you gonna do the Deviate Highlander. It's my next bike (150mm link though) and I'm curious about what you think about it. It has a very similar geometry to my Megatower but should be more comfortable, being a HPP bike.

[@TrailPOV]

@@thetrailnomad AXS Nice!! Not sure when I will have time to cover the Deviate.

[@gillishommen9577]

@@TrailPOV Actually removing the chain has many more effects than only eliminating pedal kickback. For example, the influence of the clutch derailler is removed, the noise is removed, and forces of a chain jumping around up and down are also not present. In fact these factors are probably more relevant than the pedal kickback itself. I think the 'just remove the chain to eliminate PK' is actually quite misleading, as you are doing many more things than just eliminating PK.

[@Cg-fh5re]

Hi. It will give you the feel of unround pedaling when going over rough terrain. You can mount a chain ring with 4 more teeth than your current one. If it does not feel better you don't have a problem before. I did it and sold the bike afterwards for purchasing something with less antisquat and am happier now. I could even feel s positive impact of going just 2 teeth up in the front. Was more supple then over obstacles. But I am not a suspension pro and maybe it was just so easy to determine because it was a single pivot design with very short chainstaiys

[@viktorbrozek807]

man this is awesome thanks!

[@TrailPOV]

Glad you like it!

[@nathanclair3495]

Hi, great video! I really enjoy your suspension analysis videos! Would you mind sharing what program you are using to simulate the linkage and linkage motion? I'd like to be able to analyze a variety of bikes to educate my next bike purchase, and as an engineer, I really enjoy technical analysis of the designs for its own sake (don't worry, you won't see me stealing your videos). Thanks!

[@TrailPOV]

Thanks. I actually simulate the suspensions using the CAD data from the manufacturer and a simple CAD program where I draw the linkages between the pivots. The animation is done with After Effects.

[@nathanclair3495]

@@TrailPOV Thanks for your response. Is this CAD data generally available from the manufacturer, or do you have to ask for it? Looking around Pivot's website (for example) I don't find any links to download CAD files for the bike. Thanks again!

[@TrailPOV]

@@nathanclair3495 Typically use can use the 2D drawing included with the geometry data either on the web or in the product manual. The photos are close, but include the fish eye lense effect that alters the position of the axle for instance.

[@nathanclair3495]

@@TrailPOV ahh, thats smart! Thanks a lot!

[@arismunandar3391]

Great analysis, we should use smaal teeth when descend at trail, applies any fullsus bike

[@TrailPOV]

Correct....smaller cassette size reduces pedal kickback

[@klstrucker930419]

But this also increases chain slap, so make sure you upgrade your chainstay protection

[@badsilver177]

So when you are pumping, you hold the cranks in place, which means that the growing distance between bb and rear axle increases the chain tension pulling the cassette forwards. That makes high-engagement hubs like DT Swiss ratchet actually accelerate the bike a little bit :O

[@TrailPOV]

You betcha

[@kjeldschouten-lebbing6260]

It would be interesting to see the correlation between paddle kickback and emtb motor torque sensing... At least it would up the average speed uphill, so it would help with kickback on uphill technical trails...

[@TrailPOV]

Interesting thought. IMO if the rider holds the pedal in position while the suspension compresses, causing an increase in force being applied to the pedal by the rider to counteract the chain force, the motor is likely to give a punch of power due to this surge in torque which should theoretically help in technical trails :)

[@therealridedmc]

I borrowed my friends eBike and felt this punch in power on low speed drops and in some bermed corners. It was disconcerting, but I suspect once get accustomed to it, it could be advantageous.

[@shaywright8105]

You should do the giant suspension

[@TrailPOV]

It's coming up next

[@demand37]

Thanks for the video but i still have two questions, First i want to buy the 2021 Propain Hugene and looking at it it is very similar two the Pivot Trail 429 (?).The Pivot is a Virtual Pivot Point bike and as far as I know should have very small Pedal kickback because of the extra hinge. Did I understand that right? And second is the Propain Hugene even a VPP bike because if i search it up,one website says the bike has a VPP suspension design and one says it looks like one. On the official Propain site there is nothing mentioned about the VPP only about the links.

[@TrailPOV]

Hi. Unfortunately haven't looked at the Pivot trail, but have done an analysis on the Hugene over on patreon.com/trailpov if you're interested. As to whether it's a VPP bike, yes, the rear swingarm is completely decoupled from the frame by two independent links. VPP is a trademark of Santa Cruz, hence why Propain doesn't use that exact name on their website.

[@demand37]

@@TrailPOV thanks for the answer i appreciate it

[@BMfins]

Do a review on popular rear suspension designs with positive and negative features. And what type of rider would benefit from said designs.

[@TrailPOV]

I've tried to cover bikes separately so it doesn't get overwhelming with info

[@nya1825]

What if link pivot is located at Same position with bottom bracket? Does that remove pedal kickback?

[@TrailPOV]

Yes it will since the distance between the cassette and the chainring will remain the same

[@altrevi8143]

So by using the smallest rear sprocket during downhill, the wrap angle would actually partly compensate the chain stretch?

[@TrailPOV]

Correct

[@ActvNva]

Doesn't kickback get worse in your climbing gears? Why would you be descending in the top of your cassette? I went to the garage and cycled my trance through it's travel in both ends of the cassette. In the top I can get the bike to backpedal a little. In the bottom of the cassette I couldn't get the pedals to move any noticeable amount. I am running a DT350 with the 54T upgrade. The reason I am wondering is I am building a new bike and am about to pull the trigger on a set of i9 wheels with the hydra hubs.

[@TrailPOV]

Yes definately worse in climbing gears...it's about 2 to 2.5x worse in a 50t rather than 25t. If you're cruising fast the fast engagement hubs shouldn't be a problem.

[@tomclarkson6078]

Fantastic video and I understand this so much more now. What software do you use for the computer voice over?

[@TrailPOV]

Glad to hear. I use After Effects for the video and Audition for the voice processing.

[@MrDjindian]

I didn't think pedal kickback was a thing, until the day I broke my chain riding my local trail. It was all down hill from where it happened so I rode down with the chain off and my bike felt like a cloud! Now I am anxious to find a way to achieve that feel... I might try that new chainring that is supposed to eliminate pedal kickback!

[@TrailPOV]

Canyon tried a super complex way to disengage the hub a few years ago and there are a companies doing a smooth cassette wheel so the chain can spin, but so far it doesn't seem to be common to have anti pedal kickback devices. Not sure why.

[@MrDjindian]

Maybe I'll have to get a Forbidden!

[@TrailPOV]

@@MrDjindian Good choice 👍 (PS I'm not sponsored by them in any way)

[@WesMacaulay]

I think we are going to see more high single pivot designs thanks to Forbidden - though some might find HSP designs a bit “dead” feeling. BCPOV and Pinkbike’s review of the Druid has made the bike less compelling a purchase even though the design is innovative.

[@WesMacaulay]

If anything this is a great PSA to all aggressive riders to send it in your higher gears to avoid breaking your chain :)

[@xXxCenkaxXx]

How about jamis hardline/portal 3vo suspension? It looks pretty nice

[@TrailPOV]

Thanks for the suggestion!

[@tylergentry8079]

Hey man, great analysis as usual! I actually wanted to do this exact thing but never got around to it. Factoring in speed and hub speed is important in calculating pedal kickback. Quick follow on question, what software do you use for you animation? I've never seen anything that good for depicting bike suspension movement!

[@TrailPOV]

Thanks very much. I use Adobe After Effects for all animation. This video took me well over 30 hrs to produce

[@ryanmacdonald1370]

Hey there, How does the amount of suspension generally impact the amount of pedal kickback? Would a high engagement hub for example make pedal kickback on a long travel enduro bike be more/less noticeable than on a 100mm XC bike? Is there a way for one to calculate the contents of the video at home without buying software? Is there a way to get a rough idea of how much pedal kick a bike has in a scenario where a brand doesn’t publish the information online or in a manual? Thanks

[@TrailPOV]

Hi. Generally more travel = more kickback and a high engagement hub would only make it worse since you lose out on the first couple of degrees of slack. You could calculate the content at home but it'd take a bunch of equations entered in Excel.

[@shrimpfriedrice494]

Do you have any plans to do one of these on the Devinci Spartan 29?

[@TrailPOV]

Possibly, if there's enough interest from the community

[@etibo6]

For the same bike, can you tell what will be the impact of the chainring changing size? I heard somewhere that it will be less kick back if the chainring is bigger but it make no sense to me.

[@dylancontris8697]

He explains it in the video. It's the ratio of front to rear cog sizes that will determine the kickback. Having a smaller cog in rear and larger in front reduces kickback, whereas larger in rear and smaller in front causes more kickback

[@TrailPOV]

@@dylancontris8697 You got it

[@TrailPOV]

See Dylans explanation. As for a more detailed explanation of just chainring size, as you increase the chainring size in the front, the diameter and thus circumference increases. This means for the same chain pull backward in mm, a bigger chainring will need to rotate less for the outermost point where the chain connects to also rotate the same mm

[@etibo6]

@@TrailPOV Thank you I get it now!

[@etibo6]

@@dylancontris8697 I still have a interrogation. If I put the chain on the smallest rear cog the anti squat supposed to be higher on my bike because it move the chain line intersection with the IC line backward. So I reduce the chain path but I get more anti squat. Does the impact of the increase of anti squat will be less important than the reduction of the chain path?

[@laszloraffai8755]

That is exactly, I looked for! Professional, perfect job!

[@TrailPOV]

Thanks very much!

[@wolkuz]

I noticed loud sound when I drop the rear of the bike, its clearly my free hub engages, DT swiss 350 ratchet 24T. 180mm travel coil shock. Im notice it when riding as well, any solution? Thinking to add more grease to the freehub body...

[@TrailPOV]

Grease might just make the pawls stick and no engage at all. Not sure what to suggest other than removing your chain :P

[@wolkuz]

@@TrailPOV it makes the sound only when bike is stationary and I drop it down, no sounds when riding. Not a big problem but just sucks when you cant to check for loose parts in general when dropping the bike :D

[@masondekeyrel6539]

If you add an idler pulley/wheel to the 2020 specialized enduro where would be the best location to put it? Would it help reduce pedal kickback? I have a 2020 Enduro and am thinking of trying to make one that mounts off the bash/chain guide mounts. Good idea or bad idea? Would be curious to hear your thoughts. Awesome videos.

[@TrailPOV]

Thanks. A very interesting thought of which I don't have an immediate answer for. If I come up with a conclusion whether you could actually make it help you I'll let you know.

[@Angad1826]

Does switch infinity actually reduce pedal kick back on yeti sb165? Do you have any info on that? Thanks.

[@TrailPOV]

Not sure if it was intended to combat pedal kickback. Due to the high anti-squat it does have a higher than normal kickback in the first 75% of the travel before the AS starts dropping quickly leading to the pedal kickback leveling off deep in the travel.

[@reapering125]

wait im confused according to the math when descending, being in certain gears effects your suspension feel due to the tension on the chain?

[@TrailPOV]

Correct. Has to do with wrap angle. The larger the rear gear the more the wrap angle and the more then kickback.....descending in your smallest gear in the rear helps reduce the kickback

[@reapering125]

@@TrailPOV good info

[@mphmtb]

I see the pedal kickback as a main force preventing wasting energy on climbs. But too much and the suspension will not get out of the way for the hit. I figure this is why the likes of Santa Cruz and ibis etc, want to use two linkages. To try and get chaingrowth at the start of the travel, but then minimise it towards the end? This is what I have taken from watching many of your videos. I hope I have understood correctly. 👍

[@TrailPOV]

Yup, this is how some have dealt with it 👍

[@nathanwforrest]

Is it conceivable that a set of conditions exists (suspension configuration, drop size, forward velocity, rider weight, etc.) where it would become very likely that a chain breaks due to kickback forces?

[@TrailPOV]

Definately. A slow large drop where you hold your pedals level -- if the wheel can't get going fast enough the force will be directed through the chain.

[@JClark2600]

For the last question does it matter or do you feel it. I for one don't huck to flat doing mach 5 so my ass moves down but I push the bike forward to get a lower COG. When that happens I don't notice 10 degrees of pedal kickback because my legs are a fixed length and if I move down and back my stance moves accordingly.

[@TrailPOV]

Hopefully you don't loop out as a result of having all your weight over the back wheel

[@newlife-su7sd]

i dont understand 1;04 why does wheel rotate backward?

[@TrailPOV]

It's the frame of reference. Relative to the ground the wheel doesn't move backward, but relative to the bike it appears to be.

[@Rose_Butterfly98]

So that's why my bike has the pedals rotate backwards if I stop and get off right after landing. It's weird , makes the chain come off the big chainring towards the smaller one.

[@TrailPOV]

The pedal should only rotate as you're landing and compression the suspension, not after you stop

[@Rose_Butterfly98]

@@TrailPOV like I land and get off instantly, because I basically like to jump this hump and land right in front of where I stop. Also may have had to do with the derailleur, it was apparently faulty and broke after about a year. Only had it happen once after I changed the derailleur

[@mkim64]

These numbers are great. Say you're hucking to flat again - would the suspension behave differently if during the jump: (1) you let your wheels spin; (2) you lock up your wheels; (3) you continue pedalling sam blenksinsop style?

[@TrailPOV]

In all cases the bike is moving forward still, so (1) and (3) no real difference but (2) might cause some wheel skid to accelerate the wheel up to speed of the rider which would decrease the riders overall speed slightly.

[@DylanDavidVindasLopez]

how do you make these bike analysis? wich software do you use?

[@TrailPOV]

The calculations are done by hand using a CAD diagram from the mfg and a simple CAD program in which I manually draw the lines and pivot them. The animation is done with After Effects.

[@DylanDavidVindasLopez]

can you do a tutorial on that someday, so that if someone wants to analize his own bike it can do it?

[@TrailPOV]

@@DylanDavidVindasLopez And put myself out of a job, haha 😆

[@DylanDavidVindasLopez]

Nah, your videos are extremely interesting, and your explainations are actually really good, but there are some bikes like my Huffy, that you will never analyse (not wort it i think)

[@TrailPOV]

@@DylanDavidVindasLopez Fair point. Perhaps I will put something together in the future.

[@SHREDD-ED]

Why does wheel rotation decrease PK? The chain is still pulling isn't it?

[@TrailPOV]

Head to the last part of my video for an explanation of this

[@SHREDD-ED]

I guess my confusion stems from the fact that wrap angle of the cassette should not (in my mind) be affected by forward rotation of the wheel as the cassette is "free" and the effect the increasing wrap angle of the cassette over the chain ring should (in my mind) be independent of it. Please correct me if I'm wrong.

[@TrailPOV]

@@SHREDD-ED There is only an increase in wrap if one considers a point at the top of cassette to still be at the top once the suspension is compressed. However if the wheel is rotating then a point at the top of the cassette rotates forward as the suspension compresses and that extra wrap length is covered by chain that was already wrapped around the cassette at 0 travel.

[@michi4290]

Is it possible that my bike has 0% pedal kickback or does every bike has it because when i let the air out of the shock and pump it through its travel the cranks dont move (cube stereo 140)

[@TrailPOV]

I haven't heard of a bike that has 0% kickback. With your bike, it's probably you don't notice the cranks moving because your wheel can rotate. If you hold your rear wheel stationary with reference to the ground and push the suspension down you will see the cranks move.

[@justing6614]

So the specialized enduro could really benefit from the Ochain then ?

[@TrailPOV]

From what I've heard a lot of bikes would benefit from an o-chain. Never ridden one myself.

[@Cakeborb]

Can you make a video on Jamis's 3VO suspension?

[@TrailPOV]

Thanks for the suggestion.

[@frankhutton6747]

Excellent analysis, seems like pedal kickback won't really have a big impact on a riding experience. I never realized that you could pump a full suspension bike on the flat

[@TrailPOV]

Thanks

[@premiumboard21]

Hey, can you review any trail bikes from polygon?

[@TrailPOV]

It is certainly on my radar. Thanks for the input.

[@premiumboard21]

@@TrailPOV quick question, what do you thought about main pivot attached to bottom bracket?

[@TrailPOV]

@@premiumboard21 Sorry for the delayed reply. Unfortunately I don't really have a strong opinion either way on them until I analyze one.

[@Tactital]

What about specialized demo ? Is it the same ?

[@TrailPOV]

Unfortunately I haven't looked at the demo so wouldn't be able to comment. It's possible that they made a more rearward axle path to keep momentum that would increase pedal kickback, but it's also possible they tried to reduce pedal kickback to allow the suspension to easily move. I will have to do the math at some point.

[@klstrucker930419]

Axle paths for current enduro, demo and kenevo can be found on pinkbike

[@Tactital]

@@klstrucker930419 Can you please send link ? I can't find it. Thanks

[@klstrucker930419]

@@Tactital m.pinkbike.com/news/first-ride-the-2020-specialized-enduro-is-bigger-and-burlier-than-ever.html here's for the enduro. I've also seen somwhere comparison of 3 axle paths, for enduro, demo 29 and new kenevo

[@Tactital]

@@klstrucker930419 thank you

[@klstrucker930419]

Interesting... I know there are some scientific thesis on pedal kickback and so called threshold speed on research gate, but i didn't manage to get access to it. Looks like if you're an amateur, riding slower and with faster damping setup(softer), using more travel you are more affected. That would mean bikes like commencal supreme dh 29 make sense not only for guys like Amaury Pierron. Finally i've found an excuse to buy one 😀

[@TrailPOV]

Haha. Awesome logic in needing a new bike :)

[@erpol9258]

Can you do a review of the new GT Force ?

[@TrailPOV]

Thanks for the suggestion

[@LuisGonzalez-xt2sd]

Thank you for the explanation. So, there are so many videos of pro's going up stairs in their bikes, it gets harder because that's when you will experience more pedal kickback?...

[@TrailPOV]

You're welcome. Anytime the suspension is compressing there will be pedal kickback that works against your pedal stroke.

[@Tactital]

Actualy i now realize that this maybe is the reason why enduro climbe that well. In the beginning of the video you say that enduro have the biggest pedal kickback and a lot of reviews say that enduro is very good climber . If you don't understand, when you pedalling to the hill the suspension should be less active because the chain can't go backwards when you are pedallin forward. That can allso cause some kind of energy lost because you need to give extra energy to keep the suspension inactive but that is probably less then pumping the shock all the time . Worth mentioning in the video.

[@TrailPOV]

An interesting thought....kinda like a lockout, without needing a lockout.

[@justinwbohner]

I think I experience this on my Mach 6 when climbing. I have it built as a long travel trail bike and it tech climbs amazingly well as long as you're putting down a lot of power. I feel some kickback but just push through it, and I feel the effect of being propelled forward. The high antisquat and kickback keeps the bb high, perfect for getting across rocks.

[@Phlizz]

Just for understanding: is anti squat pedal kickback on purpose to firm up the suspension when pedaling???

[@TrailPOV]

Anti-squat is the person pulling the wheel and extending the suspension slightly to prevent it from bobbing due to rider weight transfer while pedal kickback is the pulling of the crank by the wheel as a result of the suspension compressing....so very related but kinda opposite. In theory if a design could have high anti-squat and no pedal kickback that would be ideal...so it's not like they're using the pedal kickback as part of an anti-squat design specifically, it just kinda comes with the package due to physics.

[@Phlizz]

Trail POV could their be a design with a pulley wheel moving according to real axle path, with high anti squat/ prone to kickback around sag and then less into the travel? It’s hard to get my head around it... chain length should be consisted though.

[@TrailPOV]

@@Phlizz I think I understand what you're trying to say. Use the kickback to your advantage at sag to prevent bob, but then eliminate it afterward to make the suspension plusher. I can't think of a bike right now that does this particularly well, but there are designs that have this idea in mind. The problem that does arise is if you have higher pedal kickback in the first half of the stroke, you need to pull the wheel very far forward in the second half to make up for it....causing the wheel to move forward which isn't great for square-edge hit absorption. There is that tradeoff.

[@Phlizz]

Trail POV I thought about having a rearward axle path, but a idler pulley rotating around the main pivot. In sag the pulley is located to make for good anti squat, then deeper in the travel it moves to a position where almost non of the three factors affects the suspension. Is this even possible? Having a non fixed idler pulley that moves the angle in which the chain points from rear wheel to cranks for different positions in the stroke?? 😃

[@denv5023]

Anti squat is achieved via pedal kickback, so you cannot have high anti-squat with no pedal kickback. Both are always proportional. At least for bikes with rear suspension that uses a chain to drive the rear wheel. A hardtail has infinite anti-squat and zero pedal kickback. If you remove the chain and install a front hub motor, you get zero pedal kickback, but also zero anti-squat.

[@fontafox]

Loving this nerdy madness !!! yeah !

[@TrailPOV]

🤘

[@robhaskins3068]

All very interesting but tell me if I'm wrong but a Emtb can't get kickback because of the sprag bearing. Another reason why E=Mtb²

[@TrailPOV]

Haha. Nice formula. Never really thought about it till now but yes the decoupling of the cranks to the chainring would result in no kickback

[@moosicman101]

I believe it would make sense if it decoupled going backwards. But since it only decouples going forward, then it is the same as any other bike.

[@thelongestnameinthecomment9677]

Some downhill bikes would be awesome! Keep up the good work

[@TrailPOV]

Noted. Thanks!

[@barrakingbeatz7794]

The Scott ransom has some good amount of kickback

[@TrailPOV]

Thanks for the input

[@mt2nv1]

Recently read an interesting article from DT Swiss in the negative effects of increasing hub points of engagement on pedal kickback. It would be awesome if you could explain this inverse relationship! Thoughts?

[@TrailPOV]

A high engagement hub means that the first few degrees of slack in the hub are eliminated meaning every small movement of the wheel would result in pedals moving, rather that the back wheel needing to move a substantial amount before the hub pawl engaged. A high engagement hub would most significantly affect the small bump sensitivity as a result.

[@mt2nv1]

@@TrailPOV thanks! Possible video idea? I’d love to see a video comparing different engagement hubs and at what wheel speed is this void due to the hub body moving faster than the free hub.

[@jurgentrockenbau9321]

Yes, a video about poe and pedal kickback would be awesome!🙂👌🏻

[@GiordanoDeVecchi]

How could a device like o-chain, that reduces kick back, affect the reasoning?

[@TrailPOV]

Rather than the chain pulling the cranks backward, it would pull the ochain backward so the rider wouldn't feel the forces of the kickback in his pedals....seems like a good idea. It's unfortunate that the website doesn't give details about their mechanism for rengagement of the pedals.

[@thiebaultguillaume2526]

Hi Matt, as you let us understand you are havingna lot of demand for producing bike analysis, i am proposing myself to help you. I know how to use linkage and do analysis, let's discuss what i can do for your channel

[@TrailPOV]

Hi Thiebault, thanks very much for the offer. The video animation of the analysis takes waaaay longer than the analysis hence the delay between videos. So far I can handle the analysis. But will keep you in mind if things change.

[@strongme80]

Just watched the video, I now need a drink!

[@TrailPOV]

Haha

[@hunterwright386]

never heard of it until i experienced brake jack and pedal kickback at the same time. i was like"where did the bike go?"

[@TrailPOV]

Hehe

[@PhiLoSoPheR_NonSenSe]

I believe providing a ratcheting mechanism (like in a freewheel) to the front chainring will reduce that kickback... consider this...

[@TrailPOV]

Yup. This is what the Ochain is trying to achieve and apparently does a really amazing job for those who use it.

[@PhiLoSoPheR_NonSenSe]

​@@TrailPOV Didn't know I got a reply! Greetings from Ghana. 😅 I discovered that product not long after finding out pedal kickback. Also discovered idlers in certain bikes' drivetrain.

[@TrailPOV]

@@PhiLoSoPheR_NonSenSe Happy New Year!

[@PhiLoSoPheR_NonSenSe]

@@TrailPOV Many happy returns! Looking forward to more deep dives into MTB suspension systems! 😁

[@chrish8871]

Nope not really, some wallow seems to stiffen the pedal but if the suspension is set right however I do worry kick back can accelerate an over the bars casing face plant scenario. Generally on a downhill where it matters no not at all

[@CharlieH_design]

Wow!

[@ridesafealways4929]

The old gt fury 2014-2018 suspension design almost avoided this issue entirely.

[@TrailPOV]

But it had other issues such as a seatpost to BB changing location

[@ridesafealways4929]

@@TrailPOV it's not very noticeable. Bb moves backward 1cm at most. I

[@x250f23x]

I was watching for kickback in this vid ( kzbin.info/www/bejne/jGK7inaMf9lmjKc - huck to flat) especially the enduro at 1:30 with its high angled number. Even at the moment of touch down and then thru out the travel range, the chain is slack and bounces around. 🤷🏻‍♂️

[@TrailPOV]

Really good observation. The two things to notice with that test is that the wheels were moving (unsure exactly how fast), and also that they were in a really small rear gear (say an 14 or 16) which reduces the kickback significantly. Even in my experiment going from a 50 tooth to a 25 tooth reduced the overall kickback from 36deg to 24deg. But definitely worth bringing up, as real life can teach us a ton about how best to analyze.

[@ej1_drew]

pedal kickback blows out my left (front) ankle when i land a little too hard :/

[@TrailPOV]

That doesn't sound like fun :(

[@jeromewestwood5453]

Are we getting brain washed for enduro bike to have high engagement hubs. Wouldn’t a low engagement hub be better on a bike with pedal kick back?

[@TrailPOV]

High engagement hubs are great for efficient pedaling, but yes it is very true it might not be particularly good for high pedal kickback bikes or those with large travel