Is Pedal Kick Back Bullshit..? | Starling Cycles Workshop Chatter
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- čas přidán 5. 06. 2024
- Is mountain bike pedal kickback a load of rubbish...?
Good question. It's a hot topic in mountain biking and we're all obsessed with the idea that our feet are getting blown off the pedals all over the place. We're especially obsessed with the idea that single-pivot bikes are THE WORST for pedal kickback.
But is it actually true..? Or is pedal kick back something we're worrying about for nothing?
In our latest vid Starling founder Joe talks about his experience of pedal kickback and a few theories on what might be (or not be) causing it, plus how to fix it.
As always, we'd love to hear you comments so please let loose in the box below!
Our references in this video:
- Pinkbike | 32 Bikes Hucked To Flat In Ultra Slo Motion (1000 FPS):
• 32 Bikes Hucked To Fla...
- Cass Labs | Does Pedal Kickback Actually Happen? I Use Data Acquisition to Find Out!
• Does Pedal Kickback Ac...
- OChain Components
www.ochain.bike
- Pinkbike | Why You Shouldn't Worry About Pedal Kickback
www.pinkbike.com/news/why-you...
- CaneCreek Hellbender 70 Visco Damper Headset
canecreek.com/product/hellben...
- RevGrips | Revolution Suspension Grips
revgrips.com
Learn more about Starling Cycles at starlingcycles.com.
And follow us on Insta at / starlingcycles .
I removed my pedals to to reduce pedal kick back
Clever man!!!
@@starlingcycles835 😂😂
I have noticed kick back while heavy braking into corners, if you accidentally lock up the rear wheel and hit a bump your forward foot will lift up. You can’t push it back down again until you’ve let off the brakes a bit. I noticed this immediately after changing to hope brakes, much more powerful than what I was used to.
I felt the same on my old single pivot bike, actually one of them was a Starling Swoop. But they would feel a bit skipperish towards a corner under heavy braking, and feel so good letting off the breaks into the corner! But i thought that was a "hold up" in the suspension kinematics, just as he showed with the growing chain. When you break you stop the chain from expanding, and you would have less travel in the rear. Any thoughts on that angle?
That's a design flaw of how the rear caliper is attached to the frame and where, they explained it to me but i suggest you look into it
@@R3ddyyg all bikes have some brake jack, once the wheel locks up placement doesn’t matter anyway.
@@MasterChronometer Well my 2014 strive user to do it very often, but on my Supreme V4 it never happened.
Idk that much about this stuff though, as I said a really knowledgeable guy explained it to me but I can't really express myself that well on the topic (English ain't my first language)
This
I've personally never noticed kickback. The only stuff I feel is the chatter and vibrations of the trail.
Exactly. It's clutch tension and the chain flapping back and forth. Any time the chain is moving like that, it's mass moving in a direction and it carries momentum, if that is moving opposite to the direction you want the suspension to move, it's going to have a big effect. These are why the bike feels so much difference without a chain.
You know, if you watch very closely, you can see in those "huck to flat" videos, at the moment they land, the chain is tight.
They are descending very vertically, after that instance, they increase forward movement.
Only some of the videos illustrate the pedals changing angles, but because the rider makes effort to brave for landing, he gets propelled forward.
I switched from lock-on grips to pure silicone grips for better vibration damping. Wolf Tooth have a wide selection of sizes and shapes. Easy and cheap mod.
Good tip, cheers! We're going to spend some time looking into all of this for a video. Cheers!
Good stuff, Joe. Thank you for these videos.
The issue is transmitting wheel forces into the chain to start with. The chain growing in the wheel path is what initiates the wave. The cause is incorrect wheel path and degradation in the drivetrain's orientation to the crank as the suspension compresses.
I did notice one thing from the pink bike video, Do kids not bend their knees anymore? When I raced MTBs in the 80's you used your legs to soak up the bumps. A little bit of "kick back" was the least of your worries.
If you're worried about kick back, ride a Full rigid Reynolds bike for a season 😂
Kids today... ( Oh crap, I've become THAT guy)
Chain slap or kickback its a drive train induced feel that many people do notice, and more on some suspension designs than others. It is likely more noticeable on a full sus vs a hard tail since due to the suspension absorbing all the noise the HT gets.
Depends on the hub engagement and the kinematics of the rear suspension. Also it's less noticable, when going faster. As you can see, the PB video shows bikes going pretty fast with a lot of kinetic energy. It's easy for the chain to start rattling. Now imagine going down a steep technical turn, with a "root or rock drop". You're going slow and draging the brakes. Finally, the rear wheel drops off and hits the ground, the rear suspension almost bottoms out, then you feel the cranks being pulled back and your knee yanked violently towards your chest, maybe even hurting your ankle. I have had instances, when My right foot gets thrown off because of that. My Iron Horse Sunday had a slight tendency for pedal kick back and when I got My 2017 Mondraker Summum, that's when I noticed it the most. OchainR helps alot, but when I case a big jump, I can still feel My knee being yanked and it can cause My right foot to come off. Downhill bike will make it more noticable, because of more travel. My YT Capra has 170mm of rear travel, but doesn't cause so much problems. Maybe the different susp. design matters. I still notice it on My Capra aswell, but only slightly. If most of you ride 140mm trail bikes, chaces are, you won't notice it, especially at speed. Once you experience it, you will acknoledge it as a nuisance.
Wicked topic. Good to see some people aren't getting caught up in the marketing 👍
I felt pedal kickback in bumps while pedaling on a low gear when i changed from a 2006 specialized enduro to a 2006 Cannondale gemini. I felt it cause I wasn't expecting it (therefore i wasn't bias), it just felt strange, but I've never felt it while descending in a high gear.
Great video!
So whats referred to as "chatter" on a GP/other race bike- it goes away when the grip level drops.
Someone interested could experiment with grippy tyres then immediately swap to a slick and see if it reduces..
Actually you can feel kickback through your feet, but it's more often just a sudden acceleration. You can clearly see it in the "huck to flat" video, the upper part of the chain is stretched, forcing the cassette to turn with the wheel, making acceleration. If you brake, you prevent the wheel and cassette to turn, so all the force is transmitted to the crank. Be aware the next time you ride a very technical section, between locking the wheel and letting it roll.
> the upper part of the chain is stretched,
But its not stretched and he said that. You can see in the videos he used that when hitting the ground the upper part of the chain between the chainring and cassette never goes taut like a string being pulled from both ends.
@@donpalmera Indeed, to transmit forces, chain needs to be pretty straight...
There’s an old saying… probably I read it in “Dirt Bike” or “Motocross Action”:
“If, one week, Roger DeCoster showed up at the starting line with a turd taped to his helmet, next week everyone would have a turd taped to his helmet.”
This is true, even on my on-road bikes, that I've put massive cassettes on, do it after acceleration in high gears 🤓
Also check Vorsprung Suspension's thoughts on this. It is on the same line as you
Nice, definitely will watch that: czcams.com/video/grNUgu0H9YA/video.html
Yes pedal kickback is a old school issue. It can't happen on a Emtb because of the sprag bearing. E=Mtb². A easy way to eliminate chain slap is to run the upper chain thru a floating length of 16mm garden irrigation pipe anchored loosely with a zip tie. As for all this high extra sprocket rhubarb... "hopefully they have Patented it to stop everyone else making the same mistake." E=Mtb²
Well also the back wheel can just turn a bit if the span between the crank and the cassette gets longer as described. But maybe some people can still feel something.
Pedal kickback is not an issue during “normal” riding - it’s like coasting downhill and then trying to pedal in a low gear, the freehub mechanism will not “catch up’ with the wheel rotational speed!
Great points. One thing you miss is there is not chain tension in real world riding be the CASSETTE MOVES AS WELL. It's not a fixed point. pedal kick back is completely overblown
Well, ride any VPP bike especially one with links that rotate in opposite direction. Santa Cruz is famous for their pedal kit back it’s science, but most people can’t understand math and science so
If the main pivot is around the bottom bracket you won't get kick back or need an idler pulley.... just look at dirtbikes
Are there bike designs with shrinking Chain stays?
Pedal kickback is only a thing if you're hard on the brakes. We all use brakes. Suspension performance also gets worse under braking because braking reduces the rollover ability of the rear wheel. (Remember 'rollover' - it is the reason bigger wheels roll better.). So riders use Ochains to prevent this deterioration from being any worse than it has to be. Even a tiny performance gain is still a performance gain. There's very few designs out there that suffer zero kickback under all/any situations.
Look, pinkbike told me that if it's not made of CF and doesn't 20 or more bearings in the linkage the kick back will be so bad the bike will basically explode jumping off of a curb. Those guys have many many more hours of watching videos of other people riding bikes, because they don't waste their time actually riding, than you or I so we should trust what they say.
Is this what would be considered a “bumbling”comment? I better ask Pinkbike!
@@jeremyprovonsil7886 No, this is a very serious comment. I'm not the type of person that rides a bike to have fun or any of that nonsense. I watch videos of other people riding bikes so I can write comments on pinkbike about how they are doing it wrong by having fun. Bikes are serious business.
The only times I've noticed it (not saying it doesn't happen in other scenarios) is on a climb. I had just cleared an obstacle, so the argument that what I was feeling was just the obstacle making it harder to pedal is not true here. Right upon clearing this 4-6" tall log or rock, the rear wheel came down off that and my full weight compressed the rear suspension as I pedaled forward. Since I was moving at a snails pace, the effect was quite pronounced of the pedals rotating backwards.
of course theres no pedal kickback when you have any speed and the wheel is rolling faster than the chain can yank on the pedals, especially since we're in the small cog when dhing. Do a drop to flat with rear brake locked and itll kick-but who does that?
Is pedal kickback is "more pronounced" if you lock the rear wheel whilst the rear suspension is active in a big cog at the back. (Wondering if the chain would go taught if the rear wheel cant rotate). (Granted, case of learning to ride properly but may be what people are feeling). (I agree though :-) )
Yet another reason why proper braking technique is important
When I've had a freehub pawlsl occationally seize you could feel it then!
Those slow motion huck to flats are kinda scary. Alot more flex than I would guess.
Chain movement is taken up derailleur and free-wheeling hub.
I've heard titanium bars reduce a lot of chatter in the hands. Would be super interested to get your opinions.
I have some titanium bars, they do feel a bit more comfortable. But as with all these things it's only small changes. More important is not to hang on too tight!!!
Pedal kickback doesn’t happen because the wheel can rotate away the chain growth. This is why you feel it the most under heavy braking. I would assume the pedal kickback would be much worse in huck to flat with the brakes locked up.
I agree. The chain growth will just drive the rear wheel. Only if the speed of the rear wheel were to drop really low, and you were causing large compressions of the rear wheel. Maybe under really heavy braking in certain circumstances..
How can you agree with someone that says "it doesn't happen" and "you feel it the most" in the same short post?
@@aucklandcycleworks Yeah fair point, I only really read the first line. Too lazy to read all of anything in detail these days. But I still agree that pedal kickback can only occur when the rotational speed of the cassette would exceed the rotational speed of the wheel. In the demonstration in the video, where the cranks rotate back, it wouldn't happen if he spun the wheel at the same time. The question comes at what upward axle velocity, in what gear and at what wheel rotational speed does the effect happen? If one might say, I feel it clattering over braking bumps, are you sure you're not just feeling the braking bumps. Or feeling the intermittent braking forces as you bounce over the bumps with your brakes on?
@@aucklandcycleworks how about I amend my statement to “pedal kickback doesn’t happen WHEN the wheel can rotate away the chain growth”?
I have personal felt it on a high pivot and it actually felt really bad ..
Wouldn’t a high engagement hub be a close runner-up for feedback through the pedals? After a hit/huck to flat/etc…pretty much anything besides freewheeling backwards will result in drive engagement feedback which will “kick” the pedals, however little that may be.
Yes. I don't go over 50 poe for this reason.
If it’s flapping chains, then it should be possible to feel it on a hardtail too. Can people feel it on hardtails?
You'd have to add a rear shock to cancel out the bumps travelling directly from the back wheel into your bum and feet trying to buck you off the bike before you could tell if it was just the lack of a rear shock or some bike woowoo causing your feet to leave the pedals.
do pinion/gates FS bikes have the same feeling of kickback? I'm guessing not
There's still a chain/belt connecting the wheel and pedals, so maybe there is
Not sure, but the weight of a belt is probably less, so effect would be reduced.
Pedal kickback is a solved problem in most modern designs but was defiantly present in older high pivot designs, eg I used to have a 98 Sintessi bazooka which would have noticeable acceleration on landing.
Oh, cool, that was my first downhill bike. I ended up selling it to an eccentric collector
unpopular opinion, pedal kickback is good, it keeps your feet parallel with the ground or the angle your body is weighting the bike through your feet constant as the rear of the bike and bottom bracket drops during the rear travel's wheel path.
"There is no mechanism for transmitting forces to your feet". I don't see enough arguments brought up in this video to back up this statement, there is no explanation really. If you had instant engagement in your freewheel and could not turn the cranks, you would block the whole rear suspension movement. That's the mechanism. Now you could argue how fast the coasting speed would need to be in relation to the tangential speed for the rear axle and gear ratio in order to catch up, but this is not mentioned in this video. Regarding chain movement I aggree, Steve from Vosprung Suspension did a great video on that. But also, besides inertia, pedal kickback could potentially contribute to the oscillations.
I have a have used stfu (these are basically rubber rings that are mounted on your chain stay that limit the motion of the chain) and haven't really noticed any improvement except noise reduction. So the problem of blowing feet from pedals (flat pedals) when hitting exposed roots hard at moderate speeds still persists. I can imagine there are types of terrain you would never have the problem.
My point is that the chain is never straight, therefore it can't transmit forces, other than those from accelerations of flapping chain. This is independent of hub behaviour so no need to consider.
Solve the dynamic system shown in the 'huck to flat', not the static system.
@@starlingcycles835 Ok, now I get it. Regarding the hub behaviour: a higher degree of engagement hub would allow more back and forth motion of the cassette during the chain flap, a lower engagement hub would ratchet away the free chain length so to speak. e13 are working on a freewheel that disengages which would allow the cassette to rotate forward as far as I understand. So it's a bit like what ochain does.
Actually, looking at this slow motion footage from Val di Sole, the chains are surprisingly straight: czcams.com/video/cRqkr-Xgg2k/video.html.
Instead of adding dead weight to DH bikes, yes that works since mass reduces resonance frequency, lighter alloys parts studyied for their damping capacity could be strategically part of the frame, titanium & aluminium alloys can be very effective; "due to their ability to dissipate energy through dislocation movement and crystallographic defects. It is possible to tailor their damping performance for specific applications by altering their microstructure and reinforcement volume fraction."
Stolen straight from tevema website 😂
But you get the point... Resonance could be tamed with existing solutions...
I think its more at a system level than material level.
What frequency range are we talking about? Sound like road/gravel bike territory. High frequency vibrations are not really interesting vor mountain bikes because high volume tires and softer compounds filter most of out even if we don't consider suspension (at high frequency we could probably assume it's rigid, but there are lot of parts like bushings and bolted joins that contribute to damping).
I don't pedal kickback is a thing going downhill - it's something I feel more going uphill. As you pedal up over a log or step up, the pedal force increases a bit and there's more resistance at that very moment as the rear susp goes into its travel as you hit it.
So you would rather recomand a stfu than a o-chain?
Would be curious to see how a high pivot bike without an idler pulley would feel.
Ah, I see what you did there. Nice.
This is a good point. Without the idler you probably would see some genuine pedal kickback effects. The idler is required to bring behaviour in line with more normal pivot positions.
Its not bullshit, but its blown out of proportions. People make such a huge deal out of it. Like if you dont compete in fkn redbull Hardline you dont need to care about that, spending huge money on hig pivot and sht.
0:56 now do the test with the wheel spinning, as it happens when you ride your bike. Surprise, no pedal kickback. Because the chain growth is not big enough to rotate the cassette so much that it engages the hub, at most riding speeds. Static analysis are so misleading... For a proper dynamic analysis watch: "What is PEDAL KICKBACK?...Should you care?" from Trail POV.
O-chain is mainly an expensive placebo, improving a non existing problem.
Hooray! Someone’s having some sensible thoughts on a ridiculous subject! As melindajones304 has said. The kick back is caused by the freewheel pulling backwards on the chain so you’ll only feel it if you’re in a big gear going REALLY slowly. Otherwise all that happens is the free hub to wheel speed difference slows by such a tiny amount it’s completely irrelevant!
As for feeling it when hitting suspension compressions during climbing that’s also ridiculous. You aren’t feeling kick back. You’re feeling the extra resistance of having to make the wheel climb up over an obstacle. Suspension is reactive to the impacts it encounters. It doesn’t lift your wheel to avoid the impact using some magical powers. You’ll feel the exact same thing on a hardtail only even worse because there’s no compliance at all.
Loving the content starling. You are a sensible thinking logical company in an industry of marketing pseudo science. Keep it up!
hahaha ok. who would've thought you'd feel feedback through your pedals when you're riding a rough trail? however the marketing department is loving this kick back to say their suspension is better so you'll but their bike. meanwhile, riders are eating that crap up and believing it. riding a bike through rough trail at speed should feel smooth!
Of course pedal kick back is an issue. The companies trying to sell you things to combat it say so.
Another bs opinion… in my opinion- suspension lock out, stiff cycling shoes, and all that body language amateurs do when paddling out of the saddle to look cool.😂