Anyone use Anti-Pedal Kickback Tech on EMTB?
- Thread starter slickrock
- Start date
Yeah, that’s not good. If it is an internal motor issue @Bearing Man may have a suggestion. It might include dropping the motor.The noise I'm hearing is exactly this one :
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The noise I'm hearing is exactly this one :
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Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.
The noise in this video is caused by "backlash" through the transfer gears. It's caused by a very small amount of play between each gear tooth and magnified through several gears. The Gen 4 is like this from new, but as you can see in the video, the Gen 5 has been improved. If you own the Gen 4, there is currently no fix for this.
Indeed, this is a problem that all Gen4 C engines have. Reading previous forum pages, the E13 Sidekick seems to be effective at reducing knocking/rattle .
However, the Ochain seems less effective? I'd like to find a system to at least reduce the noise.
The nano second of motor and gear engagement has been fairly smooth for me. No clunking and steady cadence. Perhaps this is why my Bosch CX Gen4 has lasted many kilometres and almost 6 years. Recently rebuilt once in that time (prematurely perhaps) when I heard a strange noise. Turned out to be a loose castle nut. Oh well.
A regular bearing seal kit and new castle nut probably helps also.
I rarely go into turbo mode because that is too sensitive for climbing …plus it can wear out drive train components faster. EMTB mode is all I need but sometimes peddle strikes are unavoidable.
2WHLFUN
Well-known member
Bumping because no feedback. Do any of these devices stop the Bosch SX rattle?
Hello,
I have the same question as you with my bosch CX gen4
On YouTube, there's a video by Sam who says that the O-Chain doesn't eliminate the rattling.
On the Canyon Strive Facebook page, there are two comparison videos about the O-Chain (with and without).
Bontee
Active member
I don’t own anti kick on my bike but I have ridden a couple and in my very limited exposure to them it seems to be a case of a component looking to solve a non existent problem.
Just not worth my time and money ( but that’s only my opinion)
Just not worth my time and money ( but that’s only my opinion)
mhueschen
New Member
I recently purchased an Avinox bike (Forbidden eDruid) and wanted to share that I contacted OChain about an Avinox spider:
and received this reply:
I find this interesting and it seems self defeating, imo, if SRAM is trying to use this as a "wedge" against DJI in the eeb-wars.
worth noting also that Rimpact lists DJI on their eMTB chain damper, however *none* of the choices (motor + chainring) seem to show any availability on that page. weird.
and received this reply:
I find this interesting and it seems self defeating, imo, if SRAM is trying to use this as a "wedge" against DJI in the eeb-wars.
worth noting also that Rimpact lists DJI on their eMTB chain damper, however *none* of the choices (motor + chainring) seem to show any availability on that page. weird.
John_likes_bikes
Well-known member
It's right there on the RImpact page:
"Register your interest in an E-bike compatible Chain Damper so we know how many and which types to produce when we launch them soon! We'll send you a notification when they are in stock so you don't miss out."
"Register your interest in an E-bike compatible Chain Damper so we know how many and which types to produce when we launch them soon! We'll send you a notification when they are in stock so you don't miss out."
I also wonder if its strategic.
No reason not to have one if their goal is to sell more ochain devices.
Could always use DT 240 or 350 hubs' DF Technology.
I'm more weirded out by you experiencing PK on a bike with HP idler. I mean, what's the point if that weight/ maintenance/ cost doesn't solve that issue and now you have to add more weight/ maintenance/ cost by purchasing an O-chain or the like.
Are you certain that you are not just hitting a wall of progression or midstroke harshness?
Why don't you remove the rear shock (or just the air or metal spring) and push the bike through the travel so that we can observe how much this suspension design actually rotates your cranks backwards?
Also, what rear hub are you on?
John_likes_bikes
Well-known member
Likely an intellectual property buy to integrate into their line and not wanting to R&D something that's going away. I'm sure they bought it for nothing.
I've just put one of those on my trek fuel exe, I've set it to the middle setting - 10 degrees I think.Could always use DT 240 or 350 hubs' DF Technology.
Seems OK, not a night and day difference in smoothness, but it does feel a bit smoother.
mrtrinh
Active member
I'm in the same boat, I'm also surprised he's getting pedal kickback on the forbidden. I have the druid v2 and I don't experience pedal kickback. Even on the vpp crestline there wasn't too much kickback when I didn't have my sidekick hub.
slickrock
Well-known member
- Thread starter
- #107
It's lame that Ochain does not yet support Avinox, with SRAM apparently in now hurry to anything about it. And like the members comments, It's a bit a of a surprise you are having kickback challenges with a mid-HP suspension. This could mean that perhaps you are sensitive to chain whipping effects. I would suggest looking at your derailleur, possible the clutch mechanism is a bit a loose or the chain is not sized correctly. Otherwise, in the meantime, you could add a cheap $39 STFU to your setup and see if this quels your issue.
Really bikes with the idler chainring don't typically experience any chain whip feeling because the idler stabilizes the chain, at least the part that you might feel at the feet.
What I suspect is occurring is that there are a lot of comments about how the E-core's suspension requires some unique set up decisions regarding sag and so forth. For example, when my Relay showed up it had a medium volume air shock and it was full of volume spacers combined with a high leverage ratio suspension design and basically the wall of suspension progression felt like hitting a rubber puck at about 130mm of travel used (out of 170). It sucked and set up matters.
Of course, the E-core is a mid-pivot so might still have some minor PK, and maybe he's got an Onyx hub that transfers 100% of that every time?
I would say that in this case it would have made more sense to buy a non-HP Bosch bike, save the weight/ drag/ maintenance and just install an O'Chain (hence the Bosch) or an E13 hub (works with any motor).
The way the rear suspension is described in reviews on the Rogue, that's how a HP should feel.
I'm pleased to read rider reports that the Wild I have on order is incredibly plush off the top when a coil shock is added. That's not surprising given the 40% progression level.
What I suspect is occurring is that there are a lot of comments about how the E-core's suspension requires some unique set up decisions regarding sag and so forth. For example, when my Relay showed up it had a medium volume air shock and it was full of volume spacers combined with a high leverage ratio suspension design and basically the wall of suspension progression felt like hitting a rubber puck at about 130mm of travel used (out of 170). It sucked and set up matters.
Of course, the E-core is a mid-pivot so might still have some minor PK, and maybe he's got an Onyx hub that transfers 100% of that every time?
I would say that in this case it would have made more sense to buy a non-HP Bosch bike, save the weight/ drag/ maintenance and just install an O'Chain (hence the Bosch) or an E13 hub (works with any motor).
The way the rear suspension is described in reviews on the Rogue, that's how a HP should feel.
I'm pleased to read rider reports that the Wild I have on order is incredibly plush off the top when a coil shock is added. That's not surprising given the 40% progression level.
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Blownoutrides
Active member
The emtb youtuber Sam likes bikes tested the ochain on a gen 4 cx motor (I think?) and it didn't do anything for the rattle. Guessing it would be a sim result for the SX(?).
mhueschen
New Member
I also have been surprised to experience what seems to be pedal kickback on the eDruid. I previously had a V1 Dreadnought and a V2 Druid, which did not seem to have any kickback.
I will do more extensive testing soon when I have the bike back together (currently upgrading a bunch of components). I noticed the kickback with a DT Swiss 240 DEG hub (90t).
the pedal kickback chart (attached) published by Forbidden shows quite a bit of kickback for the big cogs, though it doesn't draw all of the "lines" for each cog size. I was in the middle of the cassette (perhaps around 24t) when I experienced the kickback. it seems plausible that that cog might sit in the middle of the triangle on the chart. since the DEG hub is 4 degree engagement (averaging 2 degrees)
I both felt the kick in my feet, and could hear the sound of the DEG ratchet engaging and "clanging". I feel pretty confident in my interpretation of that noise, though, I could somehow be mistaken.
I also noticed that driving the bike home from trails another day, in the 6th cog (24t), the bike bouncing up and down on the rack on paved normal roads caused over a full rotation of the cranks in just a few miles (seen on Tesla rearview cam). this surprised me a lot, coming from the Druid and Dreadnought which I've driven on literal thousand mile roadtrips with zero rotation of the cranks. I know that the motor+battery mass causes much more bounce in the eDruid, but I still believe it must exhibit more kickback and anti-squat than the analog Forbiddens. my current theory is that this is an intentional choice of more anti-squat to manage the torque-y Avinox motor. I also find it a disappointing if an idler bike also requires a chainring or hub PK solution.
I have a custom tuned Vorsprung Telum on the bike, which is set up as Vorsprung suggested based on my weight & preferences. it's possible it is still not ideal in terms of setup, and could be exhibiting the issues mentioned above. but I suppose I trust Vorsprung's setup, and they told me they had set up this shock for other eDruids.
cycling the bike w/o the shock in is a good idea and I'll try to do that when it has wheels back on.
I will do more extensive testing soon when I have the bike back together (currently upgrading a bunch of components). I noticed the kickback with a DT Swiss 240 DEG hub (90t).
the pedal kickback chart (attached) published by Forbidden shows quite a bit of kickback for the big cogs, though it doesn't draw all of the "lines" for each cog size. I was in the middle of the cassette (perhaps around 24t) when I experienced the kickback. it seems plausible that that cog might sit in the middle of the triangle on the chart. since the DEG hub is 4 degree engagement (averaging 2 degrees)
(34/24) * 2 = 2.8 degrees average, or (34/24) * 4 = 5.7 degrees maximum of kickback at the hub is all I'd need to notice something in my pedals.I both felt the kick in my feet, and could hear the sound of the DEG ratchet engaging and "clanging". I feel pretty confident in my interpretation of that noise, though, I could somehow be mistaken.
I also noticed that driving the bike home from trails another day, in the 6th cog (24t), the bike bouncing up and down on the rack on paved normal roads caused over a full rotation of the cranks in just a few miles (seen on Tesla rearview cam). this surprised me a lot, coming from the Druid and Dreadnought which I've driven on literal thousand mile roadtrips with zero rotation of the cranks. I know that the motor+battery mass causes much more bounce in the eDruid, but I still believe it must exhibit more kickback and anti-squat than the analog Forbiddens. my current theory is that this is an intentional choice of more anti-squat to manage the torque-y Avinox motor. I also find it a disappointing if an idler bike also requires a chainring or hub PK solution.
I have a custom tuned Vorsprung Telum on the bike, which is set up as Vorsprung suggested based on my weight & preferences. it's possible it is still not ideal in terms of setup, and could be exhibiting the issues mentioned above. but I suppose I trust Vorsprung's setup, and they told me they had set up this shock for other eDruids.
cycling the bike w/o the shock in is a good idea and I'll try to do that when it has wheels back on.
mhueschen
New Member
interestingly, it seems like the Velduro Rogue might exhibit similar levels of pedal kickback. this chart shows 34(chainring)/24(cog), the same pairing I was experiencing PK w/ on the eDruid. presumably it gets worse for bigger cogs.
my theory is that high-torque eMTBs just *need* to have significant anti-squat. HP+idler analog bikes can get by with lower anti-squat and therefore lower PK, so we have a common connotation that "idler == low PK". but it seems to not be the case for idler eMTBs.
while this might seem dumb or pointless ("why not just run a low pivot?") my feeling is that the idler still affords a rearward axle path which would cause completely non-viable amounts of anti-squat and PK without the idler.
or maybe this is my way or rationalizing why I'll probably run a Rimpact on an idler eMTB
my theory is that high-torque eMTBs just *need* to have significant anti-squat. HP+idler analog bikes can get by with lower anti-squat and therefore lower PK, so we have a common connotation that "idler == low PK". but it seems to not be the case for idler eMTBs.
while this might seem dumb or pointless ("why not just run a low pivot?") my feeling is that the idler still affords a rearward axle path which would cause completely non-viable amounts of anti-squat and PK without the idler.
or maybe this is my way or rationalizing why I'll probably run a Rimpact on an idler eMTB
mhueschen
New Member
thanks.Could always use DT 240 or 350 hubs' DF Technology.
after looking into hub-based anti-PK solutions a bunch this week, my current feeling is that a crank-spider PK solution is more preferable for me:
1) hub-based degrees of freedom (DF) need to be multiplied by the gear ratio to determine crank-based degrees of freedom. a Sidekick with 12deg at the hub turns into 18deg at the crank in a 52t granny on a 34t chainring. that is a huge amount in my experience - having run an Ochain I found I liked 6deg and found 9 and 12deg to often annoy me.
hub-based solutions seem to exhibit the exact opposite gear-ratio scaling of what I want. they have more DF in large cogs which are used for climbing and where I want less DF. they have less DF in small cogs which are used for descending. at high speeds it is adequate, but it forces a choice between poor climbing, or PK in middle cogs.
2) PK-hubs do not reduce chain whip, and could even make it worse. Sidekick and DEG-DF don't have a spring. so a whipping chain would seem to "extend" them, allowing even more whip. an Ochain or Rimpact provide dampening where it counts - between the chain and the cranks/feet.
3) greater unsprung mass for a PK-hub, degrading suspension. not a huge difference, but worth noting.
Just on your point 3,with the dt Swiss df hub, there's no increase in unsprung weight compared to a regular dt Swiss deg hub. I think your other points all stand though
PaulH2B
Member
I’d be interested in your feedback if you actually get the chance to try out the Rimpact device. From what I’ve heard from someone who tested it on his bike‑park MTB (non‑eMTB), it noticeably reduces pedal kickback, but chain noise and chain slap actually increased. The reason seems to be that the spring pulls the chain — and therefore the freewheel — back into position quite forcefully.
Although you have more freedom of movement during suspension travel (it feels deeper, like without a chain), it feels somehow unpleasent going through rough sections with lots of roots, he reported. I would be interested in hearing more reports on whether others feel the same way.
John_likes_bikes
Well-known member
I believe the pedals easily rotate backwards because there's little to no friction, compared to a mtb, which has the cassette freewheel holding is still. I don't think it has any relation to pedal kickback.
By necessity and choice I try to be in higher gears when descending and KB is going to occur but if you're in slow tech ratcheting and pedal kick a drop yeah, it's rough on the feet no matter what style frame.
I too can hear my sidekick clanking away, one of the reason I preferred the ochain. Much more naturally feeling.
I guess I was under the impression that a true high pivot (these are really mid-pivots we are discussing in this thread) that the entire point was that you could have high anti-squat AND no pedal kickback just because the distance from the idler wheel to the rear axle did not grow under compression, aka no chain growth.
doochenozzle
Member
Yes. Riding a Druid CorE. Not zero chaingrowth but certainly less. Love it. I can’t tell if the voodoo of high pivot is more to do with rearward axle path or managed/reduced pedal kickback. Likely both.
mhueschen
New Member
oh, that's interesting. I wonder if he was using the firmer springs in the Rimpact? Pinkbike seemed to feel that the firmer springs damped the chain slap better for them, but had the downside of being stiff enough that they oscillated during the pedal stroke, instead of just staying "bottomed out" though the full rotation of the cranks. my Ochain is easy to bottom out and I like that, so I am drawn to the softer spring option on the Rimpact.
whenever they come available and I get my hands on one, I'll post an update
mhueschen
New Member
I understand your point but I wonder if you're imagining other forces (wind / vibration) to be causing the one-direction rotation? my theory from half-watching the rear Teslacam while driving was that the rotations occurred only on big thumps where the car hit something, bouncing the bike upwards and compressing the suspension. it seems to be the same effect as when I slam the rear tire on the ground, as you can see in this short vid.
mhueschen
New Member
I went down a rabbit hole about this last night and have improved but as-yet incomplete understanding. I hope I'm not restating stuff others know to be obvious!
I believe there are 2 components of anti-squat:
1) chain driving force
2) ground driving force
(1) is the chain pull extending the swingarm. I believe this is 1:1 related to PK, meaning more of one yields more of the other.
(2) is created by the forward movement of the rear wheel contributing to swingarm extension, because of the swingarm angle created by the high pivot. as the pivot gets lower, this effect is reduced.
so, in theory you could have a very-high pivot design with an idler at the instant center, and prioritize zero-(1) and zero PK. and the high pivot would allow adequate (2) to give satisfactory AS.
I had previously thought that Forbidden prioritized this zero-Pk, zero-(1) design. but that appears to be mistaken. on the eDruid in particular, with the mid-pivot (which I understand to be helpful+practical for achieving other frame-design goals), I believe (1) is dominant, and (2) is present but not so substantial. and the idler placement is a big part of this...
so I guess this makes me wonder about a high-pivot concentric-idler motor-gearbox-unit eMTB of the future
for now, I guess I'll content myself with running a Rimpact and making use of the already-quite-adequate Avinox power... and hitting the gym to deal with wrangling the heavy bike
