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chains and suspension - i have questions.

'size

'size

Turbo Monkey
May 30, 2007
2,000
338
AZ
so, chains break and people still win or place really well in races. we know suspension works 'better' without chain tension but is there any validity to the below? i know canyon was testing a system that decoupled the entire freehub but i don't know enough about the interaction between suspension, gearing and derailleurs to know if the below would give essentially the same outcome.



warning : possible chris porter trigger.
 
Udi

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
To my understanding that's a myth - because freewheeling pulls away from the direction of engagement. This means while you *can* get pedal feedback in certain circumstances, the freehub needs to catch up for that to happen (usually only likely if going slow AND using a lot of travel), eg. going off a slow, large drop. Faster engagement hubs will cause this to happen at higher forward velocities, so there may be benefit to not having super-fast hubs, depending on the chaingrowth of the bike (obviously the other variable, aside from the currently-selected gearing). I just woke up so feel free to correct me if I made something up there.

I think for proper DH courses (ie: gravity surplus) no chain often nets faster runs because not being able to compensate mistakes (w/ forced acceleration) results in better braking technique. Partly psychological + partly physical benefits (braking less has a myriad of side effects - better chassis stability, more consistent geometry, less fatigue, better bump absorption, etc). Removing the chain also knocks 1/4kg off the bike at least, which isn't entirely insignificant in races won by split seconds.
 
Jm_

Jm_

sled dog's bollocks
Jan 14, 2002
20,065
10,630
AK
Seems rather uncontrolled and bouncy the few times I’ve done it.
 
4130biker

4130biker

PM me about Tantrum Cycles!
May 24, 2007
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I Agree w Udi, i think just a different way of saying it- that focusing on maintaining momentum through better choices/ less braking probably has most to do with it.

However, I would be interested to see a well-done experiment on a high speed smooth motorway on a DH bike; pedal vs no pedal... My intuition is that at really high speed, thrashing about, smashing the pedals on a DH bike may not result in anything but tiring the rider.
 
kidwoo

kidwoo

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Aug 25, 2003
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You're fighting the spring on the derailleur. If you haven't noticed how much better your suspension works without a chain vs. a clutch derailleur especially, you get a punch on your geek card. One more and you lose it.

You never get full pedal kickback because the spring loaded tensioner in the derailleur gives to loosen the system.
 
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4130biker

4130biker

PM me about Tantrum Cycles!
May 24, 2007
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On that same note, sprinting on a bike usually involves lots of the bike tilting side to side...
I wonder if the frequent transition from center to side to center tread repeating on DH tires with big blocky side knobs minus transition knobs (for good reason) is netting worse rolling resistance overall and negating positive effects of pedaling on high speed motorways?
 
B

Bike078

Monkey
Jan 11, 2018
599
440
kidwoo said:
You're fighting the spring on the derailleur. If you haven't noticed how much better your suspension works without a chain vs. a clutch derailleur especially, you get a punch on your geek card. One more and you lose it.

You never get full pedal kickback because the spring loaded tensioner in the derailleur gives to loosen the system.
Click to expand...
If I recall correctly gwin in leogang and rachel in ft. bill remarked on how the suspension somehow worked better or was plusher?

I tried a chainless run after my derailleur hanger broke. It felt weird not having the chain to provide resistence when you're standing on the pedals. Otherwise the run went fine. I was on a horst link bike at that time.
 
HAB

HAB

Chelsea from Seattle
Apr 28, 2007
11,589
2,021
Seattle
kidwoo said:
You're fighting the spring on the derailleur. If you haven't noticed how much better your suspension works without a chain vs. a clutch derailleur especially, you get a punch on your geek card. One more and you lose it.

You never get full pedal kickback because the spring loaded tensioner in the derailleur gives to loosen the system.
Click to expand...
And the clutch, if you've got one of those. It makes a real difference.
 
kidwoo

kidwoo

Artisanal Tweet Curator
Aug 25, 2003
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For sure. That's the biggest difference if anyone wants to do the pepsi challenge. If you haven't ever taken your chain off for a run you know really well, do it. Even non-clutch derailleurs provide plenty of resistance.



Especially if you're still riding some piece of shit high forward single pivot :rofl:
 
HAB

HAB

Chelsea from Seattle
Apr 28, 2007
11,589
2,021
Seattle
I kinda forgot how big a difference it makes until I assploded my RD on my DW DHR a bit ago and took a few Whistler laps chainless. It's a big difference
 
F

FarkinRyan

Monkey
Dec 15, 2003
611
193
Pemberton, BC
Huge difference, that's from someone still riding a piece of shit high-forward single pivot at Whistler. Also a huge mental difference as Udi said, knowing that you can't pedal to make up speed makes you rethink your approach to so many sections.
 
Udi

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
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100% agree on the clutch mechs adding resistance.

Because they use one-way bearings as the "clutch", they actually have very high breakway force compared to the dynamic resistance they offer. I prefer SRAM mech/shifters in general these days (for shifting performance / weight / etc), but Shimano's easily adjustable clutch design is definitely superior for not ruining suspension. The SRAM ones get pretty awful and sticky as they age too, is there a known way to adjust or rebuild them? I remember being told you could.
 
Electric_City

Electric_City

Torture wrench
Apr 14, 2007
2,047
783
kidwoo said:
You're fighting the spring on the derailleur. If you haven't noticed how much better your suspension works without a chain vs. a clutch derailleur especially...
Click to expand...
I've definitely noticed this on my hardtail.

In the meantime, Rockshox is going to release the Blackhawk rear derailleur w/adjustable compression and rebound with the Charger 3 damper.
 
vincent

vincent

Monkey
Aug 22, 2004
180
17
Bromont, Quebec
Udi said:
To my understanding that's a myth - because freewheeling pulls away from the direction of engagement. This means while you *can* get pedal feedback in certain circumstances, the freehub needs to catch up for that to happen (usually only likely if going slow AND using a lot of travel), eg. going off a slow, large drop. Faster engagement hubs will cause this to happen at higher forward velocities, so there may be benefit to not having super-fast hubs, depending on the chaingrowth of the bike (obviously the other variable, aside from the currently-selected gearing). I just woke up so feel free to correct me if I made something up there.
Click to expand...

I agree that for a bump to generate pedal kickback, it is heavily situational and makes the use of pedal kickback figures mostly out of context.
Cassette angular velocity caused by the various contributor of chain lengthening has to exceeds wheel angular velocity and the situation needs to be sustained until you "hit" an engagement point (how fast this happens depends on number of engagement points). Then, only then, tension in the chain occurs. Without having mapped a range of wheel speed, bump speed, gear selection and possible chain lengthening/travel profiles, which all influence whether chain tension happens or not, I can't tell for sure but I agree with you that it must be pretty much irrelevant for speeds above 20-25kph. I also really agree about the psychological effect.

However I think there are many situations where rider stability is already at stakes that should be considered, braking in low traction spots! Imagine coming fast into a corner where the braking zone is full of brake bumps, chances are high that your wheel will leave the ground when you are braking and the wheel velocity will drop a lot, probably even stop, then hitting the next bump, all conditions are there (slow wheel speed and fast suspension compression) for non marginal chain tension to occur.

I think it is important to remember that chain tension does not only translate in pedal feedback as chain tension can be released or limited in 3 ways, crank rotating backwards, wheel spinning forward and travel extension (or compression opposing force) and all three occurs at different levels. For sure crank seems to have the largest leverage on the system and manifest itself the most and wheel spinning forward is probably negligible but wheel extension force clearly manifest itself as wheel rate firming up.
 
profro

profro

Turbo Monkey
Feb 25, 2002
5,617
314
Walden Ridge
I like how on a dirt bike you can give the bike throttle to stiffen the chain when jumping to flat. Wish I could do that with a mountin bike :think:
 
'size

'size

Turbo Monkey
May 30, 2007
2,000
338
AZ
so allowing the chain to be 'disconnected' from the cassette (as in the video linked) will essentially do nothing in regards to suspension performance while moving at speed because other things still move and derailleurs. thanks all.
 
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vincent

vincent

Monkey
Aug 22, 2004
180
17
Bromont, Quebec
'size said:
so allowing the chain to be 'disconnected' from the cassette (as in the video linked) will essentially do nothing in regards to suspension performance while moving at speed because other things still move and derailleurs. thanks all.
Click to expand...
Maybe I was not clear in my first post, there will be performance change if wheel speed (not riding speed) is slow which happens quite often as you can lock up wheels riding fast in choppy terrain. So disconnecting freehub mechanism has definitely an effect, is it enough to have a big impact on the ride? let's say there are factors impacting the ride more, but I would be keen on experimenting with canyon system.
 
C

Cerberus75

Monkey
Feb 18, 2017
520
194
When I race a car and switched to metal bushings I had to change the spring rates. When I've tried the chainless ride the bike felt like the bike had a little less spring tention in the rear than needed. I tried this when I lost weight and hadn't changed out the coil yet so it was still closer to what I should have had. So the chain, deraillure and free wheel add tention...Is it measurable to factor in proper spring rate? VS trying to disconnect the chain with gizmos.
 
Udi

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Vincent makes a valid point, the rear wheel does leave the ground and come to a stop in larger braking bumps. The normal force on the rear contact patch drops heavily under braking as load shifts forward (= much easier to lock wheel), so it's not just the roughness, but the pitching moment which causes this. Each time the wheel re-contacts you would have some feedback effects, magnitude depending on the factors we already mentioned.

Addressing things like this is always a tradeoff with weight though - and the question should always be "where is this weight best spent?". In this case, using coil suspension and possibly a clutchless mech with a (full) chainguide will have more traction benefits than a chain disengaging system alone, and will offer benefits in many other scenarios not just this one. It also means no proprietary stuff to break. Canyon's other fancy system (geometry switcher) also offers benefits, but most riders I know have had it fail, and then bought the aftermarket kit to remove the system and save weight.

The biggest benefit of not having a chain IMO is that you end up braking way less (+ pick better braking points) which itself directly improves bump absorption, corner exit speed, reduces fatigue, etc. This is why some riders train without a chain, and go as fast or faster when they put one back on. Obviously there are many smaller-magnitude technical effects too, to find out the exact magnitude of each thing you'd have to do some detailed testing.

I think the bottom line is, the marketing makes pedal kickback sound like it's a constant issue, when really it's only a potential issue under specific circumstances. It's more likely that psychological / technique changes as a result of riding chainless (and the resultant physical impacts of those - they aren't imaginary!) cause the biggest part of any total improvement.
 
C

Cerberus75

Monkey
Feb 18, 2017
520
194
kidwoo said:
Watch for brosnan and the ghost gear sprint by accident. Won't be pretty. But will be hilarious.
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Funny you mentioned that and this product is available.

I was out riding yesterday on my spare rear wheel. The cassette nut threads were pretty worn and my 11t started free spinning. It did feel a little better on a chunky down hill. But wasn't pretty when I found out trying to mash out the hole on a turn.
 
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