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OChain “chainless” chainring spider

slyfink

Turbo Monkey
Sep 16, 2008
9,289
5,029
Ottawa, Canada
wasn't there a racer (I want to say Gee), who had a spacer in place of a cog on his cassette so he could shift into a "gear" that didn't engage the freehub? As I recall, it was a one-off, maybe in the last 2 years or so?
 

captainspauldin

intrigued by a pole
May 14, 2007
1,263
177
Jersey Shore
wasn't there a racer (I want to say Gee), who had a spacer in place of a cog on his cassette so he could shift into a "gear" that didn't engage the freehub? As I recall, it was a one-off, maybe in the last 2 years or so?
Canyon had something like that for Troy... I don't think it ever went anywhere tho...
 

Westy

the teste
Nov 22, 2002
54,235
20,016
Sleazattle
Chain wrap around a cassette doesn't really work that way. Unless you're putting derailleurs on full suspension fixies.

Which I wouldn't put past you.


You ever bounce the back wheel of a suspension bike on the floor of your garage and see the cranks get pulled backwards? Ever notice that's not what happens when coasting downhill with you on it?

I'm not saying what's being taken up by the derailleur is huge, but it's not nothing. Some bikes more pronounced than others obviously. And since it relies on the singular rotation direction of a freewheel hub, it's not exactly 1:1. And clutch derailleurs only provide significant friction in one direction.

Imagine how fast bikes would be if we got ride of all the energy absorbing devices that moved with the suspension?
 

Electric_City

Torture wrench
Apr 14, 2007
1,993
716
fuckin' nerds..
No shit. Last time I put any thought into this was never. It seems like around here it's not about riding your bike anymore, but anal-izing the back pressure of a derailleur on your high speed rebound and the extra 4.1% of pressure it takes to engage brakes.

Do you guys even ride bra's?
 

dump

Turbo Monkey
Oct 12, 2001
8,195
4,419
No shit. Last time I put any thought into this was never. It seems like around here it's not about riding your bike anymore, but anal-izing the back pressure of a derailleur on your high speed rebound and the extra 4.1% of pressure it takes to engage brakes.

Do you guys even ride bra's?
Woo is snowed in. Clearly not riding. Take anything w/ a grain of salt.
 

kidwoo

Artisanal Tweet Curator
Imagine how fast bikes would be if we got ride of all the energy absorbing devices that moved with the suspension?
I rely very heavily on those energy absorbing components these days. It's rough out there!


Woo is snowed in. Clearly not riding. Take anything w/ a grain of salt.
Rode for 3 hours sunday. Our winter is sucking. Not like that matters.
 

shirk007

Monkey
Apr 14, 2009
499
354
Who wants to go full nerd on this?

Not my calculation but this recently came up in a PB thread so thought it would be good to share here.

Poster R-M-R on PB.

Pedal kickback while coasting is a myth and this can be calculated:

• Take the circumference of the wheel.
• Calculate the maximum pedal kickback in any given sprocket combination, in degrees.
• Multiply (kickback / 360°) × circumference. This is how much the wheel would have to rotate to negate all kickback.

• Take the speed you usually travel while using the sprocket combination from the previous calculation.
• Calculate how long it would take you to travel the distance from the previous calculation. This is the maximum allowable time in which to fully - from top-out to bottom-out - compress your shock for any pedal kickback to occur, let alone enough kickback to be a problem.

• Divide you shock's stroke by this time you just calculated. That's the shaft velocity of the slowest possible impact that will produce any kickback. You will find this shaft velocity is unrealistic. If your shock goes from top-out to bottom-out in 0.03 seconds, for example, you have bigger problems than a little kickback.

But wait, there's more!

This calculation didn't even account for any delay in the engagement of your hub's driver. If the average engagement is, say, 10°, then the average amount of engagement is 5°. This takes 5°×(rear/front sprocket) off the average possible amount of kickback in a full travel impact, making the situation even less likely to produce any kickback, let alone problematic kickback.

Similarly, it's essentially a myth that the derailleur clutch can interfere with suspension. I'll be more brief this time:

1. The clutch doesn't move immediately and often doesn't move at all.
2. If the clutch does move, the clutch breakaway occurs after the suspension starts to move, so it doesn't contribute to "breakaway" force.
3. If the clutch does move, the static friction does hamper suspension performance, but the force is so small, relative to everything else happening in an impact event.
4. Once the clutch is in motion, the dynamic friction and spring force simply add to the spring and damper forces of the suspension.
5. The motion of the clutch is so small. Work = force × distance. The force is small: you can easily move it with one finger; think of how small that is, compared to the impact. The distance is small: the clutch rotates only a few degrees. Thus, the work to overcome is it virtually nothing.
 

Lelandjt

Turbo Monkey
Apr 4, 2008
2,508
822
Breckenridge, CO/Lahaina,HI
If pedal kickback existed would it be lessened by being in taller gear? Or would that depend on the frame? On a few bikes that are known for it I feel like the suspension is plusher in 10th gear than 5th. It would seem like in a low enough gear the freewheel could engage and you'd feel it, but in a tall gear the cog set can't be rotated quickly enough by the suspension for the pawls to catch.
 

kidwoo

Artisanal Tweet Curator
On most of them yes, but it depends on the frame. Most modern bikes that are worth a shit have gotten it pretty minimal.

Just put your bike in a stand and take the shock off and cycle the thing in different gears.

Then do it while holding a pedal in place. On the frames you're probably thinking of you'll see the drivetrain unwind more drastically to feed out slack.
 
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Lelandjt

Turbo Monkey
Apr 4, 2008
2,508
822
Breckenridge, CO/Lahaina,HI
Pinkbike had a product release article on this yesterday so it was thinking about it again and went back to reread Woo's post. So is it safe the say that you can avoid pedal kickback by being in a tall gear and not riding one of the very few current bikes with lots of chain growth? If so, than the people who think they feel a difference with the chain removed are only reacting to the lack of noise and unsprung weight?
 

kidwoo

Artisanal Tweet Curator
It's 2020. So unless you buy an orange, don't worry about pedal kickback. It's so minor on most bikes built these days it's a non issue. And on any ones were it's significant just don't pedal in g-outs. For the millionth time, chain growth gets taken up by the derailleur.

Did you read the part about putting a bike in a stand, taking the shock off and cycling the suspension? Then doing it again while holding a pedal in place?

Then put all that shit back together and go do two ones, one with a chain and one without.

That will answer all your questions :D
 

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,346
1,587
Warsaw :/
Just take your shock off and hold your pedal while cycling the suspension. Its not complicated. Chain kickback doesn't happen on any suspension design work a damn because the derailleur unwinds.
I thought the idea was getting an idler like suspension feel where your chain tension doesn't influence how your susp works? Or am I wrong? Because I know some people who praise not feeling your chain, those people ride specialized's...
 

Lelandjt

Turbo Monkey
Apr 4, 2008
2,508
822
Breckenridge, CO/Lahaina,HI
I thought the idea was getting an idler like suspension feel where your chain tension doesn't influence how your susp works? Or am I wrong? Because I know some people who praise not feeling your chain, those people ride specialized's...
Idler bikes still have some chain growth. Otherwise they'd have no anti-squat and pedal like concentric bikes.
 

Westy

the teste
Nov 22, 2002
54,235
20,016
Sleazattle
It would be more interesting to track the reduction in both frequency and amplitude when saying hee-yaa (here).
 

kidwoo

Artisanal Tweet Curator
Confirmed everything I thought.
It's true. Steve wakes up at 2pm

Take aways: Use the lightest and shortest chain (this means use the smallest cassette you can). Use a top and bottom guide with the clutch turned off. Be in a tall gear.
All of which you would have seen personally if you'd done what I said in a bike stand :rofl: