Drive train friction

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DaveReading

Don't suffer fools gladly (must try harder!)
Location
Reading, obvs
As a rule-of thumb, if I spin the pedals backwards and let go, how many revolutions of the pedals would it be reasaonable to expect before they come to a stop?

I'm a little concerned that there seems to be excess friction somewhere in my drive train (possibly the jockey wheel/s), so I'm interested in knowing how I can judge whether there is.

I appreciate that there is probably more inertia in my 8-speed setup than in a 10/11-speed, so I'm happy to factor that in.
 
I suppose how fast/hard you spin them would make a difference... mine spin 67 times...
 

Salty seadog

Space Cadet...(3rd Class...)
As a rule-of thumb, if I spin the pedals backwards and let go, how many revolutions of the pedals would it be reasaonable to expect before they come to a stop?

I'm a little concerned that there seems to be excess friction somewhere in my drive train (possibly the jockey wheel/s), so I'm interested in knowing how I can judge whether there is.

I appreciate that there is probably more inertia in my 8-speed setup than in a 10/11-speed, so I'm happy to factor that in.



Not many. If you get 5 you'd be doing well. It will make no real world difference. If you have a problem that mattered you'd feel it while pedaling.

Having said that I also get about 67 revolutions.
 

Cycleops

Legendary Member
Location
Accra, Ghana
I'm maybe mean cranks not pedals? If you mean pedals that will tell you nothing. You need to take into account friction in the BB and what sort of chain line you have. Too many variables for a conclusion.
 
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ColinJ

Puzzle game procrastinator!
I suppose how fast/hard you spin them would make a difference... mine spin 67 times...
You must be talking about a fixed gear bike? My Cannondale CAAD5 is a pretty nice bike in good working order but I reckon the cranks would only do about 5 revs with a good backwards flick.

Yes - I just went and tried it - no more than 5 revs.

It's a weird test - not something that I have ever felt the need to do!
 

Heltor Chasca

Out-riding the Black Dog
Some jockey wheels are designed to spin in a certain direction so spinning backwards surely isn’t a good control. So too are all the teeth on chain rings and cassette. Some chains too.

Besides, you ride by pedaling forward so unless I’m missing something, I don’t understand your mission and how your findings will come up with a conclusion.
 
OP
OP
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DaveReading

Don't suffer fools gladly (must try harder!)
Location
Reading, obvs
If you have a problem that mattered you'd feel it while pedaling.

But would I, though? I'm not suggesting anything is seized, just that there seems to be a tad more drag than I would expect.

It's a 15 kg tourer with M+ tyres, so I'm already used to a fair amount of resistance when I'm pedalling. :ohmy:

It's a weird test - not something that I have ever felt the need to do!

If you can suggest a better/easier way to judge whether a drive train is moving as freely as it should, I'll be happy to try it.
 

Salty seadog

Space Cadet...(3rd Class...)
But would I, though? I'm not suggesting anything is seized, just that there seems to be a tad more drag than I would expect.

It's a 15 kg tourer with M+ tyres, so I'm already used to a fair amount of resistance when I'm pedalling. :ohmy:



If you can suggest a better/easier way to judge whether a drive train is moving as freely as it should, I'll be happy to try it.

In all seriousness, by giving it a good whirl backwards and letting go, like I said earlier it will all come to a stop very quickly. 5 revs or less. There is not much you can diagnose from doing this. It's just how it is. I think you are overthinking it.
 

JhnBssll

Veteran
Location
Suffolk
Free spinning won't give any real indication of loaded friction, it's too easily affected by things like bearing seals etc.
 
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