Pedals rotate when they shouldn't
07-19-10, 03:12 AM
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Pedals rotate when they shouldn't
Recently, I noticed that my pedals rotate even when they shouldn't. For example: when I walk with my bike to the car, pedals rotate. True, they rotate much slower than the rear wheel. Still they rotate! Today I checked while descending, and it did happened (by moving my legs from the cleats). I do not feel this while riding (legs in the cleats), probably because the pressure is relatively low.
I believe it shouldn't be like that. Is this such a problem that I should not ride my bike before it is fixed (I simply don't have the time to step by a LBS this week)? I think the time come to replace the chain, can this be the cause for this phenomenon?
Other ideas?
THanks in advanced.
I believe it shouldn't be like that. Is this such a problem that I should not ride my bike before it is fixed (I simply don't have the time to step by a LBS this week)? I think the time come to replace the chain, can this be the cause for this phenomenon?
Other ideas?
THanks in advanced.
07-19-10, 03:32 AM
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Hopefully, it just means your drivetrain has such low friction that the minimal drag from a normally operating freewheel is enough to turn it.
If you pull your rear wheel and the freewheel spins fine, it's a good sign.
If you pull your rear wheel and the freewheel spins fine, it's a good sign.
07-19-10, 07:41 AM
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Basically it means that the freewheel drag in the rear wheel is greater than the combined drag of the BB and chain running through the RD.
It could be a good thing as Kimmo suggests, or it could be that the freehub is a bit stickier than it needs to be. If it's been a long time since any service has been done, or if it's a new development, I suspect the latter, since friction tends to increase, not decrease.
It isn't a serious problem, and if the wheel spins freely with the bike off the ground you can ignore it, otherwise you might want to clean and lube the freehub.
BTW- before you take anything apart, look behind the cassette. Often little bits of string or other road crud get caught and wound around the hub behind the cassette creating friction between the two parts. Cleaning this out usually solves the problem.
It could be a good thing as Kimmo suggests, or it could be that the freehub is a bit stickier than it needs to be. If it's been a long time since any service has been done, or if it's a new development, I suspect the latter, since friction tends to increase, not decrease.
It isn't a serious problem, and if the wheel spins freely with the bike off the ground you can ignore it, otherwise you might want to clean and lube the freehub.
BTW- before you take anything apart, look behind the cassette. Often little bits of string or other road crud get caught and wound around the hub behind the cassette creating friction between the two parts. Cleaning this out usually solves the problem.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
07-19-10, 09:23 AM
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you could thoroughly flush and re lubricate the freehub with very light machine oil,
but then you have to keep it up more often .. frequent re lube intervals.
Add a heavy pedal?
but then you have to keep it up more often .. frequent re lube intervals.
Add a heavy pedal?
07-19-10, 10:18 AM
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It appears this is a known problem with Mavic wheels. Got advised not to ride until being fixed as it can result (if friction gets higher) in overload on the chain and harm the diversion components.
07-19-10, 08:55 PM
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This just is a sign of a dirty freehub body. Pull the freehub and clean and relube with heavy mineral oil. In the base of the Mavic hub there is also a rubber seal that has two sections, one thick and one thin. You can trim off the thin part to remove some of this pedal assist as well, it drags a little.
