Crank spins forward intermittently during coasting(freewheeling)

[SniperX]

Recently I noticed that when I put the bike on a stand and spin the rear wheel forward(coasting or freewheeling), the crank will move forward intermittently without mi pedaling as I am not even siting on the bike. is this normal? (zipp 404s being used) I tried to do this on another bike and it dooesnt . the rear wheel spins smoothly n the cranks n pedals of the bike stays still without moving forward. . so is this normal or someting is wrong ?

 

[artemidorus]

This is normal for some wheels.

 

[daveornee]

Recently I noticed that when I put the bike on a stand and spin the rear wheel forward(coasting or freewheeling), the crank will move forward intermittently without mi pedaling as I am not even siting on the bike. is this normal? (zipp 404s being used) I tried to do this on another bike and it dooesnt . the rear wheel spins smoothly n the cranks n pedals of the bike stays still without moving forward. . so is this normal or someting is wrong ?

Freehubs normally have some drag and will cause that "symptom" on a free running system like bike on a stand.

 

[dgregory57]

Each click you hear is accompanied by a mild pressure for the cassette to move with the wheel. When that pressure exceeds the forces resisting it (BB and derailleur pulleys) the cassette will move with the wheel, and thus the crank will move. To demonstrate, remove the chain and your cassette will happily rotate with the wheel.

If you can spin the wheel while it is out of the bike and hold the cassette from spinning pretty easily, then all is well, you just have a very free moving crank. It could actually be a good thing.

 

[brycer]

Go and service your freehub - if you have described it correctly it is a symptom of **** building up causing drag and thus the cranks turn when you are freewheeling. If its Mavic they have a good guide on how to service it on their website. Just be careful that you keep the pawls under control so they dont go flying when you slide the freebody off.