Bicycle Mechanics - bACK WHEEL problem

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View Full Version : bACK WHEEL problem


ngordon
03-26-11, 11:19 AM
guys was looking for some info.

was cycling home last night and back cog was spinning and not moving back wheel.

managed to make it homecos it was intermittent but constantly kept spinning as if not making contact with hub of back wheel ?

any ideas ?

cheers


fietsbob
03-26-11, 11:40 AM
Information vacuum.. need more details Type/ brands /models/pictures?

with out any such info i'll say .. take it back to the dealer or any other Real bike shop.

FBinNY
03-26-11, 11:51 AM
This is most commonly a symptom of a freehub (or freewheel) ratchet not holding. What is happening is that the pawls in the ratchet mechanism (concept diagram) (http://www.technologystudent.com/cams/ratch1.htm) aren't engaging properly.

Common causes are rust or corrosion, stiff grease or dried oil gluing them, weak or broken return springs, and chipped pawls or ratchet ring. If you're lucky it'll respond to a flush and re-lube, if not replacement is the only option. The exact method for dis-assembly and service depends on your particular hub. If you're unfamiliar with servicing your hub, read some of the available tutorials on freehub or freewheel service for your model hub, or visit your local shop and hope for the best.

BTW- probably 9 out of 10 times, a flush and lube fixes it, so the odds favor an inexpensive repair.


coldfeet
03-26-11, 02:31 PM
Can also be temperature related, I've had a freehub fail to engage after spending the night at -25C in the garage. We do need more info though, conditions, freehub/freewheel, age etc.