sprocket on my grandson's bike

roboanna | 17:00 Sun 14th Feb 2010 | How it Works

5 Answers

My grandson's rear wheel sprocket has just decided to go freewheel!. Nothing "grips" and the poor lad pedals away to no avail. can this be fixed by me - someone who is competent with a spanner , or , do I give it to the local bike shop to fix? The sprocket has several cogs or gear wheels,
. Any help much appreciated. ta

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lslowry

Sounds like the pawls have gone or got stuck in the cog. i'm no expert but you could try oiling it for a start, it might just be a lack of it roboanna.

roboanna

Question Author

ta very much will have a go.

Clanad

It's unlikley lubrication will solve you're grandsons problem.

He'll tell you that it has always "freewheeled" when he pedals backward. (A normal design characteristic, which is the cause of having handbrakes on the handlebars). Now (especially if he's the typical aggressive rider, like our 13 year old) he's caused something to shear in the gear/axle mechanism.

First thing is determining what kind of mechanism it is... 'Thread-on Freewheel' or 'Freehub'... here's a site than can help you with that: http://sheldonbrown.com/free-k7.html ...

If it's less expensive bike,it's likely to be the 'thread-on hub type, in which case the most likely scenario is that (whether it's a threaded type or more likely a Shimano Freehub (very prolific)) is that the splines have failed and will need to be replaced. Often the spline failure only affects one set of gears so your grandson may be able to shift the gears and get one or more to still engage.

You could, as the article suggests, simply buy a cassette of gears and replace them... but that's going to take a special wrench. Sorry I can't be more helpful... Best of luck!

mjwman

Rather than oil use WD40 as it is thin and creepy.
If that fails you can change it but you will probably need the special rmoval tool. If you have a go with hammer and drift it will wreck it but no matter the new one will screw on ok.

roboanna

Question Author

thanks all. IVe done it!!- wd40 - seems to have released the clogged up spines and Jamie is now peddling for England. Not been on this part of site before and my first prob is solved immediately. ta

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