Help, my bike is broke.

[Srengam]

There's something wrong with my bike.

I've cycled to work today, and as I got to the bottom of a good long hill (which I rolled down), when I started pedalling the back cogs went round, but the wheel just stayed put. So I got off, and started turning the pedals by hand and the bike stayed put until after a few seconds it "caught" and then started working again. This kept repeating but it's getting longer and longer before "catching".

I've got to cycle home after work at 10pm tonight, and I don't want to push it up that hill either.

Does anybody know what's wrong with it?

My best guess is that their's a ratchet somewhere in the cog system, and it's sticking in. Could giving it a good hot jet-washing solve it?

 

[touch]

My best guess is that their's a ratchet somewhere in the cog system and it's sticking in.

Yes.

Could giving it a good hot jet-washing solve it?

No.

Depending on what type of gears you have (how many sprockets are on it?) you might be able to take it apart and clean/re-grease it. You wont be able to fix it by washing it externally. It's also possible that the pawls (the teeth bits of the ratchet) are worn out, in which case you would need some new parts (either new pawls, cassette or hub depending on what setup you have).

 

[Jonny69]

I fixed a really old one that was doing exactly as you described by soaking the ratchet mechanism in petrol to dissolve out the old grease or oil, allowing it to dry and then soaking it in oil to relubricate it. I thought it was knackered at first because the bike had done some miles over the years, but a clean and lube made it as good as new again.

Depending on the age of the bike, it is most likely that the gears come off as a cassette. The splined hub that the cassette slides onto can be removed from the wheel and either dismantled and cleaned, soaked and cleaned or simply replaced. If you replace it you just need to replace it like for like, which a bike shop will be able to identify