London Fixed-gear and Single-speed

Hi all

Recently i finished building my first fixed gear bike and have been riding it a fair bit over the past 2 days. I went out for a ride into town tonight as i was peddling quite hard BOOM there was a big jerk/slip in the chain. Theres nothing wrong with the chain and it hadn't slipped off. I went a bit more and the same thing happened. I thought since some of you are experts on the matter you could maybe give me an insight as to what might wrong. Im guessing something to do with the rear hub/cog. I dont want to start striping everything off if i have no idea what im looking for. Any help would be much appreciated. Thanks.

sounds like you might have stripped it. not sure though. actually, yes, possibly. or cog not on tight enough and it jumped forwards.

as PJ said, loose cog/striped threads or v loose chain and it slips or worn chain and/or sprocket making the chain ride up the teeth and slip.

if cog is loose, it tightens itself when you put the hammer down. at this point, stop, get off, tighten up lockring, carry on.

ok thanks for the haste reply's i like dylan's theory as its cheaper. I recently cleaned and oiled the chain so perhaps i did not tension it properly. If it was striped would it look quite obvious. excuse my naivety i have never been through this before.

maybe your chain line isn't straight? is it skipping some of the cogs?

Hmm im not sure exactly what was happening. It was just slipping when i peddled. Didnt make much noise or anything. i just took the rear cog of just now to have a look and it seemed ok to me. Retensioned it and tried to stress it a bit and it seems fine so fingers crossed/hope to fuck its not the hub :) 2 days use out of it would be devistating.

How tight was your chain?

no visible slack

If the chain is tensioned well , Sounds like its definetely a loose sprocket.

Does the slip occur when pedalling fowards, or when backwards/resisting?

First happened when i was resisting pretty hard. Then again when i went forwards. Took the cog of last night couldnt see any clear sign of striping(It wasn't completely mashed). Seems good for now, fingers crossed, I'll take a wee ride and see how it goes. Thanks to all for your suggestions this forum has been a great help throughout my build. Cheers.

cliche, get yerself over to one of the drinks, someone'll take a look at it. Where are you (roughly)?

Would love to, shame it might take a few days I live in Edinburgh...

ok. if it's happening once reverse, once forward, and so on (as opposed to forward every time or reverse every time) then the cog is untightening, then tightening,then untightening,etc.

this is good as it means your threads probably arent stripped. Follow these instructions, then come back here and give me reputation points: +ve if it fixes the problem, -ve if your bike catches fire :-)

yeah baby, I've got no shame asking