Help Needed

[Walleee]

So I managed to hook the teeth on my rear 12t fixed cog

I got a new 12t cog, and tomorrow im going to attempt to remove the old one. Looking on tartybikes they recommend that you do not use a chain whip to remove the cog as it can be very tight. This I understand after attempting to remove it with a g-clamp........It snapped shortly after beginning to turn.

I have read on another thread, that one can clamp the cog in a vice, and turn the wheel but my concern with this is that surely im putting stress on the spokes and hub?? Is this something which is negligable and I can carry on and pull as hard as possible, or should I seek alternative removal methods?

Im not going to the bike shop for this one.

[ZeroMatt]

It is pretty dodgy but it worked for me, don't do it unless its the last resort, i clamped mine in between some pieces of wood so the teeth dug into them so it wouldnt slip.

[dave85]

There are no methods which dont involve large amounts of force on the spokes, but I don't know anyone who's knackered a wheel through this. Best way is wrap an old chain round it then stick a big pair of stillsons over the chain. Get someone else to hold the wheel and give the stillsons some pasty.

[bee_]

be a man, use your teeth!

[smelly joe]

When i had to remove the 12 tooth cog on my onza, i heated the cog up with a blow torch and then put a rather large chain whip on and pulled it. it came off but took a lot of re-heating and pulling.

[Mark W]

Our local bike shop wiry-but-strong guy (every shop has one ) took mine off by wrapping a length of chain around the cog to protect it, then clamping it in a vice, and turning it ridiculously hard. Worked easily enough ('specially from my p.o.v., 'cos I didn't have to do shit).

[Walleee]

Well, all done now, I took an angle grinder to it, the idea about the wood or chain to prevent teethe from getting destroyed is most definately worth the time, I forgot to check this thread this morning when I went out, and didnt protect the old cog, as soon as they are in the vice they break off once any sort of pressure is applied.

I tried it, along with two lecturer's and a technician from 'up the country' (i.e. big, burly, tank-like) and none of us could get it off turning the wheel, while we were turning, the spokes flexed alot, so much that i decided enough was enough.

Brought in the angle grinder, ground down so i could just see the threads, got a hammer and a bar, and whacked the cog causing it to fracture, then it unscrewed by hand with minimal damage to the threads.

I'll put up a picture once I get my phone back to show, im suprised there hasn't actually been more of these threads about, that was a proper pain in the arse.