Marc7200

I am building a fixed gear bike out of an old ten speed frame for the first time and after feeling like an idiot at bike shops today I am wondering if anyone can enlighten me on chains and cogs.

Taking Sheldon Brown's advice I purchased a SRAM PC-58 3/32 inch chain off the internet for my fixed conversion. I bought a Dura-Ace 16 tooth track cog from a local bike shop and mounted it on my hub and started to install the chain. The chain did not mesh on the cog, it seemed like the links were too long and the rollers did not line up with the teeth. The chain did fit on the Rocket chainring and the Shimano BMX freewheel on the other side of the flip flop hub.

I went to a different (much closer but no fixed gear parts) bike shop with the cog and tried a 1/8 inch chain. This chain did not mesh on the cog either. The wrench then tried a 3/16 inch chain and this one meshed fine. He looked up the cog in his catalog and it said it was compatible with 3/32 and 1/8 inch chain.

Thinking I had a mislabed cog, I then went to the original bike shop and told them the cog only fit a 3/16 chain. They said no, the 1/8 inch chain would work, and they took a 1/8 inch chain off their shelf and it meshed with the cog.

Can anyone explain what happened? Are derailer, BMX, and singlespeed chains different? When I get home with this new 1/8 inch chain will it fit my Rocket ring that the PC-58 chain fit?

BoozyMcliverRot

i have the same problem putting a 8 speed chain on a generic cog and acs freewheel(fixed/free) wheel on a conversion im doing

queerpunk

there are a couple different types of chain:
1/8".
3/32"
9- and 10-speed chain. this **** is super narrow and we're not going to talk about it.

Now, cogs and chainrings that are made for 3/32" chain will work with a 1/8" chain just fine. but a 3/32" chain is not going to work on a cog or chainring that's made for 1/8". why? because you can't put a size small sweatshirt on a linebacker - follow?

lots of cogs come in either 3/32" or 1/8". it sounds like you're not sure which you got, and it sounds like you got 1/8". i don't know why this other bike shop's 1/8" chain didn't mesh on it, and i certainly don't know why there's a 3/16" chain in the equation - that's overkill.

there's also an issue of wear. i put a new chainring on my bike with an oldish chain, and it sounded horrible and every now and then the chain would delay before snapping into the chainring. felt the chainring for burrs, but that wasn't it - the chain was worn. "stretched," as they say, which just means that the pins get worn down so that the chain really is a little bit longer than it should be. when cogs, chainrings, and chains wear together, that's fine until you throw something unworn in to the mix - then their system is polluted and you need to start over. to avoid that, you want to put a new chain on when it gets all stretched out, so it doesn't wear your chainring and cog to the point where any other chain won't work well.

anyway: rocketrings will take a 3/32" chain, but they'll also work well with 1/8" chain - they're beefy. with your working 1/8" chain, you'll have a setup that should work fine.

dutret

9-speed at least is 3/32 I think shimano 10 is too but I've never used it. It is the exterior width of the chain that needs to be small.