Hey,

I am running a single speed on a flip flop hub and would like to give fixed a go. The ss is 16t and the fixed cog is 14t. My problem is when I flip over to the fixed cog the chain tension seems to be a bit loose. Do I need get a fixed cog that is closer in size to the ss?

Thanks
James

What do your dropouts look like?

Same chain length but different cog size will mess up your chain tension...two teeth = 2 links = an inch difference.
I'd definitely get a 15t to match your 16t a bit closer.

Thanks, the drop outs are horizontal but with the freewheel the wheel is pushed all the way back so would not be able to move it further back with the fixed cog. Will give a larger fixed cog a try.

You can fix the chain and move the wheels closer OR you can use a chain tensioner, both of which is cheaper and less wasteful than getting a new cog =)

If you put the same size cog on the other side you can eliminate the problem entirely.

Do people seriously need to be told to remove a chainlink here?

it's more like half an inch, since not all teeth of the cog and chainring are engaged at once. More or less half of the teeth in the cogs are engaged.

It might be possible to make a chain that fits both cogs by using a half link chain.

Yes, they do.

REMOVE A LINK IN YOUR CHAIN

If the slots are long enough, take a link out of the chain to move the cog forward enough so that you don't run out of slot when you use the smaller cog. The closer in size the cogs are, the less of an issue this is, but most horizontal track dropouts are long enough to accommodate a 2-tooth size difference without a problem.

Huh. I wouldn't have figure that one.

Thanks everyone, I'll remove a link, to move up the wheel when using the freewheel and move the wheel back into the dropouts when using it fixed.