Just building a singlspeed up and was wondering if a 9 speed chain would be ok? I have a few knocking about and it would save me buying one. I guess its not as strong as a proper SS chain though. Would an 8 speed chain be a lot better? as LBS had some on offer for a really good price. I hear about people snapping chains on gaared 9 speed bikes all the time so single speed seems to me like a good chain may be crucial!

needs to fit on your chainring/ sprocket

you cant exert any more force on a SS drivetrain than geared – so if it fits use it.

seth – what thomthumb says, but also an 8 speed chain is 3/32", and is the "usual" chain for SSing.

If you're really worried about snapping chains, fit a 1/8" track chain….

I'm using a 10 speed Dura-Ace chain on my SS (due to a slight mis-measurement when fitting it to my road bike) without problem.

I've done quite a lot on singlespeeds with 8 and 9 speed chains and they work fine. I run them for inter-operability with other people's bikes and because I snapped a SRAM singlespeed chain twice in the first 3 rides.

From other people's experiences, though, my SRAM SS chain experience seems to be an anomaly.

8 speed will generally fit the singlespeed sprockets better than 9 speed.

Multi-speed chains is where most (all?) of the develoment money is going for chains, no need to worry about strength, IMO.

Lots to read from Surly Bikes here: http://www.surlybikes.com/spew3.html