How do I determine chain speed?
 

Howdy all. I recently purchased an Ultegra 10-speed chain to replace a 9-speed. But I discovered that the 9 presently on the bike might be a 10. How do I determine this? Thank you.

The chain has numbers and letters stamped on them. "HGX11" or whatever. Look those up.

Measure across the chain pins and consult with the manufacture's specs to match with a specific cog count intention. Andy

Chains are narrower the more sprockets they are designed to handle. A 10-speed chain will be narrower than the 9-speed chain, which will be narrower than an 8-speed chain, &etc. You can generally use a narrower chain on a wider cluster (e.g. a 10-speed chain on a 9-speed cluster) but not generally the other way around.

I thought this was going to be a math problem... like given Xmph in BBxx gear and Nrpm... what is the linear velocity of the chain in links per minute?