[giosblue]

I'm looking to change my chainsett on my old Trek 5200. 9sp.
At the moment it's fitted with an Ultegra 6500 chainset with a Octalink BB.

I'm changing it to compact and I'm looking at these two options.


FSA SL-K ISIS 9 Speed Compact Road Crankset. If use this I will have to change the BB. to a ISIS. The problem with is FSA don't seem to make a BB the same width as the Shimano. According to Sheldon Brown the Shimano BB is 109.5, but FSA is 108 or 118. which one do I need.

The other option is SLK 10 speed with MegaExo BB cups. Would a 10 speed chainset work on a 9sp setup?

Any help much appreciated.

 

[JimP]

A 10 speed chainset works fine for me with a 9 speed setup. You may have to use a 10 speed chain though.

 

[jpz]

The 108 will work fine, different mfgr's, different lengths. The 118 is for their triple.

Jim

 

[AndrwSwitch]

Match the bottom bracket to the crank manufacturer's spec. They can be built for different spindle lengths.

As mentioned above, interchangeability between road 9- and 10-speed bits and pieces is pretty good.

If it were me, I'd choose whatever current Shimano crankset was priced around what I wanted to spend. But then, I'm a bit of a fanboy, and hold a grudge against FSA for perpetrating the Omega.