Last Sunday I was doing some interval training on my turbo trainer when I noticed a nasty mechanical clicking sound from somewhere around my bottom bracket. It sounded just like a cracked bearing, so I borrowed a crank extractor, took the cranks off, only to find that my BB bearings were absolutely smooth, no sign of a problem at all. Mystified, I put the cranks back on, and while I was doing that, noticed that the left crank was cracked from centre hole to the outside of the spider, all the way through. I’m very glad I wasn’t riding when it finally went! XT stuff isn’t meant to do this!
It turns out that it’s more or less the same price to have a new combined BB and chainset rather than just replacing the old taper-fit chainset, and it should be lighter, stiffer and stronger into the bargain. So Chain Reaction delivered me a nice Deore LX Hollowtech II chainset, and Brockley Cycle Team fitted it for me today, along with some good advice.
(Added a picture of it 22/9/2008).