I broke an aluminum left crank arm on a 1000KM brevet last weekend. Unfortunately, I had to abandon the brevet because I was in an area that had no services whatsoever. I was over halfway done and doing well, just really sucked bad, the whole deal. Usually it's the engine that I have problems with, but this time the bike let me down. The first clue was that the crank bolt kept backing out, I would tighten it back down but then it would be loose again in a few miles. Eventually, the bolt bottomed out and I could not pedal anymore.

I was using Sugino XD600 8 speed MTB cranks 46-36-26, with a Shimano BB-UN55 square taper bottom bracket. I weighed 260-265ish at the time of the ride and had about 20 lbs of gear in the back in a Carradice bag. Was standing in the climbs pretty often, but that's never caused a problem before.

So what cranks do other folks use for usage on the more extreme side? Interested to see what other Clydesdales are using.