Crank Upgrade

Ok, this wasn't strictly necessary, but my friend MF found a great deal on nice modern (silver) cranks, my quick research showed they'd save significant weight over what I had, and my old blue ones were frankly on the ugly side. Here's the finished pic:

One surprise was I found my BB shell was damaged, perhaps from when I broke my chain a few months ago. (This is the part of the bike frame which holds the bearings the pedals spin around.) This didn't matter for the old crank set, but the new-fangled type press in from the outside and are sensitive to any imperfections. I thought about putting the whole frame on the milling machine and trying to face it myself, but decided to bring it to a bike shop. CycleLoft did a good job and charged me less than quoted over the phone. The more I read about troubles with these new BB designs, the happier I am that I did this. Here's the BB face before and after facing:

The other surprise is the weight difference is only 60g. "On paper" it looked like it would be bigger, but I found a lot of the difference is in the big chainring, which I don't use. The pictures below show the parts of each crankset that I did use, and is apples-to-apples.

A sub-part of the weight surprise is that the left crank is actually heavier in the new XT than the old LX crank, including the fasteners for the respective crank. XT is 227g, while old LX is 209. (XT is a higher-level line of components, so should typically weigh less than LX, and in general newer parts should be a little better than old ones.) The left crank does have a bigger job in the new design than the old one had: it maintains the preload on the BB bearings, so its joint slides for adjustment and then tightens in place. (The old design has the preload factory-adjusted in a single-piece BB component, and the crank arms just bolt on.)

In the end, it looks great and should work well. I am left with a bit of skepticism about the preload mechanism, though. The left crank is supposed to be periodically re-tightened, which makes it more fussy than the old design. I think I would hesitate to put this on my road bike, but the older designs are going out of production. Along the way I found I have a problem with the old-design (Octalink) left crank on Slushbike, though I think it will last a while. This has me a bit soured on the Shimano BBs at the moment. I've admired the Campagnolo "Ultra-torque" design, and at the moment it looks like the best to me. But Campagnolo isn't making triple cranks these days, so I can't use one. (Instead they're working on electronic shifting - ugh!)