Bottom Bracket 68mm x 118mm Specialized Allez Sport

Well, I guess my bike finally got to the point where it needed some serious maintenance. The bike is a Specialized Allez Sport from I guess about 2001. The bottom bracket was making a clicking sound on each revolution when I bought it from my friend. Once my 5'11" 240lb frame started abusing it daily for 26 miles, it finally started making a grinding noise and needed to be replaced.

One of the biggest problems was finding a square taper bottom bracket. It seems that they switched to Octalink a while ago, and now they are all about the two piece crank with external bearings. I don't actually know what the real benefit is to that, except possibly more strength from the BB.

Anyway, changing the bracket was really easy. I'd read Sheldon Brown's Articles on Bottom Brackets first because it is critically important to figure out what your bottom bracket's size is. It will affect your shifting and pedaling performance if you don't.

Next, take the cranks off, use a crank puller, don't try to remove it any other way, I did and it wasn't fun. Then use the bottom bracket tool to take it out. I'd clean up inside your frame while you've got it out. Finally, just put it back in the way it came out. Always unscrew the plastic side first. Sometimes it is a cheap chrome, usually it will be on the opposite side of the crank's cogs.

Anyway, if you have an old Allez from 2001, the bottom bracket you need is going to be 68mm x 118mm. The other thing to look at is the type. Probably the best you will be able to find will be the Shimano UN-73 Square Taper Bottom Bracket. I ended up going with the UN-52 because it was the only one I could find. Actually it was an upgrade from whatever was already in there. My bike is a fair amount lighter, and having a new bottom bracket is like riding on butter.