Shimano UN300 Square Taper Bottom Bracket

Works great. Spins around and around!

I love a square tapered bb just like the next rivendell riding retrogrouch, but we all can agree; they’re a total guessing game when it comes to which length you need. There’s only so much sheldon brown you can read before you just take an educated guess and bite the bullet and buy the length you think you need. Well enter the un300, they’re cheap and work great! Definitely punches above it’s weight class. The best part, if you get the wrong size, it’s not the end of the world and now you have a spare bb sitting around for the next time you try to 1x your 90s xtr crank and are wondering which length you need. I have several of these kicking around in various lengths for that specific purpose. Did I also mention they work great? They work well enough that I run them even if I have some fancy sugino 75s or the paul square tapered cranks. If you feel inclined to be fancy and get a phil wood or white industries, now you know which length to get and it only cost ~$15 instead of $100

Old school bottom bracket: English threaded, lots of options. I bought this to accommodate a Stronglight triple crankset to mount on a 1970’s Witcomb frame with a 68mm bb. It fits well but it’s a bit wide for proper chain line, so I’ll probably step down to the next to largest size.