SHIMANO UN300 English Bottom Bracket

Made a "new" bike using an old frame. I'm glad there's still some parts that Shimanos continues to make , like bottom brackets for square taper standards.The Shimano UN-300 bottom bracket is 68/73 width, was easy to install, and smooth bearings. Will last for years and years.

The BB on my 1996 Giant mountain bike wasn't bad but I felt like doing some maintenance and upgrades. After following some Youtube videos, I felt confident enough to change the old one with this new one. If you don't have one, you'll need a crank arm puller which isn't that expensive but necessary to have. Luckily, none of the threads were frozen so removal was rather easy. After cleaning out the BB shell, reassembly was straightforward and easy. The whole project took about 45 minutes. When everything was buttoned up, I took the bike for a test ride. I was impressed by how smoothly the crank turned and the bike seemed to have a new life. You'll need some grease for the threads plus a 20-tooth spline to unscrew/re-tighten the cups.

Went in with no fuss and is silent as can be. No telling on longevity, but the previous one lasted twenty years of hard, off-road use and was still technically function, just squeaky.Was a fun job, first time doing it myself. Much easier than I imagined and was great to save the $$ vs a shop visit.

I have been slowly upgrading/replacing parts on an old Nishiki mountain bike. The latest part to die was the bottom bracket. This one was super easy to install. All in all it took me about 15 minutes to remove the old one and install this one. Went on my first ride after and it was super smooth.

Installed nicely. Exact fit. Ultra high quality. 65g lighter than the stock BB that came on my older Specialized bike. Would buy again.

I had to use a Shimano crankset regarding I couldn't find my Sugino original chain rings. The Q Factor of the Shimano was two inches (in total) wider than my Sugino, and it caused much higher forces on the bottom bracket bearings.I returned the right original crankset, and it will work much longer this way.

I needed a BB with a little more offset on the chainwheel side for a bike I was rebuilding, and of course you can’t go wrong with a Shimano. This replaced a sealed Shimano BB that had been on my bike for 25 years and was still as good as new; I expect this one to do as well.

I have not used it yet, but I plan to put it on a bicycle. That's what it's for.