⚙️ Ride Smooth, Ride Strong – The Bottom Bracket That Means Business
The Shimano UN300 English Bottom Bracket is a high-quality, sealed bottom bracket engineered for JIS square-taper cranksets. With a precise 68mm shell width and a hollow 113mm spindle, it offers enhanced chain stability through its innovative chain line stabilizer. Constructed from durable aluminum alloy, it ensures lightweight strength and long-lasting performance, making it the go-to choice for serious cyclists seeking reliability and smooth pedaling.
| Item Package Dimensions L x W x H | 7.2 x 5.59 x 1.73 inches |
| Package Weight | 0.29 Kilograms |
| Item Dimensions LxWxH | 5.63 x 2.03 x 1.91 inches |
| Item Weight | 0.01 Ounces |
| Brand Name | SHIMANO |
| Warranty Description | Limited Warranty |
| Model Name | Bottom Bracket - English, 68 X 113mm |
| Color | noir/argentà |
| Material | Alloy |
| Suggested Users | unisex |
| Number of Items | 1 |
| Manufacturer | Shimano |
| Part Number | EBBUN300B13X |
| Style | Bottom Bracket - English, 68 X 113mm |
| Included Components | Bottom Brackets |
| Size | 68mmx113mm |
| Sport Type | Cycling |
T**N
Good old standard square taper Shimano 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.
M**.
Works great. Shimano is the best!
Requires socket designed specifically for bottom bracket installation, sold separately.
M**
Perfect fit!
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.
J**K
Easy installation and smooth riding
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.
J**E
Perfect shimano quality
Installed nicely. Exact fit. Ultra high quality. 65g lighter than the stock BB that came on my older Specialized bike. Would buy again.
W**N
Best BB because of cartridge bearings
This BB has cartridge bearings which are much better than a BB assembled with ball bearings and races on the shaft and housing. This BB-UN300 is a direct replacement for a BB-UN73. Be sure to use anti-seize on aluminum and steel threads. The sleeve has thread-locker so placement of the anti-seize has to be carefully applied to prevent contamination of the thread-locker.
M**K
Cheap Fun
Smooth, zero slop, exact fit, easy to install!
M**J
Easy choice
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.
Trustpilot
1 month ago
2 days ago
