Best Bike Bottom Brackets of 2025

"I can't go wrong with genuine Shimano parts. I had a cheap plastic cup that lasted a year, but this all-metal version works awesome! I did encounter a problem with the tool fitting the notches, which could be an issue with the tool itself."

"I replaced the old, worn-out bearing set in my 1980's rigid frame Rockhopper, and this upgrade has made a noticeable difference. It fits well and seems well made. I'm looking forward to seeing how long it lasts."

"As an amateur bike mechanic, I did my research for a replacement BB for my 93 Bridgestone. The drive side fit perfectly, but the non-drive side didn't thread all the way in. I measured it at 68mm, which is what it's advertised as, but a couple of threads are still sticking out. Not a major problem, but I wanted to mention it. Overall, it's a well-made component at a great price."

"I decided to revive an old bike for winter training, and I was pleasantly surprised by how much LESS energy it took to ride with this new bottom bracket! The friction reduction claims were indeed true, and I could see it in my Zwift data. This part not only improved my efficiency but also gave the bike a more modern look. It's a great deal for the price!"

"After dealing with some annoying creaks in my gravel bike, I figured it was time to check the bottom bracket. I found this model to be inexpensive and a breeze to install. My pedaling is now smooth and silent again, which is fantastic! Just remember, you'll need a Hollowtech tool for the installation, which costs more than the BB itself."

"I recently replaced an older bottom bracket that was starting to grind, and the new one is a game changer. The smoothness and quality make for a noise-free spin. Just make sure you've got the right tools and torque it correctly for the best fit!"

"I found the installation to be easy for my 2021 Santa Cruz Tallboy D. The new bottom bracket is threaded, and it eliminated all squeaks from the old one. Just make sure to have the right tool for removal and installation, plus a torque wrench for proper tightening. For my Tallboy, I didn’t need any spacers."

"I installed this 73mm bottom bracket on my son's 2023 GT Aggressor Pro with the SRAM Eagle NX kit. It’s a fantastic upgrade!"

"This bottom bracket fit my XO1 cranks perfectly and came with various spacers like 2mm, 3mm, and 4.5mm. The installation was straightforward, although the tiny plastic pretensioner was a bit of a challenge for me."

"I found this product to be exactly as described. Installation was a breeze and it fit my bike perfectly."

"Installing this was straightforward. The larger bearing eliminated the noise from my crankset."

"It was a bit of work to take everything apart on my Nordictrack s22i, but now it's silent and works great!"

"I installed this bottom bracket with ease, and my 24mm hollow crank spins freely without any issues. After a few months, there's no sign of creaking or grinding, and the bearings are holding up well."

"Choosing Shimano is always a safe bet for me. This bottom bracket was simple to install, and the high-quality bearings have lasted through nearly 10K miles with no wear visible."

"For my Schwinn 564, this bottom bracket was just what I needed. After taking it for a test drive, I felt completely satisfied with my purchase!"

"I found that Shimano makes great quality products even at this price point. I installed this part into an older bike with a failing bottom bracket, and it made a huge difference. I believe this new bottom bracket will likely outlast the bike at this point. Great product at a great price!"

"As I was rebuilding my early 2000s Specialized Expedition hybrid commuter bike, I noticed that the original bottom bracket usually gets crunchy or noisy after 20 years. Instead of spending time cleaning and rebuilding, I decided to just buy a new replacement. After trying a few no-name substitutes, I returned to Shimano. The UN300 rides smooth and fits perfectly in my frame. My advice to novices is to use the right tools, take your time, and ensure everything is clean and well-greased during installation. Have an awesome day!"

"I had an upgrade on my old 1982 Schwinn Traveler bottom bracket, and it was just the right fit to replace the old ball bearing style. I’ve done this several times now, so I have the necessary tools, and I find these bottom brackets to be an affordable solution for restoring older steel bikes."

"I found this product to be of great quality right from the unboxing, and after installation, my bike rides wonderfully again. Definitely a recommended purchase!"

"I am thrilled with the noticeable smoothness and quietness of this upgrade over my old bottom bracket. Just make sure to order the correct cartridge length for a perfect fit."

"While this bottom bracket is exactly what I needed, I wish I had opted for a complete upgrade package instead. However, if you only need this part, it works perfectly as intended."

“I installed it without any issues. The fit was exact and I noticed it was 65g lighter than my stock bottom bracket. I would definitely buy it again.”

“Using this bottom bracket made my old bike feel brand new. Installation was a breeze and the bearings are so smooth. I’m confident it will last for many years.”

“I needed extra offset for my chainwheel, and of course, I chose Shimano. This replaced a sealed BB that lasted 25 years, so I’m expecting the same longevity from this one.”

"I wasn't ready to switch to hollow tech, so this was a great substitute for my ebike. The shaft was slightly wider, and I had to grind it down for the pedal sensor. I accidentally broke my original sensor trying to force it on. However, it works fantastically for all other standard bikes needing a replacement square taper bb."

"This unit was a perfect drop-in replacement, and it has completely restored my crank operation to be smooth with no freeplay at all. With the right maintenance, I believe this could last as long as my previous one did—around 30 years!"

"Being a Shimano product, I had high expectations, and it did not disappoint. It's not the lightest option available, but it's definitely lighter than the original bottom bracket."

"I absolutely love this bottom bracket! It was a perfect fit for my Mongoose Beast fat tire bike. Such a great product!"

"I replaced the original bottom bracket on my 21-year-old bike with this one. It fit perfectly and installed easily. It is sealed well to protect the bearings, and now I enjoy squeak-free rides. I'm very satisfied with my purchase!"

"Even though it’s listed as a used product, it arrived well-packaged and looks like new. In the short time I’ve used it, I haven’t encountered any issues. It’s definitely a good investment for the price."