Shimano BB-UN300 bottom bracket
USA orders totaling $100 or more receive free shipping.
This applies to standard shipping in the contiguous 48 states and military APO/FPO addresses only. Oversized items are excluded from the free shipping offer.
All other shipping charges are shown in the cart before checkout. Free shipping does not apply to orders shipping outside the USA.
For complete information, please see our Shipping page.
If you are a local customer choosing the Store Pickup option at checkout,
please wait to receive an email saying your order is ready before coming to pick it up.
Local orders may not be ready the same day they are placed.
⚠️ IMPORTANT NOTICE: Effective 10/14/22, the option for local pickup is unavailable because we are in the process of moving to a new location. Until our new retail store opens in early 2023, all orders placed online will be shipped.
Returns for eligible products are accepted within 30 days of the purchase date. Some exclusions apply.
For complete information, please see our Returns page.
The UN300 is a JIS square taper bottom bracket featuring sealed cartridge bearings, steel cups and a hollow cro-mo steel spindle.
Available in 107mm & 110mm lengths.
• 68mm English-threaded (BSA)
• JIS square-taper
• spindle length: 107mm, 110mm
• crank arm bolts not included
• requires Park Tool BBT-22 for installation & removal