Shimano BB-UN300 British Thread 73/113mm Bottom Bracket
- Sealed cartridge bearing
- Square tapered spindle fitting
- Durable, hard-wearing construction
The Shimano BB-UN300 British Thread 73/113mm Bottom Bracket is a reliable replacement bottom bracket for traditional square taper chainsets. It uses a sealed cartridge bearing assembly to help protect the bearings from dirt, mud, and water. Super-accurate bearings support smooth crank rotation, while the hard-wearing build gives dependable performance over regular use. Its narrow body also helps give clearance for cable routing under the bottom bracket.
Key Features and Benefits:
- Sealed cartridge bearing assembly: The cartridge design helps keep dirt, mud, and water away from the bearings. This reduces the need for maintenance and helps the bottom bracket keep running smoothly for longer.
- Super-accurate bearings: The bearings are made to support smooth and consistent rotation. This helps reduce roughness through the pedals and gives the chainset a more stable feel during use.
- Square tapered spindle fitting: The square taper interface suits traditional chainsets that use this proven fitting system. This makes it a practical choice for repairs, upgrades, or like-for-like replacements.
- Durable, hard-wearing construction: The bottom bracket is built for regular use and long service life. This helps maintain dependable support for the crankset over time.
- Fast and easy installation: The sealed cartridge unit fits without bearing adjustment. This makes fitting simpler and helps reduce setup time.
- Narrow body design: The compact body helps create clearance for cable routing under the bottom bracket. This supports a cleaner fit on frames where cable space is limited.
A smooth, reliable bottom bracket helps the drivetrain feel more direct and consistent. The BB-UN300 supports this with sealed bearings, a strong cartridge design, and simple fitment. It is well suited to bikes that use a British threaded bottom bracket shell and a square taper chainset.
Choose the Shimano BB-UN300 British Thread 73/113mm Bottom Bracket for a dependable replacement that is easy to fit, low maintenance, and built for steady long-term use.
Specification:
- Size - 73 - 113mm
- Bottom Bracket Type - BSA Threaded
- Width -73 mm
| Brand | Shimano |
| MPN | BBUN300C13 |
Our Payment Options
Online we currently accept payment from the methods listed above including a wide range of finance options. In store we also accept payment in the form of cash and gift vouchers.
Finance Options
In order to get the kit you want, when you need it, we offer a highly flexible range of finance options to help you get the best products on your bike now rather than at the end of the season when you've saved up the cash to make the purchase. There are even interest free options which effectively spread the cost without costing you any extra.
D.T.(Automotives) Limited T/A Tweeks Cycles is authorised and regulated by the Financial Conduct Authority and is the broker and not the lender. Our FCA registration number is 689896. D.T.(Automotives) Limited offers credit products from Secure Trust Bank PLC trading as V12 Retail Finance, Klarna and Clearpay. Credit is provided subject to affordability, age and status. Minimum spend applies. Not all products offered by Secure Trust Bank PLC are regulated by the Financial Conduct Authority. Klarna is unregulated credit. Clearpay is unregulated credit, use responsibly, T&Cs & late fees apply.
Our Finance Providers
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D.T.(Automotives)Limited trading as Tweeks Cycles offer interest free and interest-bearing credit on purchases £300 and over which is provided by V12 Retail Finance.
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We also offer Klarna, pay now, pay in 30 days or pay in 3 equal instalments.
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We also offer Clearpay pay in 4 instalments.
UK Mainland Delivery Prices
| Delivery Type | Cost | Estimated Delivery Time |
| Standard Delivery for orders under £49.99 | from £1.33 | 2-3 working days from day of despatch(Excludes weekends and Bank Holidays) |
| Standard Delivery for orders over £49.99 | Free | |
| Bike Delivery | Free | 3-5 working days from day of despatch *(Excludes weekends and Bank Holidays) |
| Express Delivery | from £1.68 | 1-2 working days from day of despatch(Excludes weekends and Bank Holidays) |
| Special Delivery | from £12.54 | For any next working day delivery order before 4.30pm Monday to Thursday. For any weekend delivery order before 4.30pm Friday |
* Bike Delivery Info
A bike has to go though a Pre Delivery Inspection (PDI Check) prior to despatch, ensuring the bike is thoroughly checked and set up prior to you receiving. This also means an express delivery service is unavailable. We strive to despatch bikes within 3-5 working days. Please note this may change over school holidays and the festive season (November/December). For more information on the process please visit our pre-build page.
For international shipping please visit our delivery page.
For information about returning an item please visit our returns page.