Shimano UN300 sealed cartridge bottom bracket with square tapered spindle, BS 73 shell and 118mm axle, for riders running traditional chainsets.
The UN300 is a sealed cartridge bottom bracket with a square tapered spindle, built for traditional chainsets. The two numbers that decide it for you are the BS 73 shell figure and the 118mm axle, so check both against what you are replacing before you commit. The bearings are accurate and smooth running, and the cartridge is sealed as a maintenance-free unit that keeps dirt, mud and water away from the bearings for a long service life.
Installation is quick with no adjustment needed once it is in, and the narrow body leaves clearance for cable routing under the bottom bracket shell. It suits anyone whose old square taper unit has gone rough or notchy. We have it on the shelf in Kennington for free click and collect, and our mechanics can fit it for you the same day.
Free same-day Click & Collect. Order online and collect from our London workshop, usually ready within a couple of hours. We will email you the moment it is ready.
Home delivery. Dispatched the same working day on orders placed before 3pm. Standard UK delivery is £2.99, free on orders over £75, tracked, and typically arrives in 2 to 3 working days.
Fitting while you wait. Buying a part you would rather not fit yourself? Our mechanics can fit most parts on the spot. Just ask when you collect.
30-day returns. Changed your mind? Return any unused item in its original packaging within 30 days for a full refund.
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