Road bike bearings

How to find the right bearing

Choose a bearing by its three dimensions, not by the bike brand or component three dimensions, engraved on the bearing ring or encoded in its part number. Inner diameter, outer diameter, width — in that order.

How to read a part number

• Codes such as 6902, 6802, 15267 or MR-2437 encode the dimensions directly: a 15267 measures 15 × 26 × 7 mm.
• The dimensions are always shown in brackets in the product titles in this section.
• Measure the removed bearing with vernier callipers rather than looking up the component’s part number: it’s quicker and more reliable.

ABEC 3 or ABEC 5

The ABEC measures manufacturing precision. Black Bearing B3 is ABEC 3, B5 is ABEC 5. On a bike, the difference in efficiency is small: the tolerances are already far tighter than a wheel requires. B5 makes sense for a high-end hub or racing wheel; B3 is more than adequate for a bottom bracket or derailleur pulley.

2RS, LLB and sealing

• 2RS means two rubber seals: that’s the standard sealing, and what you need on a bike.
• LLB from Enduro Bearings indicates low-friction seals, which are faster but offer less protection.
• For a bike ridden in the rain, sealing matters more than friction: a bearing that lets in water loses far more efficiency than a low-friction seal can gain.

Where they’re used

Front and rear hubs, bottom brackets, derailleur pulleys and freehub bodies. In each case, these are standard, commercially available bearings, so you can order the exact size rather than an often much more expensive branded kit.

Steel or ceramic

Ceramic bearings are lighter and have slightly less friction, but they don’t cope well with water or impacts and cost several times as much. They can be justified on a racing wheel; for everyday use, a good-quality steel bearing replaced more often remains cheaper and more reliable.

To find out more: How to choose road bike wheels

See also: Road bike hubs · Road bottom brackets · Road bike freehub bodies