MTB Frame Bearings

How to choose your MTB frame bearings

Full-suspension pivots do not rotate: they oscillate through a few degrees, under heavy loads, and often in water and mud. It is the harshest treatment a bearing can face on a bike, requiring a different bearing type than a hub.

Why choose a MAX bearing

• A MAX, known as full complement, has no cage: the freed space allows for more balls.
• For the same dimensions, it can therefore withstand a significantly higher radial load than a standard bearing.
• In return, it spins less freely at high speeds — which makes no difference on a pivot that only oscillates a few degrees.
• This is why it is essential for frame pivots, where a standard hub bearing would develop play in just one season.

Reading the dimensions

The logic is the same as for all bearings: the numbers encode the inner diameter, outer diameter and thickness. 6800 for 10 x 19 x 5 mm, 6901 for 12 x 24 x 6 mm, 6802 for 15 x 24 x 5 mm, 6903 for 17 x 30 x 7 mm. Check the reference engraved on the removed bearing, or consult the frame documentation — many manufacturers publish the full list of bearings for their kinematics.

When to replace them

• A noticeable play by pushing the rear wheel sideways, with the bike raised and the shock unbolted.
• Some creaking noises under hard pedalling or out of the saddle, which is often mistakenly blamed on the bottom bracket.
• A suspension that no longer compresses smoothly when pushing down on the saddle, a sign of seized pivots.
• As a rule, after a full winter on a bike ridden in the mud, or once a year under heavy use.

During reassembly

• Replace all bearings on the same pivot at the same time: replacing just one bearing wears out its partner in a matter of weeks.
• Use a bearing puller and press, never a punch and hammer: the slightest distortion of the housing ruins the new bearing.
• Grease the bearing seats before insertion to minimise corrosion between alloy and steel.
• Respect the tightening torques for the pivot axles specified by the manufacturer: an overtightened axle preloads the bearing and ruins it prematurely.

To find out more: MTB rear suspension kinematics

See also: MTB bearings · MTB rear shocks · MTB shock bushings and spacers