Bearing Selection

We've written this guide to help you select the right bearing for your application.

6804 Bearing

Bearing Codes

The bearing on the right has 6804RS moulded into the seal.  6804 is the bearing size, which is usually listed in catalogues as “Inside Diameter x Outside Diameter x Width”. This bearing is 20 mm x 32 mm x 7 mm. The full name for a cartridge bearing like this is "Deep Groove Ball Bearing".

Seal Codes

•  No suffix = no seals; i.e. the balls are exposed
•  RS/2RS/LLU/LLB etc = rubber contact seals
•  Z/ZZ = steel shields, not sealed

For a bicycle application, rubber seals are usually the best choice.  Some grease port pivots require bearings with no seals or steel shields.  Shockcraft sells these too.

ABEC Grades

An ABEC code indicates the grade the bearing is made to.  Bearings with higher ABEC grade numbers have tighter manufacturing tolerances for running at higher speeds and a higher cost.  ABEC1 is the lowest grade, ABEC9 the highest.  Shockcraft offers wheel & bottom bracket bearings in ABEC 3 and ABEC 5.

Full Complement Bearings

BearingsA normal deep groove bearing (shown at immediate left) contains balls with a cage to hold them apart.  A Full Complement (MAX) bearing (shown at far left) is packed full of balls (without a cage).  This arrangement gives MAX bearings more contact area, making them last longer in situations of high load and short rotation (such as in suspension pivots).  In applications that see continuous rotation (such as wheels and bottom brackets) MAX bearings aren't a good choice.  The lack of a cage results in the bearings rubbing on each other, causing premature wear and failure.  Raceface's X-type bottom bracket is a good example of this.  We replace a lot of bearings in these types of bottom brackets with Enduro caged bearings.

 

 

Ceramic Hybrid Bearings

These have conventional steel outer races but with ceramic balls inside.  The harder ceramic balls roll a little easier, weigh a little less and the whole bearing has been designed to minimise rolling friction.  These are ideal bearings for those seeking higher performance and lighter weight.

Written by:
Dougal
Shockcraft

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