Parts of a Bearing – 12 Labeled, Ball and Tapered Roller

All 12 parts on the diagram

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Ball bearing, face-on 6

Outer ring Sits in the housing; the balls roll round its inside.
Inner ring Fits on the shaft and usually turns with it.
Balls The rolling elements: they roll instead of sliding.
Cage Keeps the balls or rollers evenly spaced so they never touch.
Bore The hole the shaft goes through.
Shield Closes the gap to keep grease in and dirt out. Rubber ones are seals.

Ball bearing, cut through 3

Raceway The groove in each ring that the balls run in.
Outside diameter Measured across the outer ring: the size of the housing it fits.
Width Measured along the shaft, face to face.

Tapered roller bearing 3

Cup The outer ring of a tapered roller bearing.
Cone The inner ring of a tapered roller bearing, with its ribs.
Tapered rollers Rollers shaped like cut cones, so the bearing takes end thrust too.

How this list was compiled: Read 2026-09-23. (1) Wikipedia, Rolling-element bearing, https://en.wikipedia.org/wiki/Rolling-element_bearing: rolling elements between two grooved rings called races; outer and inner track, a central bore and a retainer that keeps the rolling elements apart; bore diameter; outside diameter; sealed bearings. (2) Wikipedia, Ball bearing, https://en.wikipedia.org/wiki/Ball_bearing: inner and outer races, each with a groove for the balls; the cage; outer diameter and width. (3) Wikipedia, Tapered roller bearing, https://en.wikipedia.org/wiki/Tapered_roller_bearing: separable into a cone assembly (inner ring, rollers and cage) and a cup; conical raceways whose lines meet on the axis. (4) A bearing maker's engineering manual (PDF), https://www.timken.com/resources/timken-engineering-manual/: bore, outside diameter and width as the size of a bearing; inner and outer rings; raceways; cages; shields and seals on ball bearings; cup and cone of tapered roller bearings. Licence: own work

The drawing: Drawn for this site by script, 2026-09-23. Licence: own work

How it works

A rolling bearing puts balls or rollers between two rings, so a shaft turns on rolling parts instead of sliding. A cage keeps them apart, and the bore takes the shaft.

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Ball bearing

The inner ring fits on the shaft and the outer ring in its housing. Each ring has a groove, the raceway, that the balls run in. A shield or seal closes the gap between the rings; here one covers a quarter so the balls still show.

Tapered roller bearing

Its outer ring is the cup; its inner ring, with the rollers and cage, is the cone. The raceways and rollers are cones whose lines meet at one point on the axis, so the bearing carries end thrust as well as load across the shaft.

Questions and answers

What are the parts of a ball bearing?

An outer ring, an inner ring, the balls between them and a cage that keeps the balls apart. Each ring has a raceway groove, and many bearings add a shield or a seal on each side.

Is a race the same as a ring?

Often, yes: many people call the rings the inner and outer races. Strictly, the raceway is the groove in each ring that the balls or rollers run in.

What is the difference between a cup and a cone?

Both belong to a tapered roller bearing. The cup is the outer ring. The cone is the inner ring, and it holds the rollers and cage as one piece, so the bearing comes apart in two.

How is a bearing measured?

By its bore (the hole for the shaft), its outside diameter and its width. The first two are measured across the bearing, the width from one face to the other.