Timken389AW/382Single-Row Tapered Roller Bearing, Cone and Cup, 2-1/8 in Bore x 3-7/8 in OD

Product Description

What this part is

A Timken 389AW/382 single-row tapered roller bearing, supplied as both halves together: the 389AW cone with its rollers and cage, and the 382 cup. Bore 2-1/8 in, outside diameter 3-7/8 in.

Quantity and configuration

1 Set — one cone and one matching cup, which is one complete bearing.

Decoding the designation

Timken writes a tapered roller bearing as cone number over cup number. 389A is the cone and fixes the bore, the cone width and the raceway angle, with W a Timken variant marking on that cone. 382 is the cup and fixes the outside diameter and the matching outer raceway. Either half can be ordered on its own by its own number.

What these specs mean in practice

A 2-1/8 in bore inside a 3-7/8 in outside diameter is a comparatively slim section for the shaft size, which keeps the bearing compact and the outer envelope small where housing space is limited. Tapered roller geometry carries high radial load together with substantial thrust in one direction through the raceway angle, so the type is fitted in pairs facing opposite ways to locate the shaft both ways. The 380 block is one of the widely used general-industrial imperial taper families.

Fitting notes

Cup and cone are pressed home separately, each with force on its own back face and never through the rollers. Once both are seated, the bearing is set by moving one race axially against the other to establish the intended end play or preload, since a tapered roller bearing carries no built-in clearance.

Interchange guidance

389A and 382 are industry-standard numbers, so a cone marked 389A and a cup marked 382 from another tapered roller bearing maker interchange as the same specification. The 382A and 382S are different cups in the same family with their own widths, so they are related sizes rather than substitutions. A plain 389 without the A is an earlier design of the cone and is likewise a related part.