Timken28985W-3Taper Roller Bearing Single Cone 2-7/16″ ID Class 3 Precision

Product Description

What this part is

A Timken 28985W single cone — the inner race carrying the tapered rollers and cage — from the imperial 289xx single-cone series. Cone only. The matching cup is the Timken 28921.

Decoding the designation

28985 is the base cone number within Timken’s imperial 289xx block, which pairs against the 28921 cup. The W is Timken’s wide-variant letter on the cone. The trailing -3 is Timken precision Class 3, a tightened bore, runout and width tolerance grade above standard-class product.

Published specifications

Cone bore: 2.4375 in (61.91 mm)
Precision class: Timken Class 3
Rows: 1
Rolling elements: tapered rollers
Material: through-hardened bearing steel
Mating cup: Timken 28921

What these specs mean in practice

Tapered roller geometry takes combined radial and axial load in a single direction, the thrust share rising with raceway angle, which is why these run in opposed pairs on shafts that see load from both ends. Class 3 precision holds bore diameter and raceway runout tighter than standard class, giving more uniform roller loading and less shaft-induced eccentricity in gearbox, pinion and wheel-end positions.

Quantity and configuration

1 Pc. Single cone, set to clearance or preload on assembly against its cup.

Interchange guidance

28985W-3 and 28985W*3 are the same part written two ways. The plain 28985 is a related size in the same series and is a separate part number.