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.