Timken3521Tapered Roller Bearing Cup – 3.3970 in OD, 0.9375 in Width, Inch TS Series

Product Description

What this part is

Timken 3521 tapered roller bearing cup. This is the outer ring of a Timken TS single-row inch tapered roller bearing — the hardened, tapered outer raceway that the cone’s roller set runs against. Outside Diameter: 3.3970 in (86.284 mm). Overall Width: 0.9375 in (23.813 mm). Item Weight: 0.7 kg (1.6 lb). Rolling Elements: Tapered Roller. Number Of Rows: 1. Bearing Material: case-carburized alloy steel. Design Units: Imperial. Base Number: 3521.

Decoding the designation

3521 — a cup number in Timken’s inch tapered roller series. The number identifies the outer ring on its own; the cone that runs inside it carries a separate number.

No precision suffix is present on this part. Precision Class: Not specified.

What these specs mean in practice

e Factor: 0.31. The e factor is the ratio of thrust load to radial load above which the thrust component begins to govern the equivalent load calculation for the mounted bearing. A 0.31 value marks this as a shallow-angle cup, weighted toward radial duty, with thrust taken as the secondary load.

Geometry Factor (Cg): 0.0808. This is the geometry constant Timken uses in the lubrication life adjustment factor a3l.

Mounting data

Maximum Housing Fillet Radius: 0.130 in (3.30 mm) — the largest fillet the housing shoulder may carry and still be cleared by the cup corner. Housing Backing Shoulder Diameter, frontface (Da): 3.18 in. Housing Backing Shoulder Diameter, backface (Db): 2.95 in. The cup is a press fit in the housing bore and seats against the housing shoulder; a TS pair is mounted in opposition and set to the required end play or preload through the cone position.

Quantity and configuration

Unit Quantity: 1 Pc. Cup only — the outer ring. A cup has no bore, no cage and no seal; those belong to the cone.

Interchange guidance

The 3521 is an inch tapered roller cup on the Timken dimensional standard, so a same-number cup from another inch-series maker matches the envelope and the raceway angle. Cup and cone raceways are matched between the two halves of a bearing, so a 3521 runs against its own published cone.