Timken25521BFlanged Tapered Roller Bearing Cup – 3.2700 in Outside Diameter, 0.75 in Width, 3.4220 in Flange Outside Diameter, Case-Carburized Steel

Product Description

What this part is:

Timken 25521B flanged tapered roller bearing cup, the outer ring of a single-row TSF tapered roller bearing. Part Number: 25521-B. Base Number: 25521-B. Series: 25500. Bearing type: Tapered roller bearing flanged cup. Number Of Rows: 1. Rolling Elements: Tapered Roller. Outside Diameter: 3.2700 in (83.058 mm). Overall Width: 0.75 in (19.050 mm). Total Width: 0.75 in (19.050 mm). Flange Outside Diameter: 3.4220 in (86.919 mm). Flange Width: 0.1563 in (3.970 mm). Number Of Flanges: 1. Design Units: Imperial. Precision Class: Not specified. Item weight: 0.60 kg (1.30 lb). Bearing Material: Case-carburized steel. Closure Type: Open. Unit Quantity: 1 Pc. GTIN: 0053893213880. Country of Origin: United States.

Decoding the designation:

25521 — the cup number in the Timken 25500 inch tapered roller bearing series.

B — flanged. The outer ring carries an integral flange at one end. Timken designates the flanged execution TSF, and the plain 25521 without the B is the unflanged cup, a separate part with its own number.

What these specs mean in practice:

Flanged cup only. The flange seats against the face of a through-bored housing, which locates the cup axially and squares the seal to the bore. Outside Diameter: 3.2700 in fixes the housing bore, Flange Outside Diameter: 3.4220 in sits proud of it, and Flange Width: 0.1563 in is the axial thickness of that shoulder.

e Factor: 0.33. K Factor: 1.74. Y Factor: 1.79. These are the Timken load factors that set the thrust-to-radial ratio at which axial load begins to govern the bearing life calculation, and the thrust multiplier used above it. A K factor of 1.74 marks a steep raceway angle, which carries a high proportion of thrust for a given radial load.

Geometry Factor (Cg): 0.0801, the geometry constant for the lubrication life adjustment factor a3l.

Bearing Material: Case-carburized steel — a tough core under a hard carburised raceway, which suits shock and heavy radial load.

Mounting data:

Maximum Housing Fillet Radius: 0.130 in (3.30 mm). Housing Backing Shoulder Diameter, Frontface (Da): 3.18 in (80.01 mm). These figures set the housing shoulder and corner relief the cup seats against. The flange takes the axial location that a machined housing shoulder would otherwise provide, which is what allows a straight through-bored housing.

Quantity and configuration:

Unit Quantity: 1 Pc. One flanged outer ring per listing.

Interchange guidance:

The B flange is a Timken TSF execution and carries a Timken-only part number. The industry interchange lists that cover plain inch cups run against the unflanged 25521, which is a different part with a different outer ring. No cross-reference is published here for that reason.

MPN Variants: 25521B, 25521-B, 25521 B. Industry Terms: flanged taper bearing cup, TSF flanged cup, flange outer race, flanged bearing race. Common Misspellings: Timkin 25521B, 2552B, 25512B, tappered roller bearing cup. Harmonization Code: 8482.20.00.