TimkenLL639249Tapered Roller Bearing Cone Only, 7.7500 in Bore x 0.9062 in Inner Ring Width, Inch Series – Mating Cup Not Included

Product Description

What this part is

This is the cone half of a single-row tapered roller bearing: the inner ring with its ground tapered raceway, the full complement of tapered rollers, and the cage that retains them, supplied as one non-separable assembly. It is the Timken LL639249 cone from the LL639200 inch series, with a 7.7500 in (196.850 mm) bore and a 0.9062 in (23.017 mm) inner ring width. The cone is the half that presses onto the shaft.

Product scope

Cone only. The matching cup is the Timken LL639210. A tapered roller bearing is two separately numbered halves: the cup (outer ring) presses into the housing, the cone (inner ring plus rollers plus cage) presses onto the shaft. They are sold apart because they wear at different rates and mount in different members, so a cone-only replacement is normal practice.

Decoding the designation

LL639249 — the Timken cone part number, LL marking a Timken inch (imperial) series.

639249 — the cone number, which selects the bore: 7.7500 in.

LL639210 — the mating cup number in the same series.

LL-639249-XX — a distributor notation, held here as a searchable cross-reference.

Precision Class: Not specified. No precision-class suffix is present on this cone, so it is the standard-class Timken product.

Published cone specifications

Cone bore (d): 7.7500 in / 196.850 mm.

Inner ring width (B): 0.9062 in / 23.017 mm.

Cone mass: 4.6 lb / 2.1 kg.

K factor: 1.4.

Effective centre location (a): 0.69 in / 17.5 mm.

Number of rows: 1.

Rolling elements: tapered rollers.

Design units: inch.

Series: LL639200.

Mating cup: Timken LL639210.

Unit Quantity: 1 Pc.

What these specs mean in practice

The K factor of 1.4 is the ratio of radial to thrust capability, set by the cup angle: a low K means a steeper angle and a bearing that carries proportionally more thrust for a given radial load. At 1.4 the LL639200 series sits toward the thrust-capable end of the tapered roller range, which suits shaft positions where a helical or bevel gear set throws significant axial load alongside the radial reaction: large gearbox shafts, pinion positions, heavy machine spindles.

A tapered roller bearing has no built-in internal clearance. The operating clearance or preload is created at assembly by how far the cone is drawn up against the cup, and that setting is the single largest determinant of service life in this bearing class.

Quantity and configuration

Priced and sold per single cone. Unit Quantity: 1 Pc. Single-row tapered roller bearings are normally mounted in opposed pairs, two bearings facing each other in a back-to-back or face-to-face arrangement, because one row takes thrust in one direction only. Each position also takes its own cup.

Mounting data

Maximum shaft fillet radius the cone corners clear: 0.06 in / 1.520 mm.

Shaft backing shoulder diameter, frontface (da): 7.99 in / 203 mm.

Shaft backing shoulder diameter, backface (db): 8.07 in / 205 mm.

Cage location relative to backface (Aa): 0.04 in / 1 mm.

Cage location relative to frontface (Ab): 0.14 in / 3.6 mm.

The cone is an interference fit on the shaft.

Interchange guidance

LL639249 is an industry-standard inch designation rather than a Timken-proprietary code, and cones to this number are produced by several manufacturers, so an LL639249 from another maker is dimensionally interchangeable. Searchable forms: LL639249, LL-639249, LL 639249, LL639249XX, LL-639249-XX, K-LL639249, L639249. Mating cup: LL639210, LL-639210, LL 639210. Complete assembly designations: LL639249/LL639210, LL639249-LL639210.