SKF21308Spherical Roller Bearing – Tapered 1:12 Bore, 40 mm ID, 90 mm OD, 23 mm Width, Open, Pressed Steel CC Cage, CN Clearance

Product Description

What this part is

A double-row spherical roller bearing in the SKF 213 series with a tapered bore, 40 mm nominal bore, 90 mm outside diameter, 23 mm width. Two rows of barrel-profile rollers run on a common spherical outer raceway, so the assembly swivels inside the outer ring and absorbs up to 2° of shaft-to-housing misalignment while carrying heavy radial load and thrust in both axial directions.

Decoding the designation

21308 gives the ISO base: 213 dimension series, bore code 08 for a 40 mm nominal bore. CC is the SKF cage and internal design code, two pressed steel window cages with an inner ring guide ring between the roller rows. K is the 1:12 tapered bore. No clearance suffix follows, so internal clearance is normal, CN.

Tapered bore mounting

The 1:12 tapered bore mounts on a tapered adapter sleeve fitted over a plain cylindrical shaft, so the bearing can be positioned anywhere along an unstepped shaft. Supplied without adapter sleeve H308, KM locknut and MB lockwasher. Mounted radial clearance is set by drive-up distance on the sleeve taper rather than by the shaft tolerance.

What these specs mean in practice

Pressed steel cages keep rotating mass low and support a limiting speed of 7000 rpm; a machined brass cage in the same envelope raises load capacity and lowers the speed ceiling. The 213 series is the shallow cross-section spherical roller family, so at 40 mm bore it fits a 90 mm housing where the deeper 223 series needs more radial room for its higher rating.

Quantity and configuration

1 Pc. Open bearing, no seals and no shields. Bearing only, no snap ring.

Interchange guidance

FAG 21308-E1-K, NTN 21308EAKD1, NSK 21308EAKE4, Timken 21308K and Koyo 21308RHRK share the ISO envelope, the tapered bore and the series, and interchange on fit. Straight-bore 21308 is a related size rather than a substitute: it seats directly on a machined shaft step and takes no adapter sleeve. Operating range is −30 °C to 200 °C.