FAG20311KSingle Row Barrel Roller Bearing – 55 mm ID, 120 mm OD, 29 mm Width, 1:12 Taper Bore, Brass Cage, Open, Normal Clearance

Product Description

What this part is

A FAG single-row barrel roller bearing, 55 mm bore by 120 mm outside diameter by 29 mm wide, with a 1:12 tapered bore and a machined brass cage. Barrel roller bearings run one row of short, barrel-profile rollers on a concave outer raceway. That geometry gives the bearing a high radial capacity for its section and the ability to accommodate shaft misalignment, and it is a purely radial bearing.

Decoding the designation

20311K reads as follows. 203 is the FAG single-row barrel roller series. The final two digits, 11, are the ISO bore code, and the bore is that figure times five, giving 55 mm. K is the 1:12 tapered bore.

What these specs mean in practice

The barrel roller profile and the concave outer raceway let the inner ring tilt relative to the outer without edge loading the rollers, so the bearing absorbs shaft deflection and housing misalignment. Load capacity is radial. Axial location of the shaft is provided by another bearing in the arrangement. The machined brass cage guides the rollers positively and tolerates high temperature and shock better than a pressed cage, which is what makes it the standard cage for this series.

Quantity and configuration

1 Pc. Single row, open both faces, no seals or shields, normal internal clearance. Supplied without the H311 adapter sleeve, KM11 locknut and MB11 lockwasher.

Fitting notes

The 1:12 tapered bore seats on an H311 adapter sleeve, which puts the bearing on a 50 mm straight shaft. Drive-up on the sleeve sets the internal clearance, so the reduction in radial clearance during mounting is the measurement that matters rather than the axial travel. A tapered bore can also be fitted directly to a matching 1:12 tapered shaft journal, in which case no sleeve is used.

Interchange guidance

The same-spec equivalent is SKF 20311 K, with Timken and NSK 20311K to the same envelope and taper. A 20311 with no K is the straight-bore version of the same bearing and is a related size rather than an interchange, since it mounts differently. A 21311 or 22311 at a similar envelope is a double-row spherical roller bearing, a different bearing that takes thrust in both directions.