KoyoTapered Roller Bearing Cone and Cup, 1-3/8 in Bore x 2-23/32 in Outside Diameter, Inch Series, Single Row

Product Description

What this part is

A Koyo single-row tapered roller bearing supplied as its two halves together: the 14138A cone, which is the inner ring with its roller and cage assembly, and the mating cup, which is the outer race. Cone bore is 1-3/8 in and cup outside diameter is 2-23/32 in, so this is an inch-series bearing on the 141xx envelope. Tapered roller bearings carry heavy combined radial and axial load, with thrust taken in one direction through the roller taper.

Decoding the designation

In the inch tapered roller scheme the cone and the cup carry separate numbers and are quoted as a pair. 14138A is the cone; the A is a design revision within the 14138 cone family, not a size change. The matching cup number is 14276. Cone and cup numbers from different families are not mixed, because the raceway angle and the roller path are matched between the two halves at design.

What these specs mean in practice

The taper on a tapered roller bearing means every radial load produces an axial reaction, which is why the type is normally mounted as an opposed pair — back-to-back or face-to-face — so the two bearings react each other’s thrust. Setting is done at assembly: the pair is adjusted to a specified endplay or preload by shims, a locknut or a spacer, and that setting rather than the bearing itself determines running clearance and life. The 141xx envelope is a light-section inch series widely used on wheel hubs, idler shafts and light gearbox positions.

Quantity and configuration

1 Pc set: one 14138A cone and one mating cup. No spacers, no shims, no locknut and no seal.

Fitting notes

The cup is pressed into the housing bore square to its seat and the cone onto the shaft, with force applied only to the ring being fitted. Because the two halves separate, the rollers are kept with their own cone and the cup is not swapped between bearings. Setting endplay or preload happens after both halves are seated, with the assembly rotated under light load to seat the rollers against the cone rib.

Interchange guidance

Another maker’s 14138A cone with a 14276 cup fits the same position: Timken 14138A and Timken 14276, since the inch tapered roller numbering is common across brands. The 14125A is a related cone, not a substitution, because its bore is 1.2500 in. Likewise 14137A and 14130 are different cones on the same cup, and 14274 is a different cup on the same cone family — each changes bore or width.