Timken53178-90036Tapered Roller Bearing Matched Assembly 1-3/4 in Bore x 3-3/4 in OD

Product Description

What this part is

A Timken 53178-90036 tapered roller bearing matched assembly, 1-3/4 in bore and 3-3/4 in outside diameter. The assembly is built on the 53178 cone and the 53375 cup.

Decoding the designation

Timken numbers ending in -90xxx are assembly numbers rather than component numbers: they identify a complete bearing built and set at the factory, with the component numbers listed separately. Here 53178 is the cone, fixing the bore, the cone width and the raceway angle, and 53375 is the cup, fixing the outside diameter and the matching outer raceway.

What a matched assembly buys

In a matched assembly the pieces are selected together and the internal geometry is controlled as a set, so the bearing arrives with its setting already established rather than needing to be shimmed in on the bench. That removes the largest source of scatter in tapered roller bearing life, which is a setting made by feel: too much end play loads too few rollers, too much preload runs the bearing hot. It also means the pieces are kept together as a unit through service.

What these specs mean in practice

Tapered roller geometry carries high radial load with substantial thrust through the raceway angle. The 1-3/4 in bore with a 3-3/4 in outside diameter is general industrial section — gearbox shafts, wheel ends, conveyor and agricultural drives.

Fitting notes

Cup and cone are pressed home separately, each with force on its own back face and never through the rollers. The pieces of a matched assembly stay together as supplied, since the setting belongs to that combination.

Interchange guidance

The assembly interchanges as a unit by the -90036 number. The components interchange individually by their own numbers: a cone marked 53178 and a cup marked 53375 from another tapered roller bearing maker are the same specification, though bought loose they arrive unset. A 53178 against a cup other than the 53375 is a different bearing, since the raceway angle is matched between the halves.