Timken48385-90012TDO Two-Row Tapered Roller Bearing Assembly – 5.5000 in Bore, 7.5000 in OD, 1.5000 in Cone Width, Class 2, Case-Carburized Steel

Product Description

What this part is

Timken 48385-90012 two-row tapered roller bearing assembly in the 48300 inch series. Cone bore 5.5000 in (139.70 mm), cup outside diameter 7.5000 in (190.50 mm), cone width 1.5000 in each. The assembly comprises two 48385 cones, one 48320-D double cup and one X1S-48385 cone spacer. Case carburized steel rings with stamped steel cages.

Decoding the designation

48385 is the cone number and 48320 the cup number. The D suffix on the cup identifies a one-piece double cup carrying two raceways, so one 48320-D seats both cones. The X1S prefix marks a cone spacer, ground to set the axial spacing between the two cones. The -90012 suffix is a Timken assembly number: it identifies a complete factory-matched build rather than a single component, and fixes which spacer and which cup go with the cones.

Quantity and configuration

Four pieces forming one complete bearing: two 48385 cones, one 48320-D double cup and one X1S-48385 cone spacer. The arrangement is TDO, tapered double outer — the two cones mounted back to back inside a single common cup.

What these specs mean in practice

A TDO assembly takes radial load and thrust in both directions, and the wide spread between the two roller paths gives it real moment capacity, so it holds shaft alignment against overhung loads. Because the assembly is supplied as a factory-matched build with its own spacer, the internal setting is fixed at manufacture, which removes the field adjustment a loose cone-and-cup pair would need. Class 2 is Timken’s standard tapered precision grade. Case carburized rings put a hard raceway over a tough core, favouring shock and heavy intermittent loading.

Mounting dimensions

Effective load centre location is -0.22 in, measured inboard of the reference face. The cone frontface backing diameter is 5.83 in, which is the minimum diameter a shaft shoulder or backing ring must present to support the cone rib. The cone backface to-clear radius is 0.14 in, so the shaft fillet must clear that dimension.

Fitting notes

The cones press onto a straight cylindrical shaft seat with the spacer between them, and the double cup fits a single housing bore. Cone spacing is set by the X1S-48385 spacer, so the two cones are drawn up solid against it. The cup is located axially between the housing shoulder and the end cap.

Interchange guidance

The 48385/48320DC set uses the same cones against a 48320DC cup, a different double-cup variant, making it a related size rather than a direct interchange. A single 48385 cone or a single 48320 cup covers component replacement within this assembly. Other -900xx numbers on the 48385 base, such as 48385-90040, are different factory builds with different spacers and internal settings.