Timken14138A-90104Imperial Tapered Roller Bearing Cone & Cup Set, 1-3/8″ Bore x 2.717″ OD x 0.7813″ Wide

Product Description

What this part is

A Timken single-row tapered roller bearing supplied as a factory cone-and-cup set: cone 14138A running in cup 14276. The cone is the inner ring complete with its rollers and cage; the cup is the separate outer ring. Because the two halves are separable, one can be pressed onto the shaft and the other into the housing independently, which is why tapered roller bearings suit split housings, gearboxes and wheel ends where a one-piece bearing cannot be fitted.

Decoding the designation

14138A: the cone, current design revision.

14276: the mating cup at this envelope.

-90104: a Timken assembly number. The 9xxxx range designates a factory-supplied set rather than a single loose ring, which is what makes this a cone-and-cup listing.

X2S-14137: a Timken component prefix seen on matched-assembly bills of material for this family. It appears on this record as a cross-reference and is retained here because it is a real number a buyer may be searching.

14137A or 14138A — why the cone number still matters:
Both cones fit the same 14276 cup and both give the same 1.375 in bore, 2.717 in outside diameter and 0.7813 in assembled width. That makes them dimensionally interchangeable at the housing and the shaft. What differs is the cone geometry itself, and Timken lists them as separate part numbers rather than as suffixes of one another. Where a machine parts list specifies 14138A, 14138A is the part; working from a housing bore and a shaft diameter alone, either will physically fit. The distinction is stated plainly rather than presenting the two as identical, because a maintenance engineer replacing one bearing in an opposed pair wants the same cone as its partner.

Published ratings and mounting data

Bore (d): 1.375 in / 34.93 mm.

Cup outside diameter (D): 2.717 in / 69.01 mm.

Assembled width (T): 0.7813 in / 19.85 mm.

Dynamic radial load rating C1 (1 x 10^6 rev): 54,600 N.

Static radial load rating C0: 61,700 N.

Dynamic C90 (90 x 10^6 rev): 14,200 N.

Dynamic thrust Ca90: 9,260 N.

Effective centre (a): −4.3 mm.

Material: through-hardened bearing steel.

What these specs mean in practice

The negative effective centre of −4.3 mm is the specification most often ignored and it changes how the bearing loads are calculated. The effective centre is where the resultant load line crosses the shaft axis, and on a tapered roller bearing it sits outside the physical bearing rather than at its middle. A negative value means it falls on the outboard side of the bearing face. Working out the reaction loads from the shaft centreline instead of the effective centre gives the wrong span, the wrong load split between the two bearings, and a life prediction that flatters one and understates the other. On a short, heavily loaded shaft the error is significant.

C1 and C90 are two different dynamic ratings, not a discrepancy: C1 is referenced to one million revolutions, C90 to ninety million. C1 is the figure comparable with a metric bearing’s ISO dynamic rating; C90 is the figure used in Timken’s own life formulae.

Quantity and configuration

One set — one cone and one cup. Tapered roller bearings take thrust in one direction only, so most applications use two opposed, and a worn pair is normally replaced as a pair because a new bearing otherwise carries the setting error of the old one.

Mounting data

Endplay or preload is established at assembly by the shoulder-to-shoulder distance in the housing, not by the bearing width, so the assembled 0.7813 in figure is a reference dimension rather than a setting.

Cone backface “to clear” radius: 0.03 in. Cone frontface backing diameter: 1.57 in. Cone width: 0.7710 in. Cage-to-cone frontface clearance: 0.05 in. Cage-to-cone backface clearance: 0.08 in.

Cones in this family normally take an interference fit on the shaft; Timken’s fitting-practice tables give the fit for each load class.

Interchange guidance

Search forms include 14138A-90104, 14138A/14276, 14138A 14276, 14138A-14276, 14138A90104, plus the loose components 14138A and 14276 and the assembly prefix X2S-14137. The 14137A cone is the same-envelope alternative. The 14100 inch series is an established industry standard, so equivalents at this envelope are also catalogued by NTN, Koyo, NSK and SKF under the same numbers.