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. If your machine’s parts list specifies 14138A, order 14138A. If you are working from a housing bore and a shaft diameter with no parts list, either will physically fit. We are stating the distinction 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 mmCup outside diameter (D): 2.717 in / 69.01 mmAssembled width (T): 0.7813 in / 19.85 mmDynamic radial load rating C1 (1 × 106 rev): 54,600 NStatic radial load rating C0: 61,700 NDynamic C90 (90 × 106 rev): 14,200 NDynamic thrust Ca90: 9,260 NEffective centre (a): −4.3 mmMaterial: 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 you calculate the bearing loads. 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 you 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.

Note also that C1 and C90 are two different dynamic ratings, not a discrepancy: C1 is referenced to one million revolutions, C90 to ninety million. Compare C1 against a metric bearing’s ISO dynamic rating; use C90 in Timken’s own life formulae.

Quantity and configuration

One set in stock — one cone and one cup. Tapered roller bearings take thrust in one direction only, so most applications use two opposed, and replacing only one of a worn pair leaves the new bearing carrying the setting error of the old one. If yours is a pair, plan for two sets.

Fitting notes

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. Press only on ring faces — never through the rollers. Cones typically take an interference fit on the shaft; check Timken’s fitting-practice tables for your load class rather than assuming a fit.

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.