Timken3426Imperial Tapered Roller Bearing Cup / Outer Race, 3.1230 in / 79.324 mm OD x 0.9375 in Wide, Plain Single Cup – 1 Pc

Product Description

What this part is

This is an imperial tapered roller bearing cup — the outer race only. There are no rollers, no cage and no inner ring. The mating cone (inner ring with rollers) is a separate part number and is not included in this listing.

Decoding the designation

3426 is a Timken imperial single cup in the 34xx family, a plain unflanged cup of Timken type TS — not a flanged cup and not a double cup. It is published as the mating outer race for a broad set of cones: 3474, 3476, 3477, 3478, 3479, 3480, 3482, 3483 and 3490. Cone 3474 gives a 1.1875 in / 30.163 mm shaft bore; cone 3490 gives 1.5000 in / 38.1 mm.

Correcting the source data

Earlier copy on this listing gave the width as 1-3/4 in. The published width of a 3426 cup is 0.9375 in / 23.813 mm. The 3.1230 in outside diameter in the original copy is correct. Machine your housing depth to 0.9375 in.

Published dimensions and mounting data

Cup outside diameter (D): 3.1230 in / 79.324 mm
Cup width (C): 0.9375 in / 23.813 mm
Housing backing shoulder diameter (Da): 2.94 in / 74.68 mm
Housing backing shoulder diameter (Db): 2.64 in / 67.06 mm
Maximum housing fillet radius cleared: 0.130 in / 3.30 mm
e factor: 0.37 · Y factor: 1.64 · geometry factor Cg: 0.0781
Weight: 1.4 lb / 0.7 kg

Load ratings are published against the cone, because a rating only exists for a cone-and-cup pair. None is quoted here, since an assembly rating on a cup-only listing would mislead.

What these specs mean in practice

The value of a cup that mates nine different cones is flexibility: the same housing bore and the same seat depth will carry shaft sizes from 1.1875 in up to 1.5000 in simply by changing the cone. That is why the 34xx family is common in equipment built in several shaft variants off one casting. The e value of 0.37 with Y 1.64 puts the pairing in the middle of the range — balanced radial and thrust duty rather than specialised either way.

Quantity and configuration

This listing ships 1 Pc — one cup. No cone, no rollers, no seal, no spacer.

Fitting notes

Press the cup into the housing from its back face with a flat driver that spans the full ring rim; never strike the raceway lip. Seat it hard against the housing shoulder before setting the bearing — a cup short of its shoulder reads as end play that no nut adjustment will properly remove. Keep the housing fillet within 0.130 in. This cup carries light storage surface rust; clean and inspect the raceway before installation, since rust in the raceway track, unlike rust on the outer diameter, does affect service life.

Interchange guidance

3426 is a standardised imperial cup number, so 3426 cups from Timken, Bower/BCA, Koyo, NTN and Federal-Mogul share the same envelope and interchange. 3420 is a related size, not an equivalent — it is 3.1250 in in outside diameter against 3.1230 in here, and although both are listed as mates for cone 3490 they are separate catalogue cups with different seat requirements. Order by number, not by measured diameter.