Timken377-3Imperial Tapered Roller Bearing Cone, 2.0625 in / 52.388 mm Bore, Class 3 Precision, Mates Cup 372A – 1 Pc

Product Description

What this part is

This is an imperial single-row tapered roller bearing cone — the inner ring with its tapered rollers and cage. It is one half of a tapered roller bearing. The mating cup (outer race) is a separate part number and is not included in this listing.

Decoding the designation

377 is the Timken imperial cone number and its matching cup is 372A (372 is also listed), so a complete single-row bearing is a 377 cone plus a 372A cup. The trailing -3 (also written *3 or #3) is Timken’s precision Class 3. Timken tapered roller classes run Class 4 (standard commercial), then Class 3, Class 0 and Class 00 in increasing precision, so this cone is held to tighter bore and running-accuracy tolerances than the standard part.

Published dimensions

Cone bore (d): 2.0625 in / 52.388 mm
Inner ring width (B): 0.8750 in / 22.225 mm
Mating cup 372A outside diameter (D): 3.8125 in / 96.838 mm
Mating cup 372A width (C): 0.7500 in / 19.050 mm
Cone weight: 3.56 lb / 1.614 kg

Published ratings and mounting data

The ratings below are catalogue values for the complete 377/372A single-row assembly, not for the cone alone.

Dynamic radial rating C1 (1 million rev basis): 23,400 lbf / 104,000 N
Dynamic radial rating C90 (90 million rev basis): 6,070 lbf / 27,000 N
Dynamic axial rating Ca90: 3,520 lbf / 15,700 N
Static radial rating C0: 22,700 lbf / 101,000 N
K factor: 1.73 · e: 0.34 · Y: 1.77 · geometry factor Cg: 0.0816
Effective load centre: −0.15 in / −3.8 mm (inside the cone backface)
Maximum shaft fillet radius cleared: 0.09 in / 2.300 mm
Shaft backing shoulder diameter, frontface (da): 2.28 in / 58 mm
Shaft backing shoulder diameter, backface (db): 2.44 in / 62 mm
Cup 372A housing backing shoulder: Da 3.56 in / 90.42 mm, Db 3.39 in / 86.11 mm; max housing fillet 0.06 in / 1.52 mm

What these specs mean in practice

The 1.73 K factor puts this in the general-purpose middle of the range — real thrust capacity without giving up radial capability, and predictable induced thrust for the opposing bearing to absorb. Class 3 precision is what you buy when the cone has to hold a gear or pinion in mesh without wander, or when a pair is being set to a preload rather than an end play: the tighter bore and width tolerances make the resulting set repeatable instead of a shimming exercise. On a purely radial, loosely set position, standard Class 4 would do the same job for less.

Quantity and configuration

This listing ships 1 Pc — one 377-3 cone. No cup, no spacer, no seal. A normal two-bearing shaft needs two cones and two cups.

Fitting notes

Press the cone on square with the driver on the backface only, never through the rollers or cage. Keep the shaft shoulder within the da/db range. Plan the corners: the cone accepts a 0.09 in shaft fillet but the 372A cup only a 0.06 in housing fillet, so the housing corner must be sharper. Set the end play or preload after both cups are fully home — a Class 3 cone only pays for itself if the setting is done properly.

Interchange guidance

377 is a dimensionally standardised imperial cone, so 377 cones from Timken, Koyo, NTN, Bower/BCA, SKF and Federal-Mogul interchange with one another and with any maker’s 372A cup. The standard-precision 377 shares this envelope but not the Class 3 tolerance grade. 377A is a related size, not an equivalent, and 372 differs from 372A in cup detail — order the cup by number against your housing.