Timken456Precision Tapered Roller Bearing Cone Only (Inner Ring & Rollers), 2-1/8 in Bore x 1.1542 in Wide, Class 3 Precision — Cup Not Included

Product Description

What this part is — and what is not in the box:
This is a cone only: the inner ring of a single-row imperial tapered roller bearing, complete with its tapered rollers and cage. It is not a complete bearing. The outer ring — the cup, sometimes called the outer race — is a separate Timken part number and is not included in this listing. You cannot run this component on its own. If you are replacing a whole bearing rather than just a worn cone, you need to source the mating cup as well, and the cup part numbers are listed below so you can order the set.

Tapered roller bearings are built this way on purpose. Because cone and cup are separable, a rebuilder can press the cone onto the shaft and the cup into the housing independently, and can replace just the component that failed. Selling cones and cups separately is normal Timken practice, not an omission — but it does mean you have to check which one you are buying.

Decoding the designation

456 — the Timken cone part number, 2.1250 in bore.
3 — Timken precision Class 3. On the actual carton this appears boxed, in the position Timken uses for the precision class, which is why the part is commonly written 456-3.
0000 — the trailing group on the carton. On Timken precision tapered roller cartons this field carries the bench-gauge / standoff setting information for the ground component. All zeros indicates the nominal, unmodified setting rather than a special standoff. We are reporting what is printed; Timken does not publish a public decode table for this field, so we are not stretching it further.
Full designation as printed on the box: 456 · 3 · 0000.

What Class 3 precision actually buys you

Timken’s inch tapered roller precision ladder runs, from loosest to tightest, Class 4 (standard industrial), then Class 2, Class 3, Class 0 and Class 00. So Class 3 is a genuine precision-ground component two steps above the standard Class 4 part that the same 456 number would otherwise supply. In practice that tighter grade buys you closer control over bore and race dimensions and, most importantly, lower radial and axial runout — the amount the race wobbles as the ring turns.

Why that matters: runout in a tapered roller bearing propagates straight into shaft position. On a machine-tool spindle, a printing or converting roll, a gear reducer with tight backlash requirements, or a pump with close-clearance impellers, a standard-class bearing will hold the load perfectly well and still leave you with vibration, uneven gear tooth loading or unacceptable surface finish. Class 3 is what you specify when the shaft has to stay where you put it. It also makes the bearing repeatable: two Class 3 cones from the same class will set up to nearly the same endplay, which matters if you are building a matched pair. Distributors often characterise Class 3 as roughly equivalent to ABEC 5; that is a distributor comparison rather than a Timken statement, and the tapered roller and ball bearing tolerance systems are not directly interchangeable, so treat it as a rough indication only.

The practical warning: a Class 3 cone only delivers Class 3 results if the cup, the shaft seat and the housing bore are machined to match. Fitting a precision cone into a worn housing with a standard cup gets you a standard bearing at a precision price.

Mating cups you can order to complete the bearing:
Timken lists the following cups as running with the 456 cone: 452, 452A, 453, 453A, 453AS, 453B, 453X, 454. They differ in outside diameter, width and flange or seal features, so pick the one your housing is bored for. The most commonly paired cups are 452 and 452A, and Timken publishes the 456/452A assembly as follows: outside diameter 4.25 in / 107.95 mm, assembled width (T) 1.2818 in / 32.558 mm, cup width (C) 1.063 in / 27 mm. If your housing bore is not 4.25 in, you are on a different cup in that list and should confirm before ordering.

Published cone data

From The Timken Company’s own catalogue entry for cone 456.

Bore (d): 2.1250 in / 53.975 mm
Inner ring width (B): 1.1542 in / 29.317 mm
Dynamic radial load rating C1 (ISO, 1 million revs): 36,100 lbf / 161,000 N
Dynamic radial load rating C90 (Timken method, 90 million revs): 9,370 lbf / 41,700 N
Dynamic axial rating Ca90: 5,380 lbf / 23,900 N
Static radial load rating C0: 37,200 lbf / 166,000 N
K factor: 1.74
G1 factor 58.6 · G2 factor 17.1 · geometry factor Cg 0.0946
Effective centre location: −0.28 in / −7.1 mm (inside the cone backface)
Shaft backing shoulder diameter: 2.4 in / 61 mm frontface (da), 2.68 in / 68 mm backface (db)
Maximum shaft fillet radius: 0.14 in / 3.600 mm
Cage location relative to backface (Aa): 0.07 in / 1.8 mm · relative to frontface (Ab): 0.08 in / 2 mm
Catalogue weight: 6.53 lb / 2.963 kg
With cup 452A: e factor 0.34, Y factor 1.79, housing backing shoulder Da 3.96 in / 100.10 mm, Db 3.66 in / 92.96 mm, maximum housing fillet radius 0.130 in / 3.30 mm

Quantity and configuration

One cone. The photographs show a single component wrapped in Timken preservative paper alongside its original Timken PRECISION carton — one item, not a pair and not a cone-and-cup set. Tapered rollers are usually mounted in opposing pairs, so a two-bearing shaft rebuild needs two cones and two cups; only one cone is in stock here.

Fitting notes

Keep the shaft shoulder inside the published da/db window and the shaft fillet radius at or below 0.14 in so the cone corner clears. Drive the cone on the inner ring face only, never through the rollers, and heat-fit rather than hammer-fit if you can — a precision-class ring does not forgive impact. This is new old stock: the component is still in its factory preservative wrap and the carton shows age and shelf wear, with a handwritten stores marking (“B34-025”) on the label. Inspect the preservative coating and re-lubricate to your application’s specification before commissioning. Set endplay or preload against the cup in the housing once both are seated.

Interchange guidance

456 is an industry-standard ANSI/ABMA imperial cone number, also carried by SKF, NTN, Koyo, NSK and others for the same boundary dimensions. Those crosses are dimensional only — they will not normally be precision Class 3, and a standard-class substitute defeats the reason to buy this part. Verify the seller’s tolerance class before treating any cross as a like-for-like replacement. Timken is the successor brand to Fafnir and to Torrington, so legacy references from those lines may lead here.