FAGK24780Imperial Tapered Roller Bearing Cone, 1.6250 in / 41.275 mm Bore, Mates Cup 24720 – 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

In FAG and INA inch-series nomenclature the K- prefix means the cone — the inner ring complete with rollers and cage — so K-24780 is a cone by definition, never a complete bearing. The base number 24780 is the industry-standard imperial cone designation and its matching cup is 24720. A complete single-row bearing is therefore a 24780 cone plus a 24720 cup, assembling to a total width of 0.875 in / 22.225 mm.

Correcting the source data

Earlier copy on this listing gave the bore as 1-7/8 in. The published bore of a 24780 cone is 1.6250 in / 41.275 mm. Size your shaft to 1.6250 in.

Published dimensions

Cone bore (d): 1.6250 in / 41.275 mm
Inner ring width (B): 0.9063 in / 23.020 mm
Mating cup 24720 outside diameter (D): 3.0000 in / 76.2 mm
Mating cup 24720 width (C): 0.6875 in / 17.463 mm
Assembled 24780/24720 total width (T): 0.875 in / 22.225 mm
Cone weight: 2 lb / 0.908 kg

Published ratings and mounting data

The ratings below are catalogue values for the complete 24780/24720 single-row assembly, not for the cone alone.

Dynamic radial rating C1 (1 million rev basis): 17,000 lbf / 75,500 N
Dynamic radial rating C90 (90 million rev basis): 4,400 lbf / 19,600 N
Dynamic axial rating Ca90: 2,960 lbf / 13,200 N
Static radial rating C0: 20,100 lbf / 89,200 N
K factor: 1.49 · e: 0.39 · Y: 1.53 · geometry factor Cg: 0.0767
Effective load centre: −0.19 in / −4.8 mm (inside the cone backface)
Maximum shaft fillet radius cleared: 0.14 in / 3.600 mm
Shaft backing shoulder diameter, frontface (da): 1.85 in / 47 mm
Shaft backing shoulder diameter, backface (db): 2.13 in / 54 mm

What these specs mean in practice

A K factor of 1.49 is on the steep side for a general-purpose taper, meaning this bearing takes proportionally more thrust than a shallow 1.9-K design of the same envelope — and generates proportionally more induced thrust for the opposing bearing to absorb. That is why the 247xx family shows up in transfer-case output shafts and wheel-end positions where axial load is a constant rather than an occasional. The generous 0.14 in permissible shaft fillet radius makes it forgiving to fit on a shaft that was not machined to bearing-seat standards.

Quantity and configuration

This listing ships 1 Pc — one 24780 cone. No cup, no spacer, no seal.

Fitting notes

Press the cone on square, driving on the backface only and never through the rollers or cage. Keep the shaft shoulder within the da/db range. Note that the mating 24720 cup permits only a 0.03 in housing fillet radius, so the housing corner needs to be sharper than the shaft corner in this pairing. Set the end play or preload after the cup is fully seated.

Interchange guidance

24780 is a dimensionally standardised imperial cone, so FAG K-24780, Timken 24780, Koyo 24780, NTN 4T-24780, Bower/BCA 24780 and Federal-Mogul 24780 interchange with one another and with any maker’s 24720 cup. 24721 is a related cup size, not an equivalent to 24720 — it differs in width. Do not confuse the FAG K- cone prefix with a complete-bearing designation: if you need the whole bearing you must order the 24720 cup as well.