NTN2210SKC3Double-Row Self-Aligning Ball Bearing, 50 x 90 x 23 mm, 1:12 Tapered Bore, C3 Clearance, Open, 1 Pc

Product Description

What this part is

An NTN 2210 K double–row self–aligning ball bearing, 50 mm bore x 90 mm outside diameter x 23 mm wide, with a 1:12 tapered bore and C3 clearance. Two rows of balls run in two deep grooves in the inner ring and on one common sphered raceway in the outer ring. Because that outer raceway is a section of a sphere, the inner ring and ball set tilt freely inside the outer ring, so the bearing shrugs off shaft deflection and housings that are not in line. Sold as 1 Pc.

Decoding the designation

22 — the wide self–aligning ball series. The 12xx series is the narrow equivalent on the same bore and outside diameter.
10 — bore size code, 50 mm bore.
K — tapered bore, taper 1:12. NTN also writes the tapered–bore version of this bearing as 2210S K, which is why both forms appear on this listing.
C3 — radial internal clearance greater than normal.

What these specs mean in practice

A tapered bore is a different mounting system, not a variant of a straight bore. The bearing is driven up a matching 1:12 taper, and the further it goes on, the more the inner ring expands and the more internal clearance disappears. You therefore set the running clearance at assembly instead of buying it — which is how a plain, unmachined shaft gets a tight, creep–free inner ring fit. The C3 starting clearance gives you the room to do that drive–up without ending up preloaded.

In almost every installation the taper comes from an adapter sleeve, not the shaft. For a 2210 K that sleeve is an H310, which has a 45 mm bore, so the assembly mounts on a plain 45 mm shaft and clamps up with a KM10 lock nut and MB10 lock washer. Sleeve, nut and washer are separate items and are not included here. If your shaft already carries a machined 1:12 taper, the bearing goes straight on.

As a self–aligning ball bearing this is a radial–load part with modest thrust capacity, and its static rating is well below its dynamic rating — correct and published for this family, because the sphered outer raceway has a smaller contact area than a deep–groove raceway. It shrugs off running load and is less happy with standing shock load.

Published ratings and mounting data

Bore 50 mm (tapered 1:12), outside diameter 90 mm, width 23 mm.
Two rows of balls; open, no seals or shields.
Radial internal clearance C3, greater than normal.
Matching adapter sleeve H310 — 45 mm shaft bore. Lock nut KM10, lock washer MB10.
Envelope reference capacity for the 2210 size: SKF 2210 ETN9, dynamic 33.8 kN, static 11.2 kN, mass 0.55 kg. Cage design shifts the figures slightly, so treat these as the reference for the envelope.

Quantity and configuration

One bearing per order — 1 Pc. What ships is the bearing only: outer ring, both ball rows, cage and inner ring, as one non–separable unit. No adapter sleeve, lock nut or lock washer is included. A tapered–bore bearing cannot mount without the sleeve or a tapered shaft seat, so budget for an H310 plus KM10 and MB10 if you do not already have them.

Fitting notes

Drive the bearing up the taper with the lock nut and measure as you go — drive–up distance is what sets the residual internal clearance, and overdoing it preloads the balls and ruins the bearing. Check clearance with a feeler gauge between the outer ring raceway and an unloaded ball, or work to the sleeve drive–up table. Bend a tab of the MB10 washer into a slot in the sleeve once the setting is right. Do not clamp or shim the outer ring square: it is meant to tilt, and squaring it throws away the self–aligning function you paid for.

Interchange guidance

The 50 x 90 x 23 tapered–bore self–aligning ball envelope is standard, so SKF 2210 EKTN9/C3, FAG 2210–K–TVH–C3, NSK 2210KC3 and Koyo 2210KC3 all fit the same seat and take the same H310 sleeve. Match two things: the clearance class, which is C3 here, and the bore type. The straight–bore 2210 is a related size on the same envelope rather than an equivalent — it will not go on an adapter sleeve, and this one will not sit on a plain shaft. The 1210 K shares the bore and outside diameter but is narrower, so it too is a related size rather than a substitute.