MRC5211CDouble-Row Angular Contact Ball Bearing, 55 x 100 x 33.3 mm, 30 Degree Contact Angle, Open, Normal Clearance, 1 Pc

Product Description

What this part is

An MRC 5211–C double–row angular contact ball bearing, 55 mm bore x 100 mm outside diameter x 33.30 mm (1–5/16 in) wide, 30° contact angle, open with no shields or seals and normal internal clearance. Two rows of balls run at opposed 30° angles inside one pair of rings, so a single bearing carries heavy radial load plus thrust in both directions and resists tilting moments. Sold as 1 Pc.

Decoding the designation

5200 — the MRC double–row angular contact ball bearing series, sharing the ISO 3200 envelope. That is why the carton also carries 3211.
11 — bore size code, 55 mm bore.
C — the MRC 5200–C build: open, with no shield and no seal.

What these specs mean in practice

Reach for a double–row angular contact bearing when a shaft has to be located against thrust in both directions and there is no room — or no appetite for the setting work — for a matched pair of single–row bearings. Both 30° ball rows are ground into one set of rings at the factory, so the preload relationship is fixed and there is nothing to adjust on the bench. The result is a rigid, drop–in locating bearing that resists tilting moments in a way a deep groove ball bearing cannot.

The 30° angle sits in the middle of the range. Shallower angles favour radial capacity and speed; steeper ones favour thrust. At 30° you get a usable share of both, which is why the 5200 series shows up in pumps, gearboxes, machine tool feed screws and vertical shafts where the shaft weight itself is an axial load.

Being open cuts both ways: it is right where the housing has its own seals or runs an oil bath and you do not want the drag of a shield, and it is wrong in dirt, because nothing keeps contamination out of the raceways. Note the speed ratings drop against the smaller 5208 — 4 300 rpm on grease here against 5 600 — because a larger ball pitch diameter means higher surface speed at the same shaft rpm.

Published ratings and mounting data

Bore 55.000 mm; outside diameter 100.000 mm; width 33.30 mm (1–5/16 in).
Contact angle 30°; two rows of balls.
Basic dynamic radial load rating C 57 200 N.
Basic static radial load rating C0 47 500 N.
Speed rating 4 300 rpm on grease, 5 600 rpm on oil.
Maximum shaft and housing fillet radius ra 1.50 mm.
Normal radial internal clearance. Closure: open, no shield and no seal.

Quantity and configuration

One bearing per order — 1 Pc. A single complete non–separable bearing ships: both rings, both ball rows and cage. Nothing else is required — unlike a matched pair of single–row angular contact bearings, a double–row bearing is a complete locating unit on its own.

Fitting notes

Press only on the ring that takes the interference fit, never through the balls. Keep shaft and housing fillets inside 1.50 mm radius so the rings seat square against their shoulders — that figure is larger than on the 5208, so a shaft machined for the smaller bearing may need its fillet checked. Clamp the bearing axially on both rings, because it is there to take thrust in both directions and cannot do that floating. Do not attempt to adjust preload; it is built in. As an open bearing, grease it properly on the bench and keep the raceways clean during assembly.

Interchange guidance

The 55 x 100 x 33.3 mm double–row angular contact envelope is the ISO 3211, so SKF 3211 A, FAG 3211–B–TVH, NSK 3211BTN and NTN 5211 all fit the same seat. Check the contact angle before you substitute: MRC’s 5200 series is 30°, while FAG’s 32xx–B–TVH runs 25° and its current 32xx–BD–XL runs 30°. A same–envelope bearing at a different angle is a related size, not a like–for–like replacement. Shielded and sealed builds on this envelope — 3211–2Z, 3211 A–2RS1 and MRC’s own –MFF and –ZZ codes — are likewise related sizes rather than direct swaps for an open bearing, and remember that on MRC a ZZ suffix means rubber seals, not shields. MRC bearings are part of SKF, which is the route to current supply.