MRC5208MFFDouble-Row Angular Contact Ball Bearing, 40 x 80 x 30.2 mm, 30 Degree Contact Angle, Two Shields, 1 Pc

Product Description

What this part is

An MRC 5208MFF double–row angular contact ball bearing, 40 mm bore x 80 mm outside diameter x 30.20 mm (1–3/16 in) wide, with a 30° contact angle and a shield on each side. Two rows of balls run at opposed 30° angles inside a single pair of rings, so one bearing carries heavy radial load plus thrust in both directions and resists tilting moments — in roughly the axial space a single wide bearing occupies. Sold as 1 Pc.

Decoding the designation

5200 — the MRC double–row angular contact ball bearing series. It sits on the same envelope as the ISO 3200 series, which is why the carton also carries 3208.
08 — bore size code, 40 mm bore.
M — the MRC 5200–M build. It is the higher–capacity version of the same envelope: MRC publishes 49 500 N dynamic for the –M against 44 900 N for the plain –C build.
FF — two shields. This is the trap on MRC bearings, so read it carefully: on MRC, FF means shields and ZZ means rubber seals — the opposite way round from most makers. This bearing is the shielded one.

Correcting the source data

Earlier copy on this listing gave a 25° contact angle, a 42.9 kN dynamic rating and a 7 000 rpm limiting speed. MRC’s own catalogue for the 5208–MFF publishes 30° contact angle, 49 500 N (49.5 kN) dynamic and 49 000 N static, with speed ratings of 5 600 rpm on grease and 7 500 rpm on oil. Those are the figures to design to. The old 42.9 kN number belongs closer to the plain 5208–C build, which is a different, lower–capacity bearing on the same envelope.

What these specs mean in practice

A double–row angular contact bearing is what you fit when a position has to take thrust in both directions and you do not have room — or the assembly tolerance — for a matched pair of single–row bearings. The two opposed 30° ball rows are ground into one set of rings at the factory, so the internal preload relationship is fixed and there is nothing to set at assembly. That makes it a genuinely rigid, drop–in locating bearing: it resists tilting moments in a way a deep groove ball bearing cannot.

The 30° angle is the middle of the road. A shallower angle would give more radial capacity and higher speed; a steeper one more thrust. At 30° you get a good share of both, which is why the 5200 series ends up in pumps, gearboxes, machine tool feed screws and vertical shafts.

Two shields make this a mostly–maintenance–free bearing: they keep coarse contamination out and grease in without the drag and temperature rise a contact seal adds, which is why the shielded speed rating is the same 5 600 rpm as the grease rating rather than being derated.

Published ratings and mounting data

Bore 40.000 mm; outside diameter 80.000 mm; width 30.20 mm (1–3/16 in).
Contact angle 30°; two rows of balls.
Basic dynamic radial load rating C 49 500 N.
Basic static radial load rating C0 49 000 N.
Speed rating 5 600 rpm on grease, 7 500 rpm on oil; shielded speed rating 5 600 rpm.
Maximum shaft and housing fillet radius ra 1.00 mm.
Closure: two shields.

Quantity and configuration

One bearing per order — 1 Pc. This is a single complete bearing: both rings, both ball rows, cage and both shields as one non–separable unit. Nothing else is needed to make it work — 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 taking the interference fit and never through the balls. Keep shaft and housing fillets inside 1.00 mm radius or the bearing will not seat square against its shoulders. Because the bearing takes thrust both ways, it must be clamped axially on both rings — a double–row angular contact bearing left free to float in the housing cannot do the job it was chosen for. And do not attempt to adjust preload: it is built in, and trying to squeeze it by over–clamping will only shorten the life.

Interchange guidance

The 40 x 80 x 30.2 mm double–row angular contact envelope is the ISO 3208, so SKF 3208 A–2Z, FAG 3208–B–2Z–TVH, NSK 3208B–2ZTN and NTN 5208ZZ all fit the same seat. Two things to watch when substituting. First, contact angle: MRC’s 5200 series is 30°, while FAG’s 32xx–B–TVH runs 25° and its current 32xx–BD–XL 30° — a same–envelope part at a different angle is a related size, not a like–for–like replacement. Second, closure: the 5208ZZ and 3208–2Z forms carried in this listing are the shielded bearing in other makers’ nomenclature, and they are here for search, but remember that MRC’s own ZZ code means rubber seals. MRC bearings are now part of SKF, so SKF is the route to current supply.