Fafnir5209WDouble Row Angular Contact Ball Bearing, 45 mm Bore x 85 mm OD x 30.17 mm Wide, 30 Degree Contact Angle, Snap-In Cage

Product Description

What this part is

A Fafnir 5200-series double row angular contact ball bearing. Two rows of steel balls run on a one-piece inner ring and a one-piece outer ring at a 30° contact angle, arranged back-to-back inside a single bearing. Because both rows are ground into one bearing at the factory, the axial clearance is set by the manufacturer — you do not shim or preload it during assembly the way you would a pair of separate single-row angular contacts.

What the 30° contact angle buys and costs

Contact angle is the trade-off that decides whether this bearing suits your shaft. At 30° the load path runs steeply through the rings, which gives high thrust capacity and good axial stiffness in both directions. The cost is radial capacity and speed: a deep groove ball bearing of the same envelope will spin faster and tolerate more pure radial load, and a shallower 15° angular contact will spin faster still. Choose 30° when thrust and axial rigidity are the problem, not when speed is.

Manufacturer figures (from Timken’s own catalogue entry for 5209W):

Bore (d): 45 mm
Outside diameter (D): 85 mm (3.3456 in)
Width (C): 30.17 mm (1.188 in)
Contact angle: 30°
Rows: 2
Ball type: steel
Cage type: snap-in
Dynamic radial load rating C1 (1 million revolutions): 14,600 lbf / 64,800 N
Static radial load rating C0: 11,600 lbf / 51,500 N
Max shaft fillet radius: 0.039 in / 1 mm
Outer ring to-clear radius: 0.039 in / 1 mm
Shaft backing shoulder diameter: 2.324 in / 59.03 mm
Housing backing shoulder diameter: 3.014 in / 76.56 mm
Design units: metric

Correcting the source data

Several distributor listings for this part quote 14,200 lbf dynamic and 11,500 lbf static. Timken’s own catalogue entry gives 14,600 lbf (64,800 N) and 11,600 lbf (51,500 N). The figures above are the manufacturer’s.

Fitting notes

The shaft and housing backing shoulder diameters above are the abutment sizes that will actually clear the bearing corners — 2.324 in on the shaft and 3.014 in in the housing. Undersize either shoulder and you load a ring face instead of supporting it. Keep shaft and housing fillet radii at or below 1 mm. Mount by pressing on the ring that is being fitted, never through the balls, and note that a back-to-back double row bearing normally goes in as the locating (fixed) position with a floating bearing elsewhere on the shaft.

Quantity and configuration

One bearing per unit. This is a self-contained double row bearing, not half of a matched pair, so nothing else has to be bought to make it work.

Interchange guidance

3209 is the ISO-style designation for a 45 x 85 x 30.2 mm double row angular contact ball bearing and is the number to search on for other brands in the same envelope. Fafnir became a Timken brand, so current-production stock of this number ships as Timken (Fafnir). Distributors also list neighbouring variants such as 5209WD and 5209WG — these are separate part numbers with different closures and cages and should not be substituted without checking those two details against your application.