NSK7208A5TYDUMAngular Contact Ball Bearing Duplex Pair – 40 mm Bore, 80 mm OD, 18 mm Width, 25 Degree Contact Angle, Medium Preload, Open, Universally Ground

Product Description

What this part is
An NSK angular contact ball bearing supplied as a duplex pair at medium preload. Brand: NSK. Designation: 7208A5TYDUM. Base Number: 7208. Series: ISO 72 medium series at the 08 bore code, so the boundary dimensions follow the ISO standard.

Dimensions and mass (per single bearing)
Bore Diameter: 40 mm. Outside Diameter: 80 mm. Width: 18 mm. Total Mounted Width of the pair: 36 mm. Mass: 0.362 kg. Bore Type: Straight. Seal Type: Open.

Load ratings (per single bearing)
Basic Dynamic Load Rating (Cr): 44.0 kN. Basic Static Load Rating (C0r): 24.1 kN. Permissible Axial Load (Pa): 20.6 kN. Contact Angle: 25 deg (NSK A5 execution).

Mounting data
Contact Point Distance (a): 23.0 mm. Minimum Shaft Shoulder Diameter (da min): 47 mm. Maximum Housing Shoulder Diameter (Da max): 73 mm. Maximum Housing Bore Shoulder (Db max): 75 mm. Chamfer Dimension (r min): 1.1 mm. Chamfer Dimension (r1 min): 0.6 mm.

Decoding the designation
72 is the ISO dimension series and 08 the bore code, giving the 40 mm bore. A5 is NSK’s code for a 25 deg contact angle, read as one code: an A on its own denotes 30 deg in the NSK scheme, so the pairing of A with 5 is what fixes the angle at 25 deg. TY is a ball-guided cage. DU marks a duplex pair and M sets medium preload.

What these specs mean in practice
A 25 deg contact angle sits between the 15 deg high-speed setting and the 40 deg high-thrust setting, carrying appreciably more axial load than a 15 deg bearing in the same envelope. Medium preload gives more stiffness than light preload at the cost of higher running torque, which suits duty where positioning accuracy under load matters. The 7208 medium series is a heavier section than the 7008 light series at the same 40 mm bore, trading outside diameter and width for capacity.

Thrust direction and arrangement
A single-row angular contact ball bearing takes thrust in one direction only, set by which ring carries the high shoulder. The two bearings assembled as a duplex pair carry thrust in both directions, and the ground offset on the ring faces establishes the medium preload. Universal grinding means any two bearings of this designation may be arranged back-to-back, face-to-face or in tandem and will develop the specified preload when clamped.

Configuration
Supplied as 2 Pcs, two separate bearings forming one duplex pair. Arrangement: DUM, duplex universally ground set at medium preload. Rolling Elements: Balls. Number of Rows: 1 per bearing.

Interchange guidance
Genuine interchanges match series, angle, arrangement and preload: SKF 7208 ACD/P4ADMA uses the SKF AC code for 25 deg in a medium-preload pair, and FAG B7208-E-T-P4S-DUM uses the FAG E code for 25 deg. Same-envelope 7208 bearings at 15 deg (NSK C) or 30 deg (NSK A) are related sizes rather than interchanges, and light or heavy preload variants of the same number are likewise related rather than equivalent.