NSK7211C1TDTP4Angular Contact Ball Bearing – 55 mm Bore, 100 mm OD, 21 mm Width, 15° Contact Angle, Machined Phenolic Cage, ABEC 7, Tandem Pair

Product Description

What this part is

NSK 7211C1TDTP4 is a super-precision single-row angular contact ball bearing in the ISO 72 dimension series, supplied as a factory tandem duplex set. Bore Diameter: 55 mm. Outside Diameter: 100 mm. Overall Width: 21 mm per bearing. Contact Angle: 15°. Precision Class: ABEC 7 / P4. Cage Material: Phenolic. Cage Type: Machined, outer-ring guided. Rolling Elements: Ball. Number Of Rows: 2. Bore Type: Straight. Closure Type: Open. Mounting Arrangement: Tandem (DT). Bearing Material: Chrome steel. Lubricant: Grease or oil. Series: 72. Base Number: 7211. Unit Quantity: 2 Pcs.

Decoding the designation

7211 — NSK’s number for the ISO 7211 size, 55 x 100 x 21 mm.

C — 15° contact angle.

T — machined phenolic cage.

DT — tandem duplex pair.

P4 — ISO Class 4, ABEC 7 precision.

What these specs mean in practice

Dynamic Load Rating: 66,500 N. Static Load Rating: 40,000 N. Permissible axial load (Pa): 27,600 N. Limiting Speed: 14,900 rpm grease; 22,600 rpm oil. A 15° contact angle puts the ball path closer to the radial plane, which buys speed and radial stiffness and trades away axial capacity against a 25° or 40° execution of the same size. The machined phenolic cage rides on the outer ring land and stays quiet at the speeds this class is rated for.

Mounting data

Effective load centre (a): 20.9 mm. Shaft abutment diameter (da min): 64 mm. Housing abutment diameter (Da max): 91 mm. Second housing abutment diameter (Db max): 94 mm. Chamfer (r min): 1.5 mm. Chamfer (r1 min): 1.0 mm. Shaft and housing fillet radius (ra max): 1.5 mm. Fillet radius (rb max): 0.8 mm. Calculation factor f0: 14.5.

Quantity and configuration

Unit Quantity: 2 Pcs. Tandem duplex pair. Both bearings face the same direction and share the axial load between them. Total width across the pair: 42 mm.

Interchange guidance

The same bearing is written 7211C, 7211CTDTP4, 7211-C1-T-DT-P4 and 7211C1TDTP4.

Cross-Reference 1: Fafnir 2MM211WICRDU (related, P4S). Cross-Reference 2: SKF 7211 CD/P4ADGA (related, P4A). Cross-Reference 3: FAG B7211-C-T-P4S-UL (related, P4S). Cross-Reference 4: RHP 7211CTDUP4. Cross-Reference 5: NTN 7211CDT/GNP4. Cross-Reference 6: Koyo 7211CDT. Cross-Reference 7: NTN-SNR 7211CDT. Cross-Reference 8: Nachi 7211CDT. Cross-Reference 9: NSK 7211C, the single-bearing base designation.

Every number above shares the 55 x 100 x 21 mm envelope and the 15° contact angle. Where a class is stated in brackets the part is built to a P4S or P4A grade rather than P4, so it is a related size rather than a like-for-like interchange. The ISO 7211 envelope is also shared with the 25° and 40° executions 7211A5 and 7211B, which drop into the same shaft and housing and move the load split between radial and axial.