Fafnir2MM9117WI-DULSuper Precision Angular Contact Ball Bearing, Matched Duplex Pair, 85 x 130 x 22 mm, 44 mm Total Width, 15 Degree Contact Angle, Light Preload, Phenolic Outer Land Riding Cage, ISO P4S

Product Description

What this part is

Fafnir 2MM9117WI-DUL super precision angular contact ball bearing set from Timken, supplied as a duplex universally ground pair at light preload. Brand: Fafnir (Timken). Bore: 85 mm. Outside Diameter: 130 mm. Overall Width: 22 mm per bearing. Total Width: 44 mm. Contact Angle: 15°. Preload: Light. Precision Rating: ISO P4S (ABEC 7/9). Arrangement: DU, duplex universally ground. Number Of Rows: 1 per bearing. Cage Type: CR — Phenolic Outer Land Riding Cage. Cage Material: Phenolic, Timken cage designation MBR. Ball Type: Steel. Bearing Material: Chrome steel. Closure Type: Open. Bore Type: Straight. Design Units: Metric. Series: 9100WI. Base Number: 2MM9117WI. Harmonization Code: 8482.10.50.28. Timken World Part Number: 7017C-T-P4S-DUL.

Published ratings and mounting data

Dynamic Load Rating (C1), duplex set, 1 million revolutions: 66,700 N / 15,000 lbf. Dynamic Load Rating per row, C1 ISO: 60,500 N / 13,600 lbf. Static Radial Load Rating (C0): 58,700 N / 13,200 lbf. Limiting Speed, grease: 9,700 rpm. Limiting Speed, oil: 19,400 rpm. Maximum Shaft Fillet Radius: 1 mm. Shaft Backing Shoulder Diameter: 94.1 mm. Housing Backing Shoulder Diameter: 122.1 mm. Outer Ring To-Clear Radius: 1 mm.

Decoding the designation

2MM: Fafnir super precision metric series, 15° contact angle. The 3MM prefix is the 25° form. 9117: 9100WI dimension series with ISO bore code 17, giving an 85 mm bore and the 7017 envelope, 85 x 130 x 22 mm. WI: low shoulder on both rings. CR: phenolic outer land riding cage, Timken designation MBR. DU: duplex universally ground. L: light preload. The MM prefix carries ISO P4S. Searchable forms: 2MM9117WI-DUL, 2MM9117WIDUL, 2MM-9117-WI-DUL, 2MM 9117 WI DUL, 2MM9117WICRDUL, 7017C-T-P4S-DUL, 7017C, 7017.

What these specs mean in practice

15° is the high-speed end of the spindle-bearing range. A shallower contact angle puts the load path closer to the radial plane, which reduces ball centrifugal and gyroscopic effects at speed and generates less heat, so a 15° set runs faster and cooler than a 25° set in the same envelope. What it gives up is axial stiffness and thrust capacity.

Light preload compounds that choice in the same direction: least stiffness, least heat, highest speed capability of the three preload grades, which is why light preload is the normal specification for high-speed spindles.

The phenolic outer land riding cage is what makes those speeds usable at 85 mm bore. Phenolic is light and mildly self-lubricating, so it generates far less heat than a steel cage, and riding on the outer ring land lets centrifugal force stabilise the cage rather than load it.

Universal grinding means the ring faces are flush ground to a controlled offset, so the pair mounts back-to-back for the widest effective bearing spread and the best resistance to moment loads, face-to-face for tolerance of slight misalignment, or in tandem to double thrust capacity in one direction. The preload is ground into the ring faces, so no shim stack or clearance setting is involved.

Quantity and configuration

Unit Quantity: 2 Pcs, one matched duplex pair. Total Width: 44 mm. One row of balls per bearing.

Interchange guidance

Timken publishes the world equivalent as 7017C-T-P4S-DUL, and the source designation 7017-C agrees with it: in Timken’s scheme C is 15°. A matching substitute carries the 15° contact angle, ISO P4S grade, phenolic cage, light preload and duplex universally ground faces in the 85 x 130 x 22 mm envelope. Related sizes in the same envelope: SKF 7017 CD/P4ADGA, the 25° 3MM9117WI or 7017E, and clearance-graded or steel-caged 7017 bearings. Angle letters differ between makers: NSK reads C as 15°, A as 30° and A5 as 25°, and SKF reads AC as 25°.