3311-DMA bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the 3311-DMA model number is decoded

3311 DMA is SKF's 55 mm-bore double-row angular-contact ball bearing of the 3300 series — two ball rows back-to-back for two-direction axial location in one unit, 55×120×49.2 mm. A on a double-row bearing means no filling slots, so both rows carry their full ball complement in both directions. D marks a two-piece (split) inner ring that simplifies mounting of the heavy 33-series section. DMA pairs the split inner ring with a machined brass outer-ring-centred MA cage. Envelope 55×120×49.2 mm (2.165×4.724×1.937 in), 32.5 mm radial section height, C 111 kN, C0 100 kN, Pu 4.3 kN.reference speed 4,800 r/min (thermal) and limiting speed 5,000 r/min (mechanical), catalogue mass 2800 g. Sizing arithmetic on the 55 mm bore: 111 kN C divided by the 32.5 mm radial section height gives 3.4 kN per section millimetre; the 2800 g mass and 4 % Pu/C share frame the light-load floor for the adjusted-life check. Envelope economics: the 49.2 mm width over a 32.5 mm section yields 1.51 mm of ring width per section millimetre, and the bearing weighs 2800 g for 111 kN of dynamic capacity — about 25 g per rated kN. Speed-ratio note for this exact unit: the reference speed is 4,800 r/min against a 5,000 r/min limiting speed, i.e. a reference-to-limit ratio of 0.96. Split-ring execution note: DMA combines the two-piece inner ring (used to simplify mounting of the wide 33-series section) with a machined brass cage guided on the outer ring (MA rather than ball-centred M); outer-ring guidance steadies the cage in the heavy section at the cost of a different lubrication requirement at the guide land.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Controlled axial clearance is the heart of the design: the A execution is produced to the standard double-row axial clearance; check residual clearance after mounting and at operating temperature.
• Compared with a single-row pair of the same bore, the double-row 3311 occupies less axial space but offers less freedom to adjust preload — do not substitute without re-checking the arrangement.
• A capped 3311-2Z/-2RS1 execution of this envelope exists for sealed-for-life duty; an open double-row bearing needs application sealing and a defined lubricant supply.
• Compared with a single-row pair of the same bore, the double-row 3311 occupies less axial space but offers less freedom to adjust preload — do not substitute without re-checking the arrangement.
• The D executions have a two-piece inner ring: mount both halves square to each other, never press on the outer ring, and keep the split faces clean during fitting.
• Catalogue ratings are SKF PUB BU/P1 17000 figures for 3311 DMA as the double d ma execution; the other order numbers of the 3311 size are different products and may carry different ratings — always quote the full designation when purchasing.