3311-DNRCBM bearing: complete specifications & equivalents
The 3311-DNRCBM is a ISO 15 radial bearing sized 55 x 120 x 49.2 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 49.2 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 95.6 kN |
| Basic static load rating C0 | 83 kN |
| Fatigue load limit Pu | 3.55 kN |
| Reference speed (thermal) | 5000 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2550 g |
| Manufacturer designation | 3311 DNRCBM |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
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.
Dimensions in inches & 3300-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.937 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 32.5 mm |
| Smallest bore in 3300-series | 15 mm |
| Largest outer diameter in 3300-series | 240 mm |
| Width range across 3300-series | 19–92.1 mm |
| Bore position in 3300-series (smallest first) | 10 of 20 |
| Bore above smallest 3300-series size | 40 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3311-DMA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×49.2 mm envelope, but catalogue C/C0 differ between executions (95.6/83 kN vs 111/100 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3311-A | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×49.2 mm envelope, but catalogue C/C0 differ between executions (95.6/83 kN vs 112/81.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3311-ATN9 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×49.2 mm envelope, but catalogue C/C0 differ between executions (95.6/83 kN vs 112/81.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3311-A-2Z | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×49.2 mm envelope, but catalogue C/C0 differ between executions (95.6/83 kN vs 112/81.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3311-A-2RS1 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×49.2 mm envelope, but catalogue C/C0 differ between executions (95.6/83 kN vs 112/81.5 kN) — boundary dimensions match, not a load-rating equivalent. |
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-DNRCBM model number is decoded
3311 DNRCBM 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. NR adds a snap-ring groove in the outer ring supplied with the appropriate snap ring, and CB gives controlled axial clearance. DNRCBM combines the split inner ring, snap ring (NR), controlled CB clearance and a machined brass ball-centred M cage. CB means universally matchable with Normal axial internal clearance: the two side faces are ground so any two units form DB (back-to-back), DF (face-to-face) or DT (tandem) sets without regrinding. Envelope 55×120×49.2 mm (2.165×4.724×1.937 in), 32.5 mm radial section height, C 95.6 kN, C0 83 kN, Pu 3.55 kN.reference speed 5,000 r/min (thermal) and limiting speed 5,300 r/min (mechanical), catalogue mass 2550 g. Load balance: C0 83 kN against C 95.6 kN gives a 0.87 ratio, typical of a double-row bidirectional design; Pu 3.55 kN enters the SKF adjusted-life equation rather than the basic rating life. Speed planning distinguishes the two published ceilings mechanically: the cage and balls tolerate 5,300 r/min while thermal balance under catalogue load sets the 5,000 r/min reference; at dm ≈ 87.5 mm the corresponding dn is approximately 464k mm·r/min. Speed-ratio note for this exact unit: the reference speed is 5,000 r/min against a 5,300 r/min limiting speed, i.e. a reference-to-limit ratio of 0.94.
Typical equipment & failure modes
Common applications
- printing and converting machinery
- gearbox input and output shafts with bidirectional thrust
- two-direction thrust positions without room for a paired single-row set
Known failure patterns
- loss of controlled axial clearance (CB) after thermal growth removes residual play
- tilted mounting that loads one double row more heavily than the other
- snap-ring groove distress or ring rotation if the NR snap ring is not seated fully in its groove
- electrical pitting on VFD-driven shafts without grounding protection
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- Catalogue ratings of 95.6/83 kN apply to the DNRCBM execution; the D and DNRCBM two-piece-ring executions carry their own figures on their own pages.
- The double-row 3311 takes thrust in both directions by itself — that is the reason to choose it over two single-row bearings: one housing bore, one fit, built-in set geometry.
- 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.
- 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 DNRCBM as the double d nr cb m execution; the other order numbers of the 3311 size are different products and may carry different ratings — always quote the full designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 3311-DNRCBM?
3311 DNRCBM measures 55 mm bore × 120 mm OD × 49.2 mm width (2.165 × 4.724 × 1.937 in), mass about 2550 g. SKF 17000 ratings: C 95.6 kN, C0 83 kN, Pu 3.55 kN, reference speed 5,000 r/min (thermal) and limiting speed 5,300 r/min (mechanical).
What does the DNRCBM suffix mean?
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. NR adds a snap-ring groove in the outer ring supplied with the appropriate snap ring, and CB gives controlled axial clearance. DNRCBM combines the split inner ring, snap ring (NR), controlled CB clearance and a machined brass ball-centred M cage. CB means universally matchable with Normal axial internal clearance: the two side faces are ground so any two units form DB (back-to-back), DF (face-to-face) or DT (tandem) sets without regrinding.
Does the 3311 double-row bearing need pairing?
No — both ball rows are built into one bearing, so bidirectional location does not require a second unit. Controlled axial clearance is part of the design rather than a field adjustment.
Which fits should I use?
With a rotating inner ring use roughly k5 on the 55 mm shaft and H7 in the 120 mm housing; check the wide ring seats square because the 49.2 mm width is sensitive to tilt.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.