7311-BECBPH bearing: complete specifications & equivalents

The 7311-BECBPH is a ISO 15 radial bearing sized 55 x 120 x 29 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.

Bearing dimension schematic Front view shows outer diameter D and bore d; side section shows width B. D = 120 mm d = 55 B = 29 mm side section front view
Principal dimensions: bore d 55 mm, outer diameter D 120 mm, width B 29 mm. Schematic, not to scale.

Specification table

ParameterValue
Brand SKF
Bore diameter d 55 mm
Outer diameter D 120 mm
Width B 29 mm
Material GCr15
Seal / shield open
Internal clearance CN
Tolerance class P0
Cage polymer
Basic dynamic load rating C 85 kN
Basic static load rating C0 60 kN
Fatigue load limit Pu 2.55 kN
Reference speed (thermal) 7000 rpm
Limiting speed (mechanical) 7000 rpm
Operating temperature -40 to +120 °C
Mass 1400 g
Manufacturer designation 7311 BECBPH
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 & 7300-series range

Bore d 2.165 in
Outer diameter D 4.724 in
Width B 1.142 in
ISO bore code 11
Radial section height (D−d)/2 32.5 mm
Smallest bore in 7300-series 10 mm
Largest outer diameter in 7300-series 420 mm
Width range across 7300-series 11–80 mm
Bore position in 7300-series (smallest first) 12 of 31
Bore above smallest 7300-series size 45 mm

Cross references & equivalents

Equivalent modelBrandMatch levelNote
7311-BEP SKF full
Dimensions and internal design equivalent — standard interchange.
Same 55×120×29 mm envelope with catalogue ratings within 10 %; 7311 BEP is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs.
7311-BECBP SKF full
Dimensions and internal design equivalent — standard interchange.
Same 55×120×29 mm envelope with catalogue ratings within 10 %; 7311 BECBP is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs.
7311-BECBM SKF full
Dimensions and internal design equivalent — standard interchange.
Same 55×120×29 mm envelope with catalogue ratings within 10 %; 7311 BECBM is the brass cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs.
7311-BECBY SKF full
Dimensions and internal design equivalent — standard interchange.
Same 55×120×29 mm envelope with catalogue ratings within 10 %; 7311 BECBY is the brass cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs.
7311-ACCBM SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 55×120×29 mm envelope, but catalogue C/C0 differ between executions (85/60 kN vs 96.5/67 kN) — boundary dimensions match, not a load-rating equivalent.
QJ-311-N2MA SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 55×120×29 mm envelope, but catalogue C/C0 differ between executions (85/60 kN vs 137/118 kN) — boundary dimensions match, not a load-rating equivalent.
QJ-311-MA SKF partial
Main dimensions match; tolerances, seals or internal clearance differ.
Same 55×120×29 mm envelope, but catalogue C/C0 differ between executions (85/60 kN vs 137/118 kN) — boundary dimensions match, not a load-rating equivalent.
7311 SKF full
Dimensions and internal design equivalent — standard interchange.
SKF SKF 7311 BEP is the basic 55×120×29 mm angular-contact page with ratings within 10 % of this execution — same boundary dimensions, verify execution details.

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 7311-BECBPH model number is decoded

7311 BECBPH is SKF's 55 mm-bore single-row angular-contact ball bearing in the 7300 series, nominal 40° (B) contact angle, 55×120×29 mm to the ISO dimension plan. 40° contact angle (suffix B): the steep standard single-row angle, giving the highest axial capacity at the cost of speed, with a recommended load ratio Fa/Fr ≥ 1. E marks the optimized internal design with an enhanced ball complement and race geometry. glass-fibre reinforced PA66 cage, ball-centred (suffix P), with a 120 °C continuous-temperature ceiling. 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. BECBPH combines CB universal clearance with a PEEK ball-centred cage for hot, high-speed positions where PA66 is unsuitable. Envelope 55×120×29 mm (2.165×4.724×1.142 in), 32.5 mm radial section height, C 85 kN, C0 60 kN, Pu 2.55 kN.reference speed 7,000 r/min (thermal) and limiting speed 7,000 r/min (mechanical), which coincide for this size, catalogue mass 1400 g. Selection figures for 7311 BECBPH: the static-to-dynamic ratio C0/C is 0.71, Pu 2.55 kN is about 3 % of C, and catalogue mass works out to roughly 25 g per millimetre of bore. Envelope economics: the 29 mm width over a 32.5 mm section yields 0.89 mm of ring width per section millimetre, and the bearing weighs 1400 g for 85 kN of dynamic capacity — about 16 g per rated kN. Bore-to-OD planning: OD 120 over bore 55 is a 2.18× step for this size, and the 29 mm width gives a bore/width ratio of 1.90; use these ratios when housing space around the 55 mm shaft is the first constraint. PEEK cage note: the PH cage is moulded from glass-fibre reinforced polyetheretherketone, ball-centred, aimed at high-speed oil-air and grease positions where PA66 would approach its thermal and speed limits; it needs clean lubricant (PEEK cages are sensitive to hard-particle cage-wear) and is a separate order number from the brass BECBM.

Typical equipment & failure modes

Common applications

  • test-rig and balancing-machine shafts
  • machine-tool spindles and spindle units
  • servo drives and precision gearboxes

Known failure patterns

  • preload loss as a loosely clamped set runs slack and the balls smear the raceways
  • thermal preload runaway in a back-to-back pair when inner-ring heat cannot expand away
  • ball skidding when Fa/Fr stays below the 1,0 (40°) or 0,55 (25°) ratio and the contact ellipse is unloaded
  • PEEK cage wear from hard particles in the lubricant, which abrade the moulded pocket surfaces
  • brinelling from pressing the ring home through the balls or from static overload
  • brinelling from pressing the ring home through the balls or from static overload

Selection pitfalls — read before you substitute

  • At 55 mm bore the k5 seat assumes a steel shaft and housing; aluminium housings grow faster with temperature, so re-check the outer-ring setting when the case is non-ferrous.
  • Preload the set against a calculated stand-off dimension — the ground faces of BECBPH establish it, but locknut torque, sleeve crush and housing-face squareness each consume part of the allowance.
  • One 7311-BECBPH locates the shaft in one axial direction only; reversing-thrust positions need a DB or DF pair — or a double-row bearing — with preload set from the load diagram, never from assembly feel.
  • Mount by induction-heating the inner ring to max 120 °C — the PA66 cage sets the ceiling, not the steel; driving the bearing home through the outer ring or balls brinells the asymmetric raceway.
  • The steep 40° angle of 7311-BECBPH favours thrust-heavy combined loads; for a predominantly radial high-speed position the 25° ACCBM execution of the same size is the alternative order number.
  • Universally matchable BECBPH bearings arrive ready for set mounting, not preloaded sets: preload results from how the set is clamped, so follow the SKF stand-off-ring and nut-torque procedure.

Frequently asked questions

What are the dimensions and catalogue data of 7311-BECBPH?

7311 BECBPH measures 55 mm bore × 120 mm OD × 29 mm width (2.165 × 4.724 × 1.142 in), mass about 1400 g. SKF 17000 ratings: C 85 kN, C0 60 kN, Pu 2.55 kN, reference speed 7,000 r/min (thermal) and limiting speed 7,000 r/min (mechanical), which coincide for this size.

What does the BECBPH suffix mean?

40° contact angle (suffix B): the steep standard single-row angle, giving the highest axial capacity at the cost of speed, with a recommended load ratio Fa/Fr ≥ 1. E marks the optimized internal design with an enhanced ball complement and race geometry. glass-fibre reinforced PA66 cage, ball-centred (suffix P), with a 120 °C continuous-temperature ceiling. 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. BECBPH combines CB universal clearance with a PEEK ball-centred cage for hot, high-speed positions where PA66 is unsuitable.

What do the reference and limiting speeds mean for 7311-BECBPH?

The 7,000 r/min reference (thermal) and 7,000 r/min limiting (mechanical) speeds are catalogue conditions; preload, lubrication and heat removal move the permissible value, so re-calculate for the actual arrangement.

Can one 7311-BECBPH take thrust in both directions?

No. A single-row angular-contact bearing reacts axial load in one direction; reversing thrust needs a DB/DF matched pair (use a universally matchable CB/GA execution) or a double-row bearing. Under radial load the 40° angle induces an axial force that the arrangement must balance.

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.