31309T62-5-DB bearing: complete specifications & equivalents
The 31309T62-5-DB is a ISO 355 radial bearing sized 45 x 100 x 62.5 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 45 mm |
| Outer diameter D | 100 mm |
| Width B | 62.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 194 kN |
| Basic static load rating C0 | 204 kN |
| Fatigue load limit Pu | 24.5 kN |
| Reference speed (thermal) | 4000 rpm |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2100 g |
| Manufacturer designation | SKF 31309T62.5/DB |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants |
| Last verified | 2026-09-29 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants) · extracted 2026-09-29
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants); 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 & matched-db-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 2.461 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in matched-db-series | 35 mm |
| Largest outer diameter in matched-db-series | 480 mm |
| Width range across matched-db-series | 41.5–288 mm |
| Bore position in matched-db-series (smallest first) | 3 of 30 |
| Bore above smallest matched-db-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 31309T62 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 31309T62-5-DB model number is decoded
In the back-to-back (O) arrangement the load lines diverge toward the shaft axis, giving the pair a wide effective spread: 31309T62-5-DB resists overturning moments and tilting loads stiffly, which is why O-sets are preferred for gearbox output shafts and pinion supports. Catalogue mass 2100 g covers both bearings and the ground spacer of 31309T62-5-DB; keep the set complete — substituting one bearing or a non-ground spacer destroys the factory clearance. Dimensional interchange map: within its boundary plan the 45×100×62.5 mm envelope of 31309T62-5-DB is fixed, so shoulder, spacer and seal drawings can be dimensioned straight from the catalogue table. Spacer discipline: the spacer between the two bearings of 31309T62-5-DB is ground to the individual set — it carries a serial link to the pair, so never swap spacers between sets of the same designation. Lubrication for the pair should be sized against the combined 62.5 mm width and 2100 g mass: two roller sets sweep twice the contact area of a single bearing of the same bore.31309T62-5-DB is a matched pair of single-row tapered roller bearings arranged back-to-back (O) matched pair, supplied by SKF in SKF catalogue PUB BU/P1 17000 as one factory-set unit: the two bearings, spacers and setting are matched together and must not be mixed with other sets.Reading the designation: 31309T62.5 is the ISO 355 single-row base bearing (45 mm bore), and the suffix /DB marks the matched-set execution — arrangement, spacer grinding and factory clearance class. The pair envelope is 45×100×62.5 mm; the width covers both bearings of the set.
Typical equipment & failure modes
Common applications
- pump and compressor shafts
- machine-tool spindles
- belt-driven fan and blower shafts
- automotive and light-truck wheel hubs
Known failure patterns
- false brinelling on idle paired sets exposed to machine vibration
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- rib-roller contact scoring from loss of the EP additive film
- rib-roller contact scoring from loss of the EP additive film
Selection pitfalls — read before you substitute
- O and X arrangements are not interchangeable by turning the set around: 31309T62-5-DB in back-to-back (O) matched pair arrangement has its load-line geometry fixed — specify the arrangement from the shaft thermal and stiffness analysis.
- Spacer faces must stay parallel within the set's own tolerance; a tilted spacer in 31309T62-5-DB concentrates reversing thrust on one bearing and shows up as one-sided raceway wear.
- Replace 31309T62-5-DB as a complete set: pairing a new bearing with a worn partner leaves the clearance undefined even when the designation matches.
- The 194/204 kN ratings are SKF catalogue 17000 values for this execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification.
- Quote the full SKF 31309T62.5/DB designation when purchasing — base-number-only orders are ambiguous across executions and variants.
Frequently asked questions
What are the dimensions and catalogue data of 31309T62-5-DB?
The SKF 31309T62.5/DB is a matched pair of single-row tapered roller bearings in back-to-back (O) matched pair arrangement with 45 mm bore, 100 mm outer diameter and 62.5 mm overall width (1.772 × 3.937 × 2.461 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 194 kN, C0 204 kN, fatigue load limit Pu 24.5 kN, reference speed 4,000 r/min, limiting speed 6,700 r/min, mass about 2.10 kg.
What does the /DB suffix on 31309T62-5-DB mean?
The base 31309T62.5 is the ISO 355 single-row bearing; the /DB suffix marks the matched-set execution — the arrangement (back-to-back (O)), the ground spacer and the factory-set axial clearance class. A matched set cannot be assembled from loose single bearings; quote the full designation when ordering.
Are the C and C0 ratings of 31309T62-5-DB for one bearing or the pair?
They are for the complete matched pair: C 194 kN dynamic and C0 204 kN static already include load sharing between the two bearings. Do not halve them for single-bearing checks, and do not compare them directly with the single-row 31309T62.5 table values.
Can 31309T62-5-DB be adjusted like two loose tapered bearings?
No — the axial clearance is set at the factory by selective spacer grinding. Mounting work is limited to clean seats, correct fits (k5 on a rotating 45 mm shaft) and axial clamping through the cones; re-setting in the field destroys the matched clearance class.
When should a back-to-back (O) matched set be chosen?
Choose the back-to-back (O) set where moment stiffness dominates — pinion supports, gearbox output shafts, crane sheaves. The diverging load lines give the widest effective spread at the 45 mm bore.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.3-8.8 TRB variants on 2026-09-29. Read our editorial & correction policy.