33220T135-DB bearing: complete specifications & equivalents
The 33220T135-DB is a ISO 355 radial bearing sized 100 x 180 x 135 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 180 mm |
| Width B | 135 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 912 kN |
| Basic static load rating C0 | 1320 kN |
| Fatigue load limit Pu | 140 kN |
| Reference speed (thermal) | 2400 rpm |
| Limiting speed (mechanical) | 3600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 14000 g |
| Manufacturer designation | SKF 33220T135/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 | 3.937 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 5.315 in |
| ISO bore code | 35 |
| Radial section height (D−d)/2 | 40 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) | 14 of 30 |
| Bore above smallest matched-db-series size | 65 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33220T135 | 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 33220T135-DB model number is decoded
Lubrication for the pair should be sized against the combined 135 mm width and 14000 g mass: two roller sets sweep twice the contact area of a single bearing of the same bore.For a 100 mm shaft carrying reversing axial load, SKF lists 33220T135-DB under catalogue execution SKF 33220T135/DB: a factory-matched back-to-back (O) matched pair tapered-roller pair, set and measured as one unit.On the SKF nameplate, 33220T135-DB reads as base 33220T135 in a /DB matched execution — the suffix is part of the order number because a matched set is ground for a specific axial clearance and cannot be assembled from loose single bearings. Back-to-back matching puts the large rib ends outward — the stiffest arrangement for moment load, but one that converts shaft thermal growth into preload change; the factory setting of 33220T135-DB already accounts for the expected temperature gradient across the 135 mm pair width. Speed planning for the set uses the catalogue pair values: 2,400 r/min thermal reference and 3,600 r/min mechanical limiting speed — a matched pair runs warmer than one bearing because two roller sets share the 135 mm space. Cross-section geometry: the 40.0 mm half-section ((180−100)/2) places the roller pitch diameter near 140 mm, and the 135 mm axial width sets the abutment depth — geometry that fixes the contact angle behaviour of 33220T135-DB. Mounting order matters for 33220T135-DB: seat the first bearing, fit the ground spacer, then the second bearing, and clamp axially as a unit — the 135 mm catalogue width is the assembled result and the gauge for correct assembly.
Typical equipment & failure modes
Common applications
- paper-machine and printing rolls
- construction machinery drives
- marine deck machinery shafts
- rolling-mill auxiliary drives
Known failure patterns
- false brinelling on idle paired sets exposed to machine vibration
- preload loss as the mounted pair relaxes, letting rollers skid and smear the raceways
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- hard-particle indentation of the tapered raceway in unfiltered oil
- 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: 33220T135-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.
- Setting is built into 33220T135-DB; the classic field error is re-adjusting a matched pair as if it were two loose single bearings, which destroys the /DB clearance class.
- Replace 33220T135-DB as a complete set: pairing a new bearing with a worn partner leaves the clearance undefined even when the designation matches.
- The 912/1320 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 33220T135/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 33220T135-DB?
The SKF 33220T135/DB is a matched pair of single-row tapered roller bearings in back-to-back (O) matched pair arrangement with 100 mm bore, 180 mm outer diameter and 135 mm overall width (3.937 × 7.087 × 5.315 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 912 kN, C0 1320 kN, fatigue load limit Pu 140 kN, reference speed 2,400 r/min, limiting speed 3,600 r/min, mass about 14.00 kg.
What does the /DB suffix on 33220T135-DB mean?
The base 33220T135 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 33220T135-DB for one bearing or the pair?
They are for the complete matched pair: C 912 kN dynamic and C0 1320 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 33220T135 table values.
Can 33220T135-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 100 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 100 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.