798-792 bearing: complete specifications & equivalents
The 798-792 is a ISO 355 radial bearing sized 127 x 206.375 x 47.625 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 127 mm |
| Outer diameter D | 206.375 mm |
| Width B | 47.625 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 424 kN |
| Basic static load rating C0 | 585 kN |
| Fatigue load limit Pu | 61 kN |
| Reference speed (thermal) | 2400 rpm |
| Limiting speed (mechanical) | 3000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6100 g |
| Manufacturer designation | SKF 798/792 |
| Standard | ISO 355 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB |
| Last verified | 2026-09-28 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB) · extracted 2026-09-28
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB); 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 & 795-series range
| Bore d | 5 in |
|---|---|
| Outer diameter D | 8.125 in |
| Width B | 1.875 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 39.7 mm |
| Smallest bore in 795-series | 127 mm |
| Largest outer diameter in 795-series | 206.375 mm |
| Width range across 795-series | 47.625–47.625 mm |
| Bore position in 795-series (smallest first) | 1 of 1 |
| Bore above smallest 795-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 798-792 | Timken | full Dimensions and internal design equivalent — standard interchange. | Same inch-series cone/cup boundary envelope (d/D/T); load ratings and speed limits are brand-specific and may differ. |
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 798-792 model number is decoded
Because the contact line is tapered, one 798 reacts thrust in a single direction; bidirectional shafts need an O or X pair, and a rotating cone on a 127 mm shaft typically takes a m6 seat with an H7 housing bore. Speed envelope and thermal behaviour: at 2,400 r/min thermal reference, the 127 mm bore shaft runs at a dn of 305k, and the 39.7 mm section dissipates heat through the cup-to-housing contact path; the 3,000 r/min mechanical ceiling reflects cage strength, and the 6100 g spinning cone contributes gyroscopic moment under rapid speed reversal. Cup-side note for 792: the outer ring's rib profile and the 206.375 mm outside diameter are cup-specific within the 795-series tables, so substituting a different cup against the same 798 cone changes both the assembled 47.625 mm width and the axial free-play setting of the mounted pair.In SKF catalogue PUB BU/P1 17000, 798 appears as SKF 798/792: an open, single-row tapered roller bearing in the 795-series, supplied with a pressed-steel cage as standard.On the SKF nameplate, 798 denotes a matched cone-and-cup pair: the designation is not a single number but a cone reference and cup reference joined by a slash, with the 795-series marking the dimensional series. The SKF catalogue adds the ISO 355 dimension-series code after the bare number (e.g. ); it is the dimensional series, not a separate part number. Selection arithmetic: the C0/C ratio is about 1.38 (static 585 kN against dynamic 424 kN), typical of a tapered roller sized for axial capacity, and the 61 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation.
Typical equipment & failure modes
Common applications
- marine propulsion gearboxes
- large industrial mixer shafts
- offshore winch and drawworks drums
- large industrial mixer shafts
Known failure patterns
- cup or cone misalignment when the separable rings are not seated square during mounting
- loose cup rotation in the housing when the specified press fit is not achieved
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- axial overload spalling at the roller-rib contact beyond the single-row thrust rating
- pressed-steel cage wear or fracture after prolonged running above the limiting speed
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- At 127 mm bore the cone mass is high enough that cocking during mounting damages the cage and rib; guide the ring square, confirm seat contact around the full circumference, and re-check setting after the first thermal cycle of the paired set.
- The 795-series inch series at 127 mm bore (206.375×47.625 mm) follows the Timken cone/cup convention; substitutions must match both the cone and cup reference exactly — interchanging with another series or a metric 3xxxx bearing of the same bore changes OD, width and contact angle, so re-run the pair setting and shoulder-diameter checks before swapping.
- O (back-to-back) pairs are stiffer against moments, X (face-to-face) pairs tolerate misalignment and thermal growth better; choosing the arrangement from the 2D drawing rather than the actual shaft thermal expansion is a common 798 mounting error.
- The tapered contact angle creates an induced axial load under pure radial force; include it in the 798 rating calculation (and account for it in both bearings of a pair) or the unloaded bearing skids its rollers.
- Open 798 units need application-supplied sealing and a defined EP lubricant supply; the roller-rib contact is the first to fail when the additive film breaks down.
- The 424/585 kN ratings are SKF catalogue 17000 values for the basic 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 and re-verify for critical drives.
- SKF lists several executions of 798 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 798/792 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
How does 798 compare with a ball bearing of the same bore?
A tapered roller bearing has line contact and a steep contact angle: much higher combined axial-plus-radial capacity and shock resistance than a ball bearing of the same bore, at the cost of speed, one-direction thrust, mandatory pairing for reversing loads and a minimum axial load requirement. A ball bearing cannot be dropped into a combined-load 798 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
What shaft and housing fits suit 798?
For a rotating shaft under normal load, seat the cone on a m6 shaft fit; the cup is usually a loose-to-transition fit in the housing so it can creep slightly and distribute wear. Chamfer and shoulder diameters must clear the bearing rings so the 47.625 mm-wide cup seats square; the mounting setting (end play or preload) is set by the axial position of the cup relative to the cone.
Is 798 interchangeable with other brands?
Inch-series tapered roller bearings follow a long-standing industry boundary plan, so cones and cups of the same basic number are generally dimensionally interchangeable across manufacturers. However, internal geometry, cage design and load ratings differ by brand, so for paired or precision applications keep both halves of the set from one manufacturer — or re-verify ratings and setting when mixing.
What are the dimensions and catalogue data of 798?
The SKF 798/792 is a single-row tapered roller bearing with 127 mm bore, 206.375 mm outer diameter and 47.625 mm width (5 × 8.125 × 1.875 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 424 kN, C0 585 kN, fatigue load limit Pu 61 kN, reference speed 2,400 r/min, limiting speed 3,000 r/min, mass about 6100 g. It is an open, separable bearing with a pressed-steel cage.
How does the 798 inch-series designation work?
Inch-series tapered roller bearings use a Timken-style cone/cup convention: the number before the slash identifies the cone (inner ring with roller and cage assembly), the number after the slash identifies the cup (outer ring), and the 795-series code marks the dimensional series. The metric dimensions 127×206.375×47.625 mm are the converted equivalents of the original inch boundary dimensions.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 8.2 inch single-row TRB on 2026-09-28. Read our editorial & correction policy.