M336948-912 bearing: complete specifications & equivalents
The M336948-912 is a ISO 355 radial bearing sized 178.595 x 265.112 x 51.595 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 178.595 mm |
| Outer diameter D | 265.112 mm |
| Width B | 51.595 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 532 kN |
| Basic static load rating C0 | 880 kN |
| Fatigue load limit Pu | 85 kN |
| Reference speed (thermal) | 1800 rpm |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 9550 g |
| Manufacturer designation | SKF M 336948/912 |
| 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 & M336900-series range
| Bore d | 7.031 in |
|---|---|
| Outer diameter D | 10.437 in |
| Width B | 2.031 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 43.3 mm |
| Smallest bore in M336900-series | 178.595 mm |
| Largest outer diameter in M336900-series | 265.112 mm |
| Width range across M336900-series | 51.595–51.595 mm |
| Bore position in M336900-series (smallest first) | 1 of 2 |
| Bore above smallest M336900-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| M336948-912 | 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 M336948-912 model number is decoded
For a 178.595 mm shaft carrying combined load, SKF lists M336948 under catalogue execution SKF M 336948/912: one open single-row tapered roller bearing in the inch M336900-series.On the SKF nameplate, M336948 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 M336900-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 1.65 (static 880 kN against dynamic 532 kN), typical of a tapered roller sized for axial capacity, and the 85 kN fatigue load limit Pu is the equivalent-load floor used in the life calculation. Specify pairs rather than single units wherever thrust reverses: the tapered contact of M336948 generates an induced axial load under radial force, and an unpaired bearing on a reversing shaft will run slack and fret its seat. Journal and housing interface: the 178.595 mm bore takes a m6 shaft seat (upper deviation ~0.357 mm for this diameter range) and the 265.112 mm outside diameter pairs with an H7 housing bore tolerance band of 265.112.000/265.132 mm; the 51.595 mm width defines the shoulder depth, and the 9550 g cone-plus-cup assembly is the dead load on the shaft during thermal expansion calculations. A single-row inch tapered bearing is quoted as a cone/cup pair because the boundary dimensions belong to the combination, not to either half alone: in M336948 the M 336948 cone contributes the 178.595 mm bore and roller set, the 912 cup contributes the 265.112 mm OD raceway, and the assembled 51.595 mm width is the catalogue value.
Typical equipment & failure modes
Common applications
- heavy-duty rolling-mill gearboxes
- large crusher and mineral-processing drives
- wind-turbine main shafts
- heavy-duty rolling-mill gearboxes
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
- thermal preload runaway in an O-arrangement pair when inner-ring heat expands the setting
- uneven load sharing in a pair when spacer faces are not parallel to the bore
- cage pocket scoring when the bearing starts cold with grease of too-high base-oil viscosity
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- At 178.595 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 M336900-series inch series at 178.595 mm bore (265.112×51.595 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.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of M336948 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of M336948 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- The 9550 g mass and 51.595 mm width mean spacer and abutment faces must be square to the axis within the bearing's own P0 tolerance; a tilted spacer tilts the contact angle and concentrates load on one rib of M336948.
- The 532/880 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 M336948 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF M 336948/912 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What are the dimensions and catalogue data of M336948?
The SKF M 336948/912 is a single-row tapered roller bearing with 178.595 mm bore, 265.112 mm outer diameter and 51.595 mm width (7.031 × 10.437 × 2.031 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 532 kN, C0 880 kN, fatigue load limit Pu 85 kN, reference speed 1,800 r/min, limiting speed 2,200 r/min, mass about 9550 g. It is an open, separable bearing with a pressed-steel cage.
How does the M336948 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 M336900-series code marks the dimensional series. The metric dimensions 178.595×265.112×51.595 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in M336948 mean?
The cone number (before the slash) identifies the inner ring, rollers and cage; the cup number (after the slash) identifies the outer ring. Both are quoted together because a single-row tapered roller bearing is a matched separable pair — the cone and cup are ground to work together and are not interchangeable with arbitrary other parts. The series prefix (M336900-series) groups sizes that share the same boundary-dimension plan.
Can a single M336948 take axial load in both directions?
No — one single-row tapered roller bearing reacts thrust in one direction only, and under radial load its contact angle induces an axial force. Use two bearings as a matched pair: O (back-to-back) for a rigid, moment-resisting arrangement, X (face-to-face) where thermal expansion must be tolerated, or tandem where one-direction thrust is shared.
How does M336948 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 M336948 position and vice versa — verify load direction, Fa/Fr ratio and speed before substituting.
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.