3490-3420 bearing: complete specifications & equivalents
The 3490-3420 is a ISO 355 radial bearing sized 38.1 x 79.375 x 29.37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 38.1 mm |
| Outer diameter D | 79.375 mm |
| Width B | 29.37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 112 kN |
| Basic static load rating C0 | 110 kN |
| Fatigue load limit Pu | 12.5 kN |
| Reference speed (thermal) | 7000 rpm |
| Limiting speed (mechanical) | 8500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 680 g |
| Manufacturer designation | SKF 3490/3420 |
| 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 & 3400-series range
| Bore d | 1.5 in |
|---|---|
| Outer diameter D | 3.125 in |
| Width B | 1.156 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 20.6 mm |
| Smallest bore in 3400-series | 38.1 mm |
| Largest outer diameter in 3400-series | 79.375 mm |
| Width range across 3400-series | 29.37–29.37 mm |
| Bore position in 3400-series (smallest first) | 1 of 1 |
| Bore above smallest 3400-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3490-3420-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 3490-3420 | 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 3490-3420 model number is decoded
Journal and housing interface: the 38.1 mm bore takes a k5 shaft seat (upper deviation ~0.076 mm for this diameter range) and the 79.375 mm outside diameter pairs with an H7 housing bore tolerance band of 79.375.000/79.395 mm; the 29.37 mm width defines the shoulder depth, and the 680 g cone-plus-cup assembly is the dead load on the shaft during thermal expansion calculations. Cone versus cup responsibility in 3490: the 3490 cone carries the 38.1 mm bore, rollers and pressed-steel cage; the 3420 cup carries the 79.375 mm OD raceway, the roller-seating rib and the outer press-fit surface. The two references are not interchangeable halves.Ordering number SKF 3490/3420 in SKF catalogue PUB BU/P1 17000 denotes a single-row tapered roller bearing for a 38.1 mm shaft, inch series, with an open pressed-steel-cage execution and one-direction axial capacity.The 3400-series series assigns 38.1 mm bore, 79.375 mm OD and 29.37 mm width to 3490; the cone and cup references are not interchangeable with other inch-series pairs even when the bore matches, because the cup profile and rib geometry are series-specific. 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. The 20.6 mm radial section height ((79.375−38.1)/2) and 680 g catalogue mass frame a 38.1 mm bore bearing rated at 112 kN C — roughly 2.94 kN of dynamic capacity per millimetre of bore before application factors. A single 3490 locates the shaft in one axial direction only; mount it against a second bearing in O (back-to-back) or X (face-to-face) arrangement, and set the running clearance by the mounting procedure — not by feel.
Typical equipment & failure modes
Common applications
- machine-tool spindles
- belt-driven fan and blower shafts
- axle-boxes in material-handling equipment
- automotive and light-truck wheel hubs
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
- 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
- mounting score marks when the cone is cocked over the shaft keyway or a burr
Selection pitfalls — read before you substitute
- On this 38.1 mm bore, interference and temperature rise consume clearance inside a preloaded pair; calculate the residual clearance after mounting and at operating temperature — an over-tight 3490 pair heats, loses setting control and smears the roller-rib contact.
- The 320 series at 38.1 mm bore (79.375×29.37 mm) is the low-friction, higher-speed section; it carries less thrust than a 302 of the same bore, so verify the axial load share before swapping.
- A single 3490 cannot locate the shaft axially in both directions; mounting it singly on a reversing-thrust shaft leaves one direction uncontrolled — always use an O or X matched pair for bidirectional location.
- When the outer ring rotates, reverse the fit logic and provide cup location; the tapered contact of 3490 pushes the rings apart under load, so a non-located cup walks its seat even when the shaft is fixed.
- The 680 g mass and 29.37 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 3490.
- The 112/110 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 3490 (basic, B steeper angle, Q/J2 clearance variants); they are not interchangeable order numbers — quote the full SKF 3490/3420 designation when purchasing and match the execution to the mounting arrangement.
Frequently asked questions
What shaft and housing fits suit 3490?
For a rotating shaft under normal load, seat the cone on a k5 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 29.37 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 3490 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 3490?
The SKF 3490/3420 is a single-row tapered roller bearing with 38.1 mm bore, 79.375 mm outer diameter and 29.37 mm width (1.5 × 3.125 × 1.156 in). From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 112 kN, C0 110 kN, fatigue load limit Pu 12.5 kN, reference speed 7,000 r/min, limiting speed 8,500 r/min, mass about 680 g. It is an open, separable bearing with a pressed-steel cage.
How does the 3490 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 3400-series code marks the dimensional series. The metric dimensions 38.1×79.375×29.37 mm are the converted equivalents of the original inch boundary dimensions.
What do the cone and cup numbers in 3490 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 (3400-series) groups sizes that share the same boundary-dimension plan.
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.