Timken5305KGDouble Row Angular Contact Ball Bearing, 25 x 62 x 25.4 mm, 20° Contact Angle, 37.7 kN Dynamic

Product Description

What this part is

A Timken Fafnir double row angular contact ball bearing in the 5300 medium series: 25 mm bore, 62 mm outside diameter, 25.4 mm wide. Two rows of balls run on angled raceways inside a single pair of rings. That construction gives it the one property a deep groove ball bearing cannot match at the same envelope — substantial thrust capacity in both directions from one bearing, with no need to set preload against a second bearing at assembly.

It is the answer to a specific design problem: a shaft that has to be located axially in both directions but has no room for two opposed single-row bearings and no provision for a shim stack or setting nut. Pumps, blower and fan shafts, worm gear inputs, agricultural gearboxes and light machine spindles are where these turn up.

The 20° contact angle — and why the brand on the ring matters here:
Timken publishes the contact angle for the 5305KG as 20°. This is the single most important number on the page and it is brand-specific, not a property of the 5305 designation. MRC’s 5305MG and 5305CG at the same 25 mm bore and 62 mm outside diameter are 30° bearings. Same nominal part number, same envelope, half again the contact angle.

What changes with the angle is the trade between thrust capacity and speed. A larger contact angle steers more of the load into the axial direction, raising thrust capacity and axial stiffness but increasing ball spin and heat generation, which lowers the practical speed limit. A 20° bearing is the more radial, faster-running, lower-heat option; a 30° bearing takes more thrust and is stiffer axially. Neither is better — they are different bearings.

The consequence for a buyer is direct: a machine drawing specifying a 30° double-row angular contact bearing is asking for a different axial capacity than this 20° Timken unit provides, even though the digits match. Check the angle, not just the digits. Where a rebuild is failing on thrust and the previous bearing was replaced like for like across brands, this is a very common root cause.

Published ratings and mounting data

All figures below are from Timken’s own catalogue entry for 5305KG.

Bore (d): 25 mm.

Outside diameter (D): 62 mm / 2.4409 in.

Width (C): 25.4 mm / 1.000 in.

Contact angle: 20°.

Dynamic radial load rating C1 (1 x 10^6 rev): 37,700 N / 8,500 lbf.

Static radial load rating C0: 21,100 N / 4,750 lbf.

Ball material: steel.

Cage type: snap-in.

Number of rows: 2.

Maximum shaft fillet radius: 1 mm / 0.039 in.

Shaft backing shoulder diameter: 31.120 mm / 1.225 in.

Housing backing shoulder diameter: 54.100 mm / 2.130 in.

Outer ring to-clear radius (r): 1 mm / 0.039 in.

Why the backing shoulder diameters are on this page:
Because nobody publishes them and they decide whether a rebuild works. The shaft backing shoulder must be at least 31.120 mm in diameter to support the inner ring across its full face, and the housing backing shoulder no more than 54.100 mm so it bears on the outer ring and not on the inner. A shoulder outside those figures loads the wrong ring, which on a double row angular contact bearing means loading it through the balls, and that is how a new bearing acquires brinell marks during installation. The same applies to the 1 mm maximum fillet radius: a more generous radius on a shaft step holds the inner ring off its seat, tilts it, and puts the two ball rows out of alignment with each other.

The 3305 NR cross-reference

This record also carries the designation 3305 NR. The 3300 and 5300 series describe the same double row angular contact envelope under different numbering conventions, and NR conventionally denotes a snap-ring groove and snap ring in the outer ring. The Timken catalogue entry for 5305KG lists the cage as snap-in type, which is a cage feature and a different thing from an external snap ring. 3305 NR is carried here as a designation buyers search on.

Quantity and configuration

One complete bearing. A double row angular contact unit locates the shaft in both directions on its own, so this single bearing does the job that two opposed single-row bearings would. Its internal geometry is set at manufacture, so there is no endplay or preload to establish at assembly. This is the standard build without an external snap ring.

Interchange guidance

Search forms include 5305KG, 5305-KG, 5305 KG, 5305K, 5305, 3305, 3305NR and 3305 NR. Timken absorbed the Fafnir bearing line, so machinery originally specified with Fafnir 5300-series bearings is supported by Timken part numbers today. Same-envelope equivalents are catalogued by MRC (now SKF) as 5305MG and 5305CG, by NSK as 5305, by NTN as 5305 and by Nachi as 5305, all at 25 × 62 × 25.4 mm. Verify the contact angle before treating any of them as a drop-in for this one.