Fafnir7405Angular Contact Ball Bearing – Straight Bore, 25mm ID, 80mm OD, 21mm Width, Open, 40° Contact Angle (MRC 7000 Series).

Product Description

What this part is

MRC 7405 single-row angular contact ball bearing, 25 mm bore, 80 mm outside diameter, 21 mm width. Straight bore, open on both faces, pressed brass cage.

Decoding the designation

The 7400 series is the extra-heavy angular contact dimension series, which is why a 25 mm bore carries an 80 mm outside diameter here where a 7205 of the same bore measures 52 mm. The bore code 05 denotes 25 mm, the bore code multiplied by five. The MRC 7000 series is built to a 29° contact angle. In the MRC scheme the suffix D marks a matched duplex assembly, and the MRC catalogue lists 7405-D at 42 mm assembly width, the stacked width of two 21 mm bearings.

What these specs mean in practice

A single-row angular contact bearing carries thrust in one direction only, and the ring faces are marked high and low shoulder accordingly. A 29° angle sits between the 15° and 40° standards: more axial capacity than a 15°, more speed capability than a 40°. The extra-heavy section gives 64.5 kN dynamic and 47.1 kN static capacity at a 25 mm bore, with a grease limiting speed of 8000 rpm.

Cage and precision

Pressed brass cage, ABEC 3 running accuracy, equivalent to ISO P6. Brass tolerates higher temperature and marginal lubrication better than a polyamide cage.

Quantity and configuration

One piece, one bearing, 21 mm wide.

Fitting notes

Thrust is taken on the high-shoulder side, so orientation is set by the direction of axial load. Where two are mounted back to back or face to face, both are seated firmly against their abutments before the locknut is drawn up.

Interchange guidance

The FAG 7405-B shares the 25 x 80 x 21 mm envelope at a 40° contact angle, so it is a related size rather than a direct equivalent: the angle changes the thrust and speed rating. A direct equivalent is a 7405 built to a 29° angle. The MRC 7405-D is the matched pair of the same bearing, 42 mm across the assembly.