MRC5305MFFDouble-Row Angular Contact Ball Bearing, Sealed, 25 x 62 x 25.4 mm, 30 Degree Contact Angle, C3 Clearance

Product Description

What this part is

The MRC 5305MFF is a double-row angular contact ball bearing on the 3305 envelope. Bore: 25 mm. Outside Diameter: 62 mm. Width: 25.4 mm (1 in). Contact Angle: 30°. Internal Clearance: C3. Precision Class: ABEC 1 (normal). Cage Material: Steel. Number of Rows: 2. Unit Quantity: 1 Pc.

Load ratings and speed

Dynamic Load Rating (C): 34,100 N per bearing. Static Load Rating (C0): 30,500 N per bearing. Both are MRC’s published figures for the 5300-M design and both are stated per bearing.

Limiting Speed, grease lubrication (n1): 7,500 rpm. Limiting Speed, oil lubrication (n2): 10,000 rpm. Sealed Speed Rating (n3): 7,500 rpm. The oil figure applies where a circulating or bath oil system carries heat out of the bearing; the grease figure applies to a closed, grease-packed bearing.

Maximum Abutment Fillet Radius (ra): 1.00 mm. This is the largest fillet permitted on the mating shaft and housing shoulders.

Why a double-row angular contact instead of two single bearings:
The two ball rows sit on a single one-piece inner ring and a single one-piece outer ring, effectively a back-to-back pair built into one part. That gives radial capacity plus thrust capacity in both directions, and enough moment stiffness to hold a shaft square, all inside one bearing width. It replaces a duplex pair in less axial space and with a fixed factory relationship between the two rows.

The 30° contact angle is brand-specific. MRC’s 5300 series runs 30°, while the Fafnir/Timken 5300 series on the same 25 x 62 x 25.4 mm envelope runs 20°. A steeper angle carries more thrust and more axial stiffness, at the cost of a lower speed ceiling and less radial capacity. A Fafnir 5305K and this MRC 5305MFF share housing and shaft dimensions and differ in duty.

Decoding the designation

5305 — double-row angular contact, medium series, bore code 05 = 25 mm bore.

M — the 5300-M design generation, which carries its own load ratings and speed ratings, separate from those of the 5300-C design.

FF — closed on both faces, MRC’s double-closure form.

C3 — internal clearance greater than normal. C3 suits a bearing whose inner ring runs hotter than its outer ring, and an interference fit that would otherwise take running clearance out of the bearing.

Quantity and configuration

Sold as one bearing. Unit Quantity: 1 Pc.

Interchange guidance

MRC (Marlin Rockwell) is part of SKF, so current replacements cross to SKF numbering. Related MRC family members on the same envelope include 5305C, 5305CF, 5305CFF, 5305CG, 5305CFFG, 5305MF and 5305MG; the trailing G adds a snap ring in the outer ring. The 5300-C members carry different load and speed ratings from this 5300-M part, so they are related articles rather than rating-for-rating equivalents. The ISO cross-reference for the envelope is 3305. Also written 5305-M-FF, 5305 MFF and MRC5305MFF.