B25Z-28UR 25x66x18mm Automotive Gearbox Bearings

Product Overview

The B25Z-28UR is a non-standard, single-row deep groove ball bearing with a 25.5 mm bore × 66 mm outside diameter × 18 mm width, produced for automotive gearbox and differential applications. Supplier catalogue data identifies it as an automobile gearbox bearing and lists it alongside the related B25Z-28 designation as a transmission/differential bearing. The bearing is manufactured from GCr15 chrome steel, is supplied open (no integral seals), and is available with either a steel or nylon cage depending on the production variant.

Critical dimensional clarification: the catalogue bore is 25.5 mm, not 25 mm

The supplier form states 25 mm bore × 66 mm OD × 18 mm width. The FSK catalogue entry for the B25Z-28UR specifies 25.5 × 66 × 18 mm and a weight of 0.25 kg. A 0.5 mm difference in bore is within the range that can arise from coating thickness, measurement convention, or a variant designation, but it is material for fitment on a gearbox shaft. The supplier must verify the physical stock before publication. If the stock measures 25.5 mm on the bore, the Inside Diameter field should be corrected from 25 to 25.5, and the dimensional string should read 25.5×66×18mm rather than 25×66×18mm. Publishing a 25 mm bore when the standard catalogue value is 25.5 mm risks fitment errors for buyers referencing the B25Z-28UR designation.

Cage material: the catalogue lists both steel and nylon

The supplier form specifies a Nylon Cage. The FSK catalogue entry for the B25Z-28UR lists the cage as steel cage / nylon cage, meaning both configurations exist within the product family. The nylon cage specification in the supplier form is therefore plausible, but the listing should note that steel-cage variants of the same model also exist, and the actual stock should be confirmed before publishing the cage material as definitive.

Weight and performance data

The supplier form leaves Weight, Cr, C0r, and speed ratings blank. The FSK catalogue provides a weight of 0.25 kg for the 25.5 × 66 × 18 mm B25Z-28UR. No accessible public catalogue publishes Cr, C0r, grease speed, or oil speed for this model in its automotive gearbox designation. These fields should remain blank or be marked “Consult supplier” rather than estimated from a generic 25 × 66 × 18 mm deep groove ball bearing, because the non-standard envelope and gearbox-specific internal design make a generic estimate unreliable. This is consistent with the pattern across the preceding vehicle-specific listings: OEM transmission bearings are specified by fitment and assembly position, not by published ISO load ratings.

Key Specifications

Performance Features

• Non-standard gearbox envelope: The 25.5 mm bore × 66 mm OD × 18 mm width is sized to a specific gearbox or differential shaft position where a standard 6205-series bearing would not provide the correct shoulder dimensions or axial spacing.

• Deep groove geometry: The single-row deep groove raceways carry radial loads and accommodate moderate axial loads in both directions, matching the combined load spectrum of a transmission shaft under gear mesh forces.

• GCr15 chrome steel construction: Rings and balls are through-hardened for rolling-contact fatigue resistance under the cyclic loading of automotive gearbox service.

• Nylon cage (per supplier form): The nylon cage provides low-friction ball guidance and is suited to the oil-lubricated environment of a gearbox. The steel-cage variant offers an alternative for higher-temperature or higher-shock duty.

• Open configuration for oil lubrication: No integral seals; the bearing is lubricated by the gearbox oil circuit, consistent with the wet-sump lubrication strategy of a manual or automatic transmission.

Application

The B25Z-28UR is documented as an automobile gearbox bearing and is listed alongside the B25Z-28 designation as a transmission and differential bearing. In service, a bearing of this type supports a gear shaft or differential component under the radial and moderate axial loads generated by the gear train. The 25.5 × 66 × 18 mm envelope and the open, oil-lubricated configuration are consistent with a direct-fit gearbox service bearing. Replacement requires transmission or differential disassembly and should follow the vehicle manufacturer’s procedure for bearing installation and shaft end-play adjustment.

Ordering & Logistics

• Stock: 106 pcs

• Minimum order: 1 pc

• FOB price: US$10 – US$50 per piece

• Payment: PayPal / Western Union / T/T (100% in advance)

• Delivery: 3–4 workdays after payment

• Shipping: DHL / FedEx / UPS / TNT

• Ports: Shanghai / Guangzhou

• Packing: Standard export packing

• Brand: As required (authorized brands only)

• Country of origin: China