128602 Automotive Motorcycle Steering Bearings 20x48x13.5mm

Product Overview

The 128602 is a single-row angular contact ball bearing with boundary dimensions of 20 mm bore × 48 mm outside diameter × 13.5 mm width, specified for motorcycle and automotive steering applications. The angular contact geometry is configured to support combined radial and axial loads simultaneously—a requirement at the steering head, where the bearing must carry the vertical load of the front end while accommodating the axial forces generated during steering and braking. The bearing is supplied open (unsealed) for grease lubrication, uses a nylon cage with GCr15 chrome steel balls, and is rated to P0 precision with C3 internal clearance.

This is a non-standard bearing: the 20 × 48 × 13.5 mm envelope and the 128602 designation do not correspond to a standard ISO metric angular contact ball bearing series. It is a vehicle-specific steering-head component, and its internal geometry (contact angle, ball complement, raceway conformity) is set by the original equipment specification rather than by a general-purpose catalogue.

Key Specifications

Performance Features

• Angular contact geometry for combined loading: The raceway offset produces a contact angle that enables the bearing to carry axial loads in one direction together with radial loads—the load combination present at a motorcycle steering head during cornering, braking, and road input.

• Nylon cage: The nylon cage provides low-friction ball guidance and is suited to the grease-lubricated, oscillating service of a steering bearing, where the bearing does not complete continuous revolutions but rocks through small angles.

• GCr15 chrome steel balls and rings: Through-hardened GCr15 provides the rolling-contact fatigue resistance required for the cyclic loading of steering service.

• C3 internal clearance: The greater-than-normal clearance accommodates the interference fits used when pressing the bearing into the steering head and onto the stem, and provides margin for thermal variation in the steering assembly.

• Open configuration: The bearing is packed with grease during steering-head assembly; the open design allows the grease to be applied directly to the ball and raceway surfaces, and permits periodic relubrication where the steering column design provides access.

• Vehicle-specific envelope: The 20 mm bore and 48 mm outside diameter are sized to the steering stem and head tube of specific motorcycle models, making the 128602 a direct-fit replacement rather than a generic catalogue bearing.

Application

The 128602 is used as a motorcycle steering head bearing, installed in the steering column to support the triple clamp / steering stem assembly. In service, it operates as part of a two-bearing set (upper and lower steering head positions), with the pair sharing the radial and axial loads of the front end. The bearing’s application environment is grease-lubricated and exposed to road contaminants, and steering-head preload is adjusted during installation to remove free play while allowing smooth, low-friction steering rotation. Because this is a vehicle-specific non-standard bearing, correct fitment depends on matching the 20 × 48 × 13.5 mm envelope to the motorcycle model’s steering stem and head tube dimensions.

Ordering & Logistics

• Stock: 66 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

• OEM service: Available

• Brand: As required (authorized brands only)

• Country of origin: China

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