Wilwood Left Black GTB Spec-37 Rotor, 15.00 x 1.25-inch with 72 Curved Vanes

This black-finished left rotor uses the GT slot pattern on a heavy-wall Spec-37 casting. The 15.00 x 1.25-inch envelope is combined with the twelve-on-8.75-inch hat interface, with no hub or mounting hardware included. Based in Camarillo, California, Wilwood Engineering was founded in 1977 by Bill Wood to design and manufacture disc brake systems and components. Its calipers, brake rotors, master cylinders, valves, fittings and brake lines serve motorsport, street-performance and specialized applications. Rotor selection is therefore a decision about the whole brake system and its mating parts.

Technical Details

• Manufacturer part number: 160-14634-GTB
• Rotor size: 15.00 inches diameter x 1.25 inches wide
• Rotor material: Spec-37 Iron
• Face and finish: GT Slotted; Black electrocoat
• Vanes: 72 CV; curved
• Mounting direction: Left-hand
• Factory condition: Factory burnished no; balanced yes
• Opposite-side component, ordered separately: 160-14633-GTB
• Rotor-to-hat/hub attachment circle: 12 x 8.75 inches
• Attachment hole size or thread: 0.251 inches
• Center / lug registration: 8.25 inches
• Far-side inside diameter: 9.65 inches
• Approximate component weight: 26.10 lb
• Quantity: one rotor ring; hat, hub, mounting hardware, calipers and pads are separate

Fitment & Compatibility

This left GTB ring requires the twelve-on-8.75-inch attachment and an 8.25-inch centering register, despite its larger fifteen-inch outside diameter. Check clearance around the complete caliper and ensure the pad sweep stays within the intended friction band. The black finish is separate from the Spec-37 iron material.

Manufacturer reference: Wilwood rotor specifications

Contact PMB Performance with the rotor and brake-system details for fitment assistance informed by more than 20 years of experience.