Wilwood 120-13949 Grand National GN6R 6-Piston Radial Mount Disc Brake Caliper Left Hand Hard Anodized

The Wilwood Grand National GN6R (120-13949) is a six-piston radial mount brake caliper engineered for extreme competition demands. This left-hand caliper features a high-strength forged aluminum body with a durable hard-anodized finish, designed to deliver consistent, fade-resistant stopping power in sustained high-heat environments.

Each GN6R body is stress-flow forged from premium-grade aluminum alloy, a process that re-aligns the metal's internal grain structure to follow the contour of the caliper body — producing a stronger, lighter component than conventional casting methods. The result is a caliper built to handle the punishment of short track, road course, and off-road competition.

Key Features:

• Six-piston differential bore configuration — 1.75" / 1.38" / 1.38" piston bore sizes provide balanced clamping load for even pad wear under sustained heat
• One-piece stainless steel pistons — selected for low heat transfer and high corrosion resistance
• Radial mount design — simplifies installation and provides two planes of adjustment for precise rotor alignment
• Hard-anodized finish — corrosion-resistant and durable for race and performance applications
• Bolt-in center bridge — allows quick, easy brake pad access and changes
• Compatible rotor thickness: 1.25" – 1.38" (31.75mm – 35mm)
• Compatible rotor diameter: 12.19" – 13.06" (309mm – 331.7mm)
• Pad body width: .80" (20.3mm)
• Mount: Left-hand radial mount
• Compatible with 3.50" or 6.00" center lug mount radial bracket kits — direct replacement for all previous Grand National caliper models

The GN6R is sold individually. Use with Wilwood radial mount bracket kits for a bolt-in upgrade or replacement of 3.50" or 6.00" center lug mount Grand National calipers.