Absolute Control: Performance Machine 4-Piston Rear Caliper Kit (1987–1999 Softail)

Bring your 1980s or 90s Softail into the modern era with the Performance Machine (PM) 4-Piston Differential-Bore Rear Caliper. Factory rear brakes on Evolution Softails are often criticized for their “mushy” feel and lack of initial bite. PM solves this with a race-inspired, high-pressure system that provides the confidence-inspiring braking performance required for today’s roads.
The Science of Differential-Bore Engineering

The “Differential Bore” design is what separates Performance Machine from standard aftermarket calipers:

Balanced Pressure: By using staggered piston sizes (two small leading pistons and two larger trailing pistons), PM ensures that the brake pad makes perfectly even contact with the rotor.

Consistent Wear: This staggered pressure prevents “tapered” pad wear, extending the life of your brake pads and ensuring that the “bite” feels exactly the same from the first mile to the last.

Superior Clamping: The 4-piston design offers significantly more surface area and hydraulic pressure than the stock single-piston setup, drastically reducing stopping distances.

Dedicated Fitment for Evolution Softails

Unlike universal “weld-on” kits, this is a precision-engineered, bolt-on solution:

Integrated Bracket: The kit includes a dedicated mounting bracket designed to fit the 3/4″ rear axle and swingarm geometry of 1987–1999 Softail models (FXST and FLST).

Rotor Compatibility: Optimized for use with the standard 11.5″ rear rotor.

Billet Rigidity: CNC-machined from a solid block of 6061-T6 aluminum, the caliper body is far more rigid than cast factory units. This stiffness translates every ounce of pedal pressure directly into deceleration, eliminating the “flex” and “fade” common in older bikes.

Performance Machine Signature Style

Custom Finishes: Available in show-quality Chrome, the modern Contrast Cut (black anodized with machined accents), or the stealthy Black Ops (textured matte black).

Complete Package: The assembly comes pre-loaded with high-friction brake pads and includes all necessary mounting hardware and a bleeder screw.

Low Maintenance: Engineered with high-grade internal seals and stainless steel pistons for long-term reliability in all weather conditions.

Stop guessing when your bike will stop. Upgrade to the Performance Machine Rear Caliper Kit and enjoy the perfect marriage of classic Softail style and world-class braking performance.

This Product Fits

Harley Davidson
Softail Custom FXSTC/I 1987-1999
Softail Fat Boy FLSTF/I 1990-1999
Softail Heritage Classic FLSTC/I 1987-1999
Softail Heritage FLST/I 1987, 1988, 1989, 1990
Softail Nostalgia FLSTN/I 1993
Softail Special FLSTN/I 1994, 1995, 1996
Softail Standard FXST/I 1987, 1988, 1989, 1990, 1999