Pagid U2126 Brake Pads for AP RADI-CAL 5000R and Brembo XC0Z8 Brake Calipers
 
The Pagid U2126 racing brake pad is a direct-fit friction solution for the AP Racing Radi-CAL 5000R 4-piston caliper and the Brembo XC0Z8 4-piston caliper. Manufactured by PAGID Racing — the exclusive motorsport brand of the TMD Friction Group and an OE friction supplier to marques like Porsche and Ferrari — the U2126 shape is offered here in four proven compounds, letting you match friction level, wear rate, and temperature behavior to your discipline, whether that's endurance racing, sprint racing, rally, or club-level competition.
 
Every Pagid Racing compound is engineered to balance friction level, fade resistance, disc wear, and modulation, with low heat conductivity that limits heat transfer into the caliper and brake fluid. All four compounds below are designed for iron/steel rotors.
 
Fitment
 
AP Racing Radi-CAL 5000R 4-piston brake caliper
Brembo XC0Z8 brake caliper
Pad shape: Pagid U2126
Sold as a caliper set
 
Choosing Your Compound
 
Pagid RSL1 – High Friction Endurance (Yellow / RSL Family) The endurance benchmark. RSL1 is a low-metallic, resin-bonded material with steel and aramid fibers and very high heat resistance. It holds a constant friction level across a wide temperature window, with a low wear rate and excellent disc friendliness — the reasons it has racked up wins at Le Mans, Daytona, Sebring, Spa, and the Nürburgring. Best used as a front pad on GT, touring, and prototype cars in endurance racing, though its high friction and strong modulation make it a frequent choice in sprint racing as well.
 
Pagid RSL29 – Medium Friction Endurance (Yellow / RSL Family) The most versatile compound in the lineup and arguably the most famous endurance pad in motorsport. RSL29 offers a constant low-to-medium friction level with outstanding modulation and release characteristics, easy bed-in behavior, and fade resistance to roughly 650°C (1,200°F). Its good cold performance, long pad and disc life, and ABS-friendly release have also made it a favorite for club racing and track days. If you're not sure where to start, start here.
 
Pagid RST1 – Very High Friction Sprint (RST Family) Maximum torque. RST1 is a semi-metallic, resin-bonded compound with steel fibers, delivering a very high friction level with strong cold bite and high temperature resistance. It's built for tarmac rally, NASCAR-style stock car racing, high-downforce formula cars, and sprint-format GT/touring competition — and it's the go-to choice for heavy cars or any application where high brake torque must be generated against smaller-diameter rotors.
 
Pagid RST3 – Medium-High Friction All-Rounder (RST Family) The flexible one. RST3 is a metal-ceramic compound with steel fibers and notably low heat conductivity, which helps keep heat out of the caliper and fluid. It combines strong initial bite with a medium-high friction level and excellent controllability, and its clean release characteristics make it particularly well suited to cars running ABS. Applications span tarmac and gravel rally, GT, touring, and prototype circuit racing, formula cars, and club racing.
 
Bedding In
Pagid Racing pads require proper bedding to reach full friction performance and avoid judder or vibration. Follow Pagid's published bed-in procedure before competition use. Some squeal is normal behavior for racing compounds.