Best 108mm brake calipers

Top pick: Brembo M4 Monobloc Radial Caliper 108mm. It's the one to start with — a monobloc four-piston radial caliper on the 108mm bolt spacing, which is the standard upgrade for a serious front brake on a sport or track bike. Monobloc bodies flex less under hard braking, so you get a firmer lever and more consistent feel than a two-piece caliper.

Who the others suit:

• Brembo GP4-RX Radial Mount Caliper 108mm — for racers and dedicated track builds. It's the more exotic, machined two-piece body with multi-pitch mounting (108/100/130mm), so it also fits more fork lugs. Overkill for a street bike.
• MOSTPLUS caliper sets — for a stock replacement on a car (e.g. the Ford Focus set), not a 108mm radial motorcycle upgrade.
• Raybestos FRC11909 — a semi-loaded OE-style car caliper, for a daily driver repair.

Before buying, measure the bolt spacing on your fork lugs and check piston sizes and brake line fittings — 108mm is a common pitch but not universal.