Road brake pads

When the friction material thickness falls below 0.5 mm, visible on visual inspection without removing the caliper. New pads generally have 3 to 4 mm of friction material. By removing the wheel and looking at the caliper from the side, you can see the pads on both sides of the disc. Shimano and SRAM specify a minimum thickness of 0.5 mm for their pads. Before reaching this limit, a warning sign appears: the brake lever starts to move closer to the handlebars (the automatic adjustment mechanism can no longer compensate for the wear). A high-pitched metallic screech is the final warning: the metal pads are touching the disc.

No, the shape of the pad is specific to each caliper. Shimano, SRAM, Campagnolo, Magura and TRP each have their own pad profiles. Third-party brands (Galfer, Swissstop, Kool Stop) manufacture compatible pads, explicitly stating the calipers they are compatible with. For Shimano road brakes (Dura-Ace R9270, Ultegra R8170, GRX), check the pad code (L04C, L05A...) on the caliper or in the documentation. For SRAM AXS (Red, Force, Rival), the pads are the same across the different tiers of the SRAM AXS road range.

30 to 50 gradual braking actions on a gentle incline or decline, allowing the brakes to cool between sets. Running-in is essential to transfer a uniform layer of friction material onto the disc (glazing) and to mould the new pads to the disc’s surface. Procedure: on a gently descending road, alternate 10 moderate braking actions from 40 to 15 km/h, allow to cool for 2–3 minutes, repeat 3 to 5 times. A new, unbroken-in set may produce uneven or noisy braking. Avoid any hard braking during the first 50 km after a change.

Centre the caliper, run in the pads and clean the discs: these three steps resolve 95% of squeaking noises. Squeaking can have several causes: a misaligned caliper (constant rubbing), unbeddied pads, a disc contaminated with grease or oil, or pads that have become vitrified (glazed) due to overheating. Diagnosis: if the squeaking is present when the wheel is stationary (without braking), the caliper is rubbing: realign it. If the squeaking only occurs when braking: clean the discs with alcohol and, if the problem persists, lightly sand the pads with P120 sandpaper and run them in again.

No, the pad profiles are different and incompatible between road and MTB. Flat Mount road calipers have a specific (more compact) pad format that differs from Post Mount or IS MTB calipers. Even if a road and MTB caliper were from the same brand (e.g. two Shimano hydraulics), the pads are not interchangeable. The only reliable way to check is to look at the pad code marked on the caliper or in the manufacturer’s technical documentation.

They are recognised as being better for wet conditions and long descents; the original Shimano pads are excellent for normal use. SwissStop (a Swiss brand) is renowned for its Black Prince (carbon) pads for carbon rims and its Flash Pro (road disc) pads, which offer exceptional bite in the rain and greater durability than the original pads. Galfer offers sintered pads that are more heat-resistant. The original Shimano pads (L04C, L05A) are of excellent quality and are sufficient for 90% of cyclists. Replacing them with premium pads is justified for competitive cyclists who regularly tackle long descents.

Shimano uses mineral oil (Shimano Mineral Oil only); SRAM uses DOT 5.1 fluid. These two fluids are incompatible: never mix mineral oil and DOT. Shimano mineral oil is less harsh on seals and cables than DOT, but does not withstand extreme temperatures as well. The DOT 5.1 used by SRAM withstands higher temperatures, which is useful for long descents. Campagnolo uses DOT 11 (brand-specific). A system contaminated with the wrong fluid can cause seals to swell and result in a total loss of braking power.

Every 2 years under normal use, or as soon as a lever feels spongy or comes too close to the handlebars. Brake fluid absorbs moisture over time (it is hygroscopic, especially DOT fluid), which lowers its boiling point and can cause air bubbles to form during heavy braking. Shimano mineral oil is less hygroscopic but also degrades with thermal cycles. The main sign that bleeding is needed: the lever returning close to the handlebars before biting, or a spongy feel without the usual progressive response. Annual preventive bleeding is recommended for cyclists covering 5,000 km/year or more.

Yes, high-quality organic pads are versatile; for very wet conditions, hybrid or lightly sintered pads offer better performance. Entry-level organic pads may lose some of their bite when saturated with water. High-end organic pads (Shimano L04C in titanium, SwissStop Disc Race) maintain better wet performance thanks to optimised compounds. For competitive cyclists who frequently ride in the rain, semi-metallic pads offer a good balance between performance and longevity without the drawbacks of pure sintered pads.