Road vs Track Brake Pads: How to Read a Friction–Temperature Curve

One number isn't enough

Most manufacturers print a single friction coefficient and stop there. "μ 0.5". The problem is that μ isn't a constant. It changes with temperature, speed and line pressure. A pad that's great on the road can run out of brakes by lap three. A race pad can stop poorly on a cold morning.

What AK Master is

AK Master is a standard dyno procedure for brake pads. Pad and disc go on a dynamometer that simulates the car's mass and run through a series of stops: bedding, different speeds, different pressures, a cold start, a ramp up to 500 °C and two fade runs to 550 °C. The output is dozens of graphs. For choosing a pad, one matters most: μ against disc temperature.

Two kinds of curve

A curve that falls with temperature. High μ when cold, then a drop above a certain temperature. That's FF-P1: around 0.54 at 100 °C, steady to 200 °C, then falling towards 0.35 above 300 °C. On the road the discs rarely pass 300 °C, so you get strong, predictable braking from the first stop.

A curve that rises with temperature. Lower μ when cold, climbing with heat. That's FF-P2: 0.43 at 100 °C and 0.54 at 500 °C. In the second fade run to 550 °C it averaged μ 0.63 and never dropped below 0.51. On track, where discs regularly pass 500 °C, the pedal stays the same for the whole session.

Speed

The second graph worth reading is μ across speeds. If friction falls hard from 40 to 200 km/h, the pad bites less exactly where you need it, at the end of the straight. FF-P1 stays between 0.60 and 0.50 across the whole range.

Which one

• Mostly road, a few track days a year: FF-P1.
• Full sessions, racing, or a heavy high-power car: FF-P2.
• Don't put a race pad on a daily driver. It bites less when cold and you'll miss it on the first stop of the morning.

Bedding

Both pads need bedding in. Without it the transfer layer on the disc is uneven and you get vibration and inconsistent friction. The procedure is in the FAQ.