Why Is the Tire Break-In Procedure Important for Racing Tires?

In most cases, racing tires will benefit from an appropriate break-in procedure. This ensures better performance and durability during the race.

Problems with Unbroken-In Tires

There are several issues that can arise when using racing tires if they are not broken in before use. The most common of these is called "cold graining". This manifests as a wrinkling effect in the rubber, resembling many very small cracks on the surface. It happens when rubber strips start to separate and tear away from each other, then rejoin under the heat of the tire. This causes a very uneven surface and damages the integrity of the compound, reducing grip, especially in corners and during braking.

Cold graining is caused by overheating due to friction with the road surface. This is the heat that starts at the contact point and penetrates into the compound.

Recommended Tire Break-In Procedure

Nankang Motorsport recommends using a standard break-in procedure whenever possible. This involves subjecting the tires to one gentle heat cycle, followed by gradually increasing the load while avoiding wheel slippage.

• Set the cold air pressure to a level appropriate for the weight of the car.
• On the track, gradually increase speed over at least three to four laps.
• On the first lap, keep the pace at 50%-60% of normal use, gradually increasing but not exceeding 85% of performance, with a cool-down lap at the end of the session.

This will significantly improve tire longevity and performance on the track during future sessions.

Race Preparation

If possible, break in at least one new set of tires during practice and set them aside as a second set for the race. This way, you will know that they have been properly balanced and have no micro-punctures, etc.

Doing this is important because the qualifying session could be wet or marked with a red flag, which may force the use of new tires during the race.

Performance Optimization

It should be noted that new tires will always have a slight performance increase, but this will only be possible if the car is balanced on the tires. A properly broken-in set of tires will always provide more consistent performance throughout its lifespan than a set that was heavily used from new, even if it wasn't grained.

Operating Temperature Range

• Operating temperature range: 70°C - 100°C
• Tread temperature difference (from inner to outer edge): Maximum 20°C

Tread Temperature Measurement

Measuring tire tread temperature can be a useful tool in optimizing vehicle handling balance. Nankang recommends measuring the temperature at three points across the entire width of the tire's contact surface (inside, center, and outside). The provided working temperature range values refer to the use of a needle pyrometer and recording the temperature at the base of the tread.

The temperature of the inner shoulder should be higher than the outer shoulder. Surface temperature readings will be approximately 30°C lower but can serve as a guideline.