Nankang Sportnex CR-S 245/35 ZR19 (93Y) XL

The Nankang Sportnex CR-S is an Extreme Performance summer tire with a 200-treadwear specifically designed for Club Racers participating in Autocross, Time Attack, HPDE & Circuit Racing. The Nankang CR-S is also listed in the MSUK blue book and is a listed as a 1B tire.

The CR-S's asymmetric tread design is engineered specifically to increase rigidity to provide extreme levels of grip while providing direct steering response. Additionally, the aramid reinforced sidewall provides precise and responsive handling while providing consistent performance.

The CR-S is designed to be a faster tire than the AR-1, but also to be a more consistent tire as well. Furthermore, it is designed to be more road-use friendly with better driving comfort, lower noise & better in wet conditions than the AR-1.

Scrubbing-In

For most purposes, racing tires will benefit from an appropriate ‘scrubbing-in’ procedure. This provides the best combination of performance and longevity under race conditions.

There are several difficulties that arise when using racing tires if they are not scrubbed in prior to use. The most common is 'Cold Graining', where the layer of the tread compound in contact with the track, fails in shear with the layer below. The result is a very visible low frequency, high amplitude rippling effect. This is more common with new tires particularly when used in wet, damp or greasy conditions.

Nankang Motorsport recommends a standard scrubbing in procedure to be used whenever possible (conditions and regulations allowing). This consists of subjecting the tires through:

• Setting the cold air pressure at an adequate psi to handle the weight of the car;
• On track, gradually increase speed subsequently for a minimum three to four laps;
  • With the first lap at 50%-60% of normal usage;
  • Gradually increasing but not to exceed 85% capacity;
• A cool down lap before coming into pit-lane.

Correctly scrubbed in set of tyres will always give more consistent performance over its (much-improved) lifetime than a set that has been used hard from new; even if it hasn’t grained.

Operation Temperature

Measuring tire tread temperatures can be a useful tool for optimising the handling balance of a vehicle. We recommend measuring the temperature at three points across the width of the tre contact patch (inside, middle and outer).

• Temperature Operating Range: 70°C – 100°C
• Tread Temperature Delta (Inside to Outside shoulder): Max 20°C

The quoted values for temperature operating range are when using a needle style pyrometer and recording temperature at the base of the tread. The inside shoulder temperature should be hotter than the outside shoulder. Surface temperature readings will be approx. 30°C lower but can be used as a guide.