A TYRE FOR DRY AND WET ASPHALT

This product, designed for asphalt, has two longitudinal grooves which means that it can be used both in dry and wet conditions. The two longitudinal channels are positioned on the internal part of the tyre to ensure more effective water drainage and avoid aquaplaning. This also allows better cornering, when the car relies more heavily on the external part of the tyre that generates more grip thanks to a greater contact patch.

RK
TECHNICAL ADVICES

TYRE IDENTIFICATION AND MARKING
TRANSAM/StockCar
TREAD TEMPERATURES
PRESSURE
Tyre identification and marking

The markings that appears on the side of the tyres also tells us the basic size of the tyre, the rim diameter and the width of the rim.
We will illustrate how to read two different types of branding that may appear on the side of the rally tyres.
C: Nominal section width expressed in mm - 225
D: Nominal external diameter expressed in mm - 600
d: Nominal rim diameter of the rim, expressed in inches - 16 
C: Nominal section width expressed in mm - 205
h/C: Tyre’s technical series. This expresses the ration between the section height (in mm) and the nominal section width (in mm) - 65
Radial construction - R
d: Nominal rim diameter of the rim, expressed in inches - 15

The treads of the various versions of rally tyres are described by one or two letters followed by a number. The letters identify the type of tread. 
The number after the letter indicates the type of use, for example: RX 7

TA        
Size Type Section
Width
Aspect
Ratio
Rim
Diameter
Rim
Width
320/660-18 HARD 320 660 18 13
350/720-18 HARD 350 720 18 14


 
TA2        
Size Type Section
Width
Aspect
Ratio
Rim
Diameter
Rim
Width
275/695-15 HARD 275 695 15 10


 
StockCar        
Size Type Section
Width
Aspect
Ratio
Rim
Diameter
Rim
Width
305/660-18 HARD 305 660 18 11
Tread temperatures
​Temperatures measured on the tread are an excellent indicator for deciding the best choice of final compound and for optimising corner adjustments of the vehicle, such as camber and toe.
We recommend measuring the temperature at three different points: inner (innermost side of the vehicle), centre, outer tread.
In particular, average temperatures must be the ones shown in the table, the difference between the values measured internally, in the centre and externally must be maximum 20°, while the difference between the front and rear axles must be no more than 25°.
If these values are exceeded, we recommend a different final compound should be used or the vehicle’s geometry should be adjusted.
Pressure
​Working pressure values depend on the size of the tyre in relation to the load that it is subjected to. In other words, it will vary according to the type of car, the weight and conditions of use.
In particular, as the weight of the vehicle, speeds and accelerations that the tyre is subjected to increase, the working pressure must be increased. In any case, tyres should not be used at pressures below 1.6 bar.
Using excessively low pressures would bring about the breaking of the tyre due to excess force on the sidewall or unseating from the rim. “Hot” working pressures are usually in the range of 2.2 – 2.5 bar.
Initial inflation pressures vary in order to obtain these values, depending on whether the tyres are preheated or used “cold”. Indeed, preheated tyres can be inflated to slightly lower values than cold tyres. 
The difference will depend on the type of heater, the time it remains and the environmental conditions.
Pirelli RK motorsport tyre

PIRELLI OFFICIAL MOTORSPORT DEALERS