A tire for dry or damp asphalt.
The percentage of grooves on the RX tire complies with the minimum allowed by the FIA technical regulations to ensure maximum duration and efficiency even in the most extreme conditions. The square profile and rigid structure of this tire facilitates steering precision and prompt response.This construction is effective for both slow routes and fast routes with prolonged stress on the tire and fast changes of direction.
It is available in two compounds for specific weather and asphalt conditions. The softer compound is better suited for competition driving on smooth or damp surfaces, and at lower temperatures where a substantial level of grip is required. In these instances, the tread rubber would not be excessively stressed.The harder compound is reserved for special stages that require consistent performance over long distances and at higher temperatures.
The markings that appears on the side of the tires 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 tires.
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:Tire’s technical series. This expresses the ratio 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
Treads of differing versions of rally tires 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
Ensure that tires are fitted by experts, with specialized machinery and equipment under specific safety precautions. Before mounting the tires, clean the surface of the beads and the area of the rim that will come into contact with the tire.
Use ONLY specialized tire lubricants for mounting tires. Do NOT use silicone or petroleum lubricants.
Check the state of the valves to prevent air loss. Check for tightness of metal seals and tearing or cracking in rubber seals. If necessary, replace them. When the tire is being used, always use the valve cover top.
Follow the indications provided on the sidewall of the tire. If specified, refer to the rolling direction and the correct positioning of the internal and external sidewalls.
Use the safety cage when inflating tires. Before removing the tire from the rim during disassembly, ensure that the tire has been fully deflated and remove the inner valve mechanism.
Temperatures measured on the tread are excellent indicatorsof the optimum final compound, and for making ideal corner adjustments on the vehicle, such as camber and toe.
We recommend measuring the temperature at three different points: inner (innermost to the vehicle), center, and outer tread.
In particular, average temperatures must be denoted the table.The difference between the values measured internally, centrally and externally should be less than 20°, while the difference between the front and rear axles should be no more than 25°.
If these values are exceeded, a different final compound should be selected or the vehicle’s geometry should be adjusted.
Working pressure values depend on the size of the tire in relation to the load that it is susceptible to. In other words, working pressure will vary according to the type of car, the weight and the condition of use.
As the weight of the vehicle, speed of travel and force of accelerationincrease, the working pressure of the tire must also be increased. In any case, tires should not be used at pressures below 1.6 bar.
Using extremely low pressures may break the tire 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 tires are preheated or used “cold”. In this instance, preheated tires may be inflated to slightly lower values than cold tires.
The difference will depend on the type of heater, the time it remains and environmental conditions.
The tread on some types of tires may be hand cut to increase the size of the existing grooves.
Hand-cutting is useful for improving grip in certain intermediate situations, between dry and thoroughly wet surfaces, or on mixed gravel/rock and sandy surfaces. The tread efficiency in the conditions for which it was originally designed will no longer be the same.
Hand-cutting must be carried out by experts using specialized equipment, while observing safety regulations.
The color is used to highlight where grooves may be hand-cut.
|TIRE SIZE||VERSION||DIAMETER |
|SECTION WIDTH |
|TREAD WDT |
|ROLLING CIRCUMFERENCE |
|160/560-14 TL||RX5 - RX7||562||175||155||1731||5,5|
|190/580-15 TL||RX5 - RX7 - RX9||578||203||190||1781||6,5|
|200/600-16 TL||RX5 - RX7 - RX9||601||203||195||1854||7|
|200/625-17 TL||RX5 - RX7 - RX9||625||203||205||1929||7|
|225/625-17 TL||RX5 - RX7||625||220||205||1929||8|
|225/650-18 TL||RX5 - RX7 - RX9||646||227||215||1995||8|
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