The functional differences between the various compounds can be summarized by observing the coefficient of friction as a function of the operating temperature: the RC compound organic Racing, where 350 – 450 ° C. Of operating temperature can be considered normal conditions has a very high coefficient of friction in hot conditions, while the road compounds (such as the sintered road SA) are designed to work best at medium / low temperatures, and precisely around 300 ° C. Therefore the latter, if used on the track and therefore overstressed, will be affected by the “fading” effect, that is the degradation of the friction coefficient: in fact, beyond a certain temperature, they will tend to lose efficiency. On the contrary, using racing compounds on the road (and therefore with cold discs).