XAS with special competition compound”FormuleFrance”
FF stands for Formula France, which is a tyre tread with a mixture that was specifically developed for competition.
It was the first standard tyre designed to run at 210 km/h (131 mph) and its exceptional performance naturally led to the XAS FF being used in Formula France racing from 1968 onwards, circuit racing, rallies and hill climbs.
|Dimension||Seat||Sculpture||TT/TL||Indice de charge||Code vitesse||Largeur boudin (mm)||Diamètre extérieur||Circ. de roulement||Jante de mesure (mini-maxi)||Chambre à air|
|155 HR 13||13"||XAS FF||TT||78||H||157||582||1775||4.0 4.5 5.5||13 D 13|
|165 HR 13||13"||XAS et FF||TT||82||H||175||600||1824||4.0 4.5 5.5||13 D 13|
|185 HR 13||13''||XAS FF||TT||88||H||186||625||1906||4.5 5.5 6.5||13 F 13|
|155 HR 15||15''||XAS et FF||TT||82||H||157||630||1915||4.5 4.5 5.5||15 E 13|
As asymmetrical as a foot!
Michelin made more progress by differentiating the many elements that form the tyre, leading to the creation of the XAS; the first tyre with an asymmetrical tread pattern. The XAS was constructed by taking account of the separate type of work performed by the shoulders, sidewalls and various parts of the crown, depending on whether they are on the inner or outer side of the car. Just like a person’s foot is asymmetrical, the inside and outside of a tyre work differently to provide the vehicle with optimal balance and easy handling.
Like moving on rails!
This major development allowed the XAS tyre to provide:
- outstanding stability,
- exceptional road holding in bends,
- previously unknown levels of grip in all conditions.
The adventure of
The original Formula France was a French single-seater championship, created in 1968, and first level towards reaching Formula 3 racing. The racing cars were fitted with a Renault 8 Gordini 1,300 cm³ / 105 bhp engine and special Michelin XAS FF soft rubber tyres. In 1971, the championship was taken over by Renault, which renamed it "Critérium de Formule Renault", while adopting Formula France sporting and technical regulations before fitting the Renault 16 engine in 1972.
The XAS tyre, launched in 1965, was appreciated for its high driving accuracy and remained the reference tyre until the end of theʹ70s.
It was the first tyre with an asymmetrical tread pattern, with the inside and outside of the XAS working differently to provide good balance to the vehicle.