moteur rpm = jante rpm X rear vitesse ratio X
transmission vitesse ratio
255/50-17
255
Total largeur of the pneu at the sidewalls in millimètres.
This is measured from the outside of the sides of the pneus when mounted
and not the tread or rim largeur.
50
Percentage of the section largeur that is the sidewall hauteur.
For this example the 255mm section largeur multiplied by an aspect ratio
of 50 gives a sidewall hauteur of 127.5mm
17
Jante diametre at the pneu mounting surface in
pouces.