Introduction
The tire is the interface with which the car is connected to
the road. Acceleration, deceleration, downforce and changes in direction are
all transmitted through the tires.
 |
| Slick Tire |
 |
| Grooved Tire |
Since 2009 Formula 1 has gone back to slick tires from grooved
tires. Slick tires provide more grip due to the higher surface area of rubber
in contact with the road, what is referred to as ‘the contact patch’. Slick
tires were also used pre 1998, but from 1998 to 2008 the sport decided to
change to grooved tires because they provide less grip, to try and simulate the
grip levels of a wet track because it produced a better show.
The size of the tires is limited by regulations; the size of
the rear tire must be 325/45R13
while the front tire must be 270/55R13.
Taking for example the rear tire, what these measurements mean is that the
width of the tire must be 325 mm
wide and the diameter of the wheel rim must be 13’’ or 330 mm. The 45R figure gives the aspect ratio of
tire sidewall height to tire width. The tire sidewall is 45% the height of the
tires width, 45% of 325mm is 146.25 mm. So
the overall height of the tire is 2(146.25)
+330 which is equal to 622.5 mm for
dry tires. Wet weather tires are slightly taller to increase the car’s ride
height and prevent the floor or the front wing from hitting any standing water
on the track. If that would happen downforce would be lost at that instant and
the driver would probably lose control.
Coefficient of
Friction
