Explanation Of Codes And Wording On Tyre Side Walls - Ferrari 2012 F12 Berlinetta Owner's Manual

Explanation of codes and wording on tyre side walls

1) Tyre size and characteristics
Example: 245/35 ZR 20 (105Y)
245 = Nominal width (distance in mm from side to side)
35 = Height/width ratio as a percentage
ZR = Radial tyre that can withstand speeds above 240 km/h
(149 mph). Combined with the specific load and speed code (in
brackets), this indicates a tyre that can withstand speeds above
300 km/h (186 mph).
20 = Rim diameter in inches
5
4
3
2
6
7
8
1
105 = Load index: numerical code associated with the maximum
load permissible on the tyre at a given pressure, at the speed
corresponding to the relative index. The maximum load permissible
is indicated in kg and pounds in the wording (3).
Y = Speed index:
This indicates the maximum speed at which the tyre can withstand
the load indicated in the load index.
Speed indexes (ECE-UN 30) are shown in the table below:
Speed Index
M
N
P
Q
R
S
T
U
H
V
W
Y
ZR (... Y)
The speed index Y, shown in brackets and associated with the
abbreviation ZR, indicates a tyre that can withstand speeds above
300 km/h (186 mph).
Maximum speed (km/h)
130
140
150
160
170
180
190
200
210
240
270
300
> 300
General
1
31