Installation manual

INTRODUCTION
5
1
1.3.1 Extracting Tire Size From Tire Sidewall Markings
The best way to find out your tire size is to actually look at the tire sidewall. As you can see in
the figure below, there is generally a lot of different information on the tire; however, for our
purpose, we just need 3 pieces of information:
1. Tire Width: the “215” designation
states the Width of the tire in
millimeters at the widest point
from sidewall to sidewall when
mounted on the correct wheel.
2. Tire Height: the “65” designation
is the Aspect Ratio. This ratio is
calculated by dividing the section
Height by the Width. Therefore
the tire height is calculated as:
Height = Ratio * Width / 100
3. Tire Diameter: the “15”
designation is the Diameter of the
wheel rim in inches. This is the
exact size that the tire will fit.
Once the whole list of the nominal values of all the tires has been collected, it is very easy to
understand the application needs, and chose the correct STS400™ model. See the following
sample table:
W [mm] R [%] D [Inch] H [mm] Dint [mm] Dext [mm]
Tire 1 120 70 12 84 304.8 472.8
Tire 2 175 65 14 114 355.6 583.1
Tire 3 185 55 14 102 355.6 559.1
Tire 4 205 60 15 123 381.0 627.0
Tire 5 205 65 15 133 381.0 647.5
Tire 6 190 50 17 95 431.8 621.8
Tire 7 100 100 18 100 457.2 657.2
Tire 8 275 45 18 124 457.2 704.7
Tire 9 275 45 20 124 508.0 755.5
Minimum [mm] 100.0 84.0
Maximum [mm] 275.0 133.3 508.0 755.5
DOF Required [mm]
175.0
Note: Dext is the external tire diameter. Even if this data is not used for the best choice of the
STS400™, the above table shows it. It can be calculated as: Dext = Dint + (2 * H).