Tyre Code Summary

by Jeff Berton
contriubtor to the Vintage Triumph Register web site,
http://www.vtr.org/maintain/.

For tires using the P-metric designation (e.g., P245/50ZR16)

Format:

[Code][Width]/[Aspect][Speed][Construction][Size]

Code:

P Passenger
LT Light truck
T Temporary
LTP Light truck, personal use

Width:

Width at widest point, sidewall to sidewall, in millimeters.

Aspect Ratio:

Tire height in mm, measured tread to bead, divided by width above, multiplied by one hundred.

Speed ratings:

The maximum speed the tire can maintain at its maximum load rating

Q 100 mph
R 106 mph
S 112 mph
T 118 mph
U 124 mph
H 130 mph
V 149 mph
W 168 mph
Z more than 168 mph

Construction:

R Radial ply
B Bias belted
D Diagonal bias

Size:

The diameter of the wheel the tire is designed to be mounted on, in inches.

Other information:

Maximum Air Pressure This is the max pressure the tire is designed to hold (note this is more than the recommended inflation pressure)
Maximum Load Weight the tire can support
Load Index A code that indicates the maximum weight the tire can carry at its speed indicated by its speed rating
Construction Tells the number and type of plies used in the construction of the tread and sidewall
DOT Serial Number Identifies the plant, manufacturer, and date of production
Tread Wear Index A rating of the tire's resistance to wear. 100 is the reference. A 250 rating indicates 2.5 times the wear resistance of the reference tire. This number cannot be accurately translated to mileage.
Traction Index A rating of the tire's ability to stop on wet pavement. There are three grades, A, B, and C, with A being the best. This index does not reflect the tire's traction performance on dry, snowy, or icy pavement.
Temperature Index A rating of the tire's ability to dissipate and resist heat. There are three grades, A, B, and C, with A being the best.



Created on 17 September 97. Last updated on 30 March 2001. Contact email: is_woolley@yahoo.com. Conforms to HTML 3.2

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