Understanding a Tire Speed Rating Chart – why is Speed rating important?

A tire’s speed rating informs us about the optimal speed that the tire can safely handle over time. It’s the fastest speed a tire can handle before it no longer performs as engineered. The higher the rating, the better control you’ll have at higher speeds. The tire speedrating system was developed to control the safe performance of tires at standardized speeds. A tire’s certified speed rating is given a letter from A to Z, ranging from 5km/h (3mph) to above 300 km/h (186 mph).

When you drive beyond the speed rating, it is not safe to use the tire, and it may burst. as an example: Locating a “Q” on a sidewall would indicate the top of 99mph.

Looking for general Tire size charts and explanations? check here.

How to find the Tire Speed Rating?

You can find your tires speed rating in a number of places:

  • the owner’s manual
  • driver’s side doorjamb
  • glove box door
  • gas tank hatch
  • the sidewall of the tire

All ratings except “Unlimited ZR” incorporate the speed symbol and load index as part of every tire’s service description on the tire’s sidewall.

If you’re reading your tire sidewall, the speed rating will be the last item in the character sequence in the tire’s size code. Below is an example of the description on a tire’s sidewall: 2015/60R15 91V. Here, the tire would have a speed rating of V. V-rated tires can be driven at 149 MPH.

Simple Tires Size description on the sidewall

205/60R15 91V
205 = Section Width in Millimeters
60 = Aspect Ration
R = Radial Construction
15 = Rim diameter in Inches
91 = Load Index
V = Speed Symbol

Tire speed overview in km/h and Mph

Symbol SpeedSpeed (km/h)Speed (mph)
A153
A2106
A3159
A42012
A52516
A63019
A84025
B5031
C6037
D6540
E7043
F8050
G9056
J10062
K11068
L12075
M13081
N14087
P15094
Q160100
R170106
S180112
T190118
U200124
H210130
V240149
W270168
Y300186

ZR Tire Indication

For tires with a maximum speed capability higher than 240 km/h (149 mph), a “ZR” might appear in the size designation. Tires with a maximum speed capability higher than 300 km/h (186 mph), require a “ZR” in the size designation.

Picture by Ildar Garifullin on Unsplash

Related Tire Size charts

Tires Size Chart, Topics

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