Your tyre is one of the most important aspects of a car. It helps to bear the car's weight and it maintains grip on the road. Hence, it is important you take good care of it as negligence could cause you your life. There are certain markings on the sidewall of a car's tyre which tells you quite a lot. We will be considering a very easy approach to understanding its meaning.
A basic tyre has the following markings on it:
1. Tyre Name
2. Brand Name
3. Tyre type
4. Tyre width
5. Aspect ratio
6. Construction type
7. Wheel diameter
8. Load index and speed rating
9. DOT tyre identification number
10. Maximum inflation pressure
11. Maximum load rating
12. Tread-wear, traction and temperature grades
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P215/65R15 95H M+S
This set of markings answers numbers 3 through to 8.
a. The ‘P’ signifies the tyre type. In this case it shows that the tyres have been manufactured to certain standards which are meant for Passenger vehicles only. If it begins with ‘LT’ then it is meant for light trucks. That means such tyres need higher inflation and different load capacities than a passenger tyre type. In some cases, you may not see any number at the beginning. This indicates a Euro metric and may have different load capabilities.
b. After the P there is the number ‘215’. This is the tyre width measured in millimetres from sidewall to sidewall.
c. After the ‘/’ the number ‘65’ follows. This is the ratio of the height to its width. In this case, this tyre’s height is 65% of its width. This determines the height or thickness of the tyre as measured from edge of rim to the tyre’s edge. Tyres with ratios above 50% are regarded as high profile tyres while ratios below 50% are regarded as low profile tyres which you will find mainly on high performance vehicles.
d. The ‘R’ signifies ‘Radial’ which is a type of tyre construct. Radial tyres have layers running radially across the tyre and are meant for a certain type of equipment or machinery. Other types of tyre construct include Bias, Solid, Airless etc. To see the different construct types click here.
e. After ‘R’ is the number ‘15’ which signifies the diameter of the wheel and not the tyre’s diameter and it is measured in inches. You could know the tire’s diameter and circumference by using a calculator. Click Here
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| Graphic representation of a Tyre's Dimensions |
f. We proceed to the end of the set which shows ‘95H’ with an added marking ‘M+S’. The metric 95 is a code that shows the maximum load the tyre can support when properly inflated. It is measured in both pounds and kilograms. The H after the number indicates the speed rating which is the maximum speed the tyre can carry a load that corresponds to its load index. So for this case, ‘95H’ means the tyre can carry a maximum load of 690kg/1,520lbs with a maximum speed of 130mph/210km/h.
The M+S means the tyre is designed to perform on both Mud and Snow.
To know your tyre’s load index and speed rating, follow this link Tyre code index.
g. The DOT consists of 12 numbers and letters which identify the factory’s location and the week and year the tyre was manufactured.
The other markings from 10 – 13 are self-explanatory.
Do not buy a tyre simply because it looks good on the vehicle. Always consult your owner’s manual for the recommended tyre size and inflation pressure or seek professional advice.
DO YOU KNOW that a tyre does not carry any expiry date?
Tyres have a manufacturing date but not expiry date. The maximum life span of a tyre is 6 years and it needs to be checked periodically for signs of cracks/crazing and bulging. If any of this exists, the tyre may need to be replaced irrespective of the date of manufacture. New tyres equally need to undergo periodic checks.
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