How does the size of your Car Tyre affect performance?

Our cars run on the tyres and hence tyres are important and indispensible part of the cars. Our safety is dependent on these tyres and knowing which tyres fit in our car is equally important. While the tyre dealers and tyre companies recommend the tyre size, even we as layman can learn what tyre size goes in our car. This blog will explain in detail about the same.


There are multiple places where you can find information regarding the size of your car’s tyres such as:
• Sidewall of the tyres fitted currently to your car
• Within the car handbook
• Inside the glove box
• Inside the driver door panel
• Inside the fuel flap


If you have a high-end car such as Mercedes or BMW, the size of tyres on the front and rear would be different. Therefore, you need to look for tyre size accordingly.


Tyre size is written in a particular nomenclature and the following are guidelines on how to read the same:
• First three digits of give the measurement of the tyre width across the tread from one sidewall to the other in millimetres.
• The next two digits give a measure of the tyre height as a percentage of the tyre width (also called aspect ratio).
• The next indicator is a letter, and it mentions the type of tyre construction.
• The two numbers after the letter will tell you the wheel rim diameter.
• Finally, you have a load and speed index. The load rating mentioned in numerals will tell you the maximum weight carrying capacity of the tyre. The speed rating is mentioned as an alphabet.


For example, if the specification of your tyre is 265/60R18 92H, then:
Tyre width is 265 mm,
Tyre height is 60% of tyre width i.e., 159 mm.
The tyre has a Radial construction (Most tyres have this type of a construction. The other type is Diagonal and is denoted by D.)
The wheel rim diameter is 18 inches.
The load index is 92 (and as per the load index chart, a load index of 92 means that the tyre can bear up to 630 kg of load).
The speed index is H (and as per the speed index chart, a speed index of H means that the tyre can be safely driven to a maximum speed of 210 km/hour provided it is not loaded above its load index).
To ensure that the car weight is distributed equally across all the four tyres, you must have tyres of the same load capacity. To check the load limits, you need to refer to the car owner’s manual.
If your tyre is worn off, you need to replace it with a tyre of same load index. If you are planning to replace all your car tyres, they should have the same or higher load index as compared to the existing tyres.

You must ensure that you have tyres of the correct load index, because if you make the wrong choice of tyres for your car, your car insurance may become invalidated.
The speed index indicates up to what speed you can drive the car safely if the car is loaded till its load index. If you drive at a speed higher than what the speed index of the tyre states, there is a chance of the tyre bursting due to excessive heat generation. Therefore, the speed index of your car should be more than the speed at which you would normally drive.


There are numerous Car Tyre Dealers in India. With the invention of e-commerce, you can also buy Car Tyres Online at our website www.kwikfixauto.in and have an easier and hassle-free experience. We provide right guidance on which tyre should you install in your car and also provide tyre installation at your location/ doorstep. Please feel free to call us on +91 9950 345 345.

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