Which Tyre Size would Fit my Rims?

Planning on getting a set of new rims or second hand rims? Wondering about what tyre specs would fit? Read on.

Before we begin, you need to be familiar with the tyre specifications. The specifications of a tyre can be found on its sidewall and typically look like this:

What it means?

A is the Section Width. In the example above, it means the tyre has a width of 195mm.

B is the Aspect Ration. It is the height of the sidewall expressed as a percentage of the width. In the example, the sidewall is 65% of the width (195), which makes it 195 x 0.65 = 126.75 mm

C is the Tyre construction. R denotes radial construction, which is typical of passenger tyres.

D is the Rim diameter in Inches. So 15 means that the tyre can fit rims of 15 inches.

E is the Tyre Load Index. It represents the maximum weight the tyre can carry. By looking up a Load Index table, 91 (in the example) gives you a load capacity of 615kg.

F is the Speed Index. It is also known as the speed rating as it tells you the maximum speed the tyre is suitable for a full load. By looking up the Speed Index table, you will see that T allows you a maximum speed of 190km/h.

How old are your tyres?

Tyres more than 4 years from the date of manufacturing lose their properties and can be a hazard. Fortunately, the date of manufacturing is stamped on the tyre sidewalls for easy reference. You will see something like this on the sidewall of the tyre:

Look at the last four digits of the code. The first two indicate the week of manufacture while the last two digits represent the year. In this example, the numbers are “3011”. This tyre was manufactured during the 30^th week of the year 2011.

Getting the right tyre size for your rims.

The width of your rims and tyres are closely dependent.

When you change your car rims, make sure the tyre width fits the rim. For example, if your new rims are 15 x 6.0”, there is a range of tyre width that would match. Never go with a tyre with a width that is too wide or too narrow. In this example of a 6″ rim, the tyre width ranging from 175mm to 205mm would fit, with 185mm or 195mm as optimum.

To know which tyre sizing would fit for your rims, refer to the Tyre/Rim width table below.

Once you have the tyre width, the next step is to figure out the Aspect Ratio of your tyres so that you minimize the speed offset due to the change in overall diameter of your wheel. This is a good tool you could use. http://www.willtheyfit.com/