Your tyre’s aspect ratio is one of the most important numbers on the sidewall — but few drivers know what it really means. This figure affects everything from how comfortable your drive feels to how sharply your car handles corners. In this guide, we explain what tyre aspect ratio measures, where to find it, and how it helps you choose the perfect tyres for your vehicle.
If you’ve ever properly looked at your car tyres in great detail, you will have noticed a series of numbers and letters printed on the side of the tyre.
These are linked with the tyre size calculation and are used to ensure you select the right tyres according to the vehicle specifications and your needs as a driver.
Aspect ratio is one of the most important calculations which is linked with the overall tyre size and is found as one of the numbers in a series dictated on the side of your tyre.
In this article, we’re sharing exactly what the aspect ratio is, where to find it, and why it matters.
What is Tyre Aspect Ratio?
Tyre aspect ratio is the height of the tyre, as a percentage of its width.
A higher aspect ratio means a taller tyre sidewall (measured as the distance between the outer rim of the wheel, and the rubber tread of the tyre). This supports a more cushioned driving experience, with luxury vehicles often boasting much higher aspect ratios
Finding Your Tyre Aspect Ratio
The best way to understand how to find and interpret your tyre size ratio is to look at an example…
215 \ 55 \ R16 97V
To help you understand what each component of the tyre size calculation means, we’ve taken the above example and dissected it below.
- 215 – Tyre Width. This is width of the tyre, as measured in millimetres.
- 55 – Aspect Ratio / aka Tyre Profile. This is the height of the sidewall as a percentage of the width.
- R – Construction. This tells you that the tyre is made of Radial construction.
- 16 – Tyre Diameter. The inside rim of the tyre in inches.
- 97 – Load Rating. How much load and vehicle weight the tyre is designed to take.
- V – Speed Rating. This is the maximum speed rating for the tyre.
Note how the aspect ratio on this particular calculation is 55 – that is, the height of the sidewall is measured as 55% of the overall width.
Why is Tyre Aspect Ratio Important?
Now that we know what tyre aspect ratio is, why exactly is it important?
This is the calculation that lets us know how tall the tyre sidewall is – and essentially how well cushioned the vehicle is when on the road.
Typically, a low sidewall and therefore a low tyre aspect ratio means the car exhibits great handling and performance when turning. A wider sidewall and a high aspect ratio reading means more cushioning, with the tyre holding the vehicle higher off the road and offering more in the way of cushioning.
That’s why you’ll often find luxury cars have a high aspect ratio for extreme comfort, while smaller runaround cars have a low aspect ratio.
