Tyre sizes explained
Buying tyres online sounds harder than it is. There is one code on the side of your tyre, and if you match it, the tyre fits. Here is what each part of it means.
What the numbers on your tyre mean
Every tyre has its size printed on the side. Match these and it fits.
Size: 205/55 R16 91V
Width
How wide the tyre is, in millimetres, across the tread.
Profile
The height of the sidewall, as a percentage of the width. A lower number means a shorter, stiffer sidewall.
Radial
How the tyre is built. Almost every car tyre sold today is radial, so this letter is nearly always R.
Wheel size
The diameter of the wheel it fits, in inches. This one has to match your wheels exactly.
Load index
How much weight one tyre can carry. Fit the same number your car came with, or higher.
Speed rating
The top speed the tyre is built for. Same as your car came with, or higher - never lower.
Where do I find it?
On the outer sidewall of your current tyre, moulded into the rubber. Give it a wipe if it is dirty. All four tyres are usually the same size, but it is worth checking the back ones too - some cars run wider tyres at the rear.
Speed ratings
| Letter | Top speed |
|---|---|
| Q | 99 mph (160 km/h) |
| R | 106 mph (170 km/h) |
| S | 112 mph (180 km/h) |
| T | 118 mph (190 km/h) |
| H | 130 mph (210 km/h) |
| V | 149 mph (240 km/h) |
| W | 168 mph (270 km/h) |
| Y | 186 mph (300 km/h) |
Fit the same rating your car came with, or higher. Going lower is not allowed.
Common load indexes
| Index | Weight per tyre |
|---|---|
| 84 | 500 kg |
| 88 | 560 kg |
| 91 | 615 kg |
| 94 | 670 kg |
| 98 | 750 kg |
| 104 | 900 kg |
While we are at it
Do all four tyres have to match?
They do not have to be identical, but the two on the same axle should match each other in size, type and tread pattern. Mixing across an axle changes how the car brakes and steers.
Can I fit a different size to the one on my car now?
Stick to the size in your car's handbook or on the sticker inside the driver's door. A different size changes your speedometer reading and can affect your insurance.
What does XL or Reinforced mean?
It is a tougher-built tyre that can carry more weight at the same size. If your car came with XL tyres, replace them with XL.
What is a run-flat?
A tyre with stiff sidewalls that lets you keep driving a short distance after a puncture. If your car came with run-flats, it probably has no spare wheel, so replace them with run-flats.