How to read your tyre size
It is printed on the outside of every tyre on your car. Read it to us on the phone and we can quote you and load the right tyre before we leave. Tap any part of the code to see what it controls.
The width of the tyre across the tread in millimetres, measured wall to wall when it is fitted and inflated. Fitting a wider tyre than the rim is designed for changes how the car steers and how the tyre wears.
The sidewall height as a percentage of the section width. Here the sidewall is 45% of 225 mm, so about 101 mm tall. A lower number means a shorter, stiffer sidewall: sharper steering, harsher ride, and a rim that is easier to damage in a pothole.
R is radial construction, which is what almost every passenger car uses. You may also see ZR on high speed rated tyres. LT before the numbers means light truck construction, built for load rather than comfort.
The wheel diameter the tyre is built to fit, in inches. This one is not negotiable — a 17 inch tyre will not go on a 16 inch wheel — and it is the number we most need from you on the phone.
A coded maximum load per tyre. 94 is 670 kg. Fitting a lower load index than the manufacturer specified is unsafe and can void insurance, which is why we match or exceed what came off the car.
The maximum sustained speed the tyre is rated for. W is 270 km/h. It matters less for the speed itself than for the heat the tyre can shed, so we do not fit below the placard rating.
Where to look
On the outer sidewall, usually the largest raised text. The same code is on the placard inside the driver's door frame — that one is the size the manufacturer specified, rather than whatever the last owner fitted.
The four digits worth checking
A code like 3219 is the week and year of manufacture — week 32 of 2019. Rubber ages whether you drive on it or not. Past roughly ten years a tyre should be replaced on age alone, even with tread left on it.
If the four tyres do not match
Front and rear sizes legitimately differ on some cars. Read us the size on the wheel that is actually flat, not the one easiest to reach, and tell us which corner of the car it is on.
Cannot get to the sidewall?
Tell us the make, model, year and trim and we will look up the standard fitment. It is one more thing to confirm on arrival, but it does not stop us coming out to you.
Why we will not fit below your load index
It is the number most often dropped when a tyre is fitted cheaply. A load index below the placard figure means the tyre carries more than it was built for, which shows up first as heat and then as a failure, usually on a hot day with the car loaded. We match or exceed the original on every fitting, including when we are asked not to.
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