The first thing any tyre shop asks is your tyre size, and the answer is printed on the side of the tyre you already have. It looks like a code, but it's easy to read once you know what each part means. We'll use a common size as the example: 205/55R16 91V.

Reading it left to right

  • 205 — the width of the tyre in millimetres, measured across from one sidewall to the other.
  • 55 — the aspect ratio. The sidewall's height is 55% of the width, here about 113mm. A lower number means a shorter, stiffer sidewall.
  • R — radial construction, which almost every car tyre now uses.
  • 16 — the rim diameter in inches. The tyre has to match the wheel exactly.
  • 91 — the load index, the maximum weight each tyre is rated to carry. 91 means 615kg.
  • V — the speed rating, the maximum speed the tyre is rated for. V means 240km/h.

The two numbers people overlook

The load index and speed rating are what get missed, especially on cheap or used replacements. Fitting a tyre with a lower load index than your car needs isn't a technicality. On a ute or van that carries weight, it's the difference between a tyre built for the job and one that isn't. As a rule, a replacement should match or exceed what the vehicle manufacturer specifies.

  • Common speed ratings: T = 190km/h, H = 210km/h, V = 240km/h, W = 270km/h.
  • Light-truck tyres for utes and vans are often marked LT, with a reinforced construction for load.
  • The recommended size and pressures for your car are usually on a placard inside the driver's door or the fuel flap.

The other code: when it was made

Elsewhere on the sidewall is a longer code starting "DOT". Its last four digits are the week and year the tyre was made, so 1223 means the 12th week of 2023. It's worth knowing when you're buying used tyres, and when you're checking how old your spare is.

What to tell us when you ring

Your size, what you drive and how you drive it — mostly town, motorway, gravel or towing. That's enough for us to quote the options that suit. Not sure? Bring the car to 151 Totara Street, Mount Maunganui, and we'll read it for you. Call +64 29 777 7122.