Most of us know that when the tread depth on our tyres is less than the rim of a 20 pence piece (1.6 mm), it’s time for a change. However, when it comes to buying them most of us are often confused with what the complex codes really mean, resulting in us paying what can be overpriced sums of money for what our local garage recommends. In this article, I aim to break this down into easy to understand terms using Rezulteo’s (https://tyres.rezulteo.co.uk/tyre-advice) helpful guides.
Let’s use “205/55 R16 91W” as our example here – ‘205’ refers to the width of the tyre from the midpoint of each sidewall, in millimeters. The ‘55’ then refers to the height of the tyre’s sidewall in percentage, meaning this tyre’s sidewall height is 205 x 55% = 112.75 mm. ‘R16’ then refers to the rim diameter, in this case 16 inches. These dimensions are specific to your car’s wheels and will not change.
The last digits are important for choosing a tyre to suit your lifestyle, with the numbers referring to your vehicle’s load. Codes read between 20 and 120, with ‘91’ being 615 kg per wheel (allowing for a fully laden car weighing no more than 2,460 kg). The letter then refers to the maximum advisable speed for the tyre, 270 km/h (168 mph) for ‘W’. Full load and speed indexes can be viewed here.
Ensuring maximum longevity is crucial in order to avoid replacing tyres too soon, and why budget tyres aren’t always best in the long run. A premium set of tyres can be expected to last 45,000 km (28,000 miles) while a budget set can last less than 30,000 km (18,500 miles).
Fuel efficiency and wear ratings combined with outright price can result in cost of ownership differing significantly when broken down to cost per kilometer or mile, as Rezulteo highlights here, with the cost of ownership differing by £120 over 90,000 km (56,000 miles).
This is where the EU labeling comes in useful, with A-G ratings for rolling resistance (causing varied fuel efficiency and CO2 emissions), wet weather braking abilities and noise level (sometimes pictured with 1-3 soundwaves rather than an alphabetical rating).
As well as further information including summer and winter tyres, run flats and helpful maintenance tips, Rezulteo also compares prices across some of the UK’s largest suppliers, making the website a go-to one-stop place for all things tyres.