Tyre Terminology Explained – Part 2
Here’s part 2 of our tyre terminology explained series – making the world of tyres a little bit simpler…
Looking for replacement tyres, or buying tyres online can be a minefield of confusion terminology and technical terms. It can all be a bit overwhelming, and you may feel too embarrassed to ask for an explanation in person at a garage. Fear not! Here are the most common technical terms, explained in a language anyone can understand:
Load Index – The load index is the weight capacity of the tyre. You should try to use tyres that have a similar load rating as the tyres that came with the vehicle, or the index recommended in your vehicle’s handbook. The higher the number, the larger the load it can carry.
Radial and Bias-ply Tyres – The difference between these two types of tyre comes down to the way the cords, or ‘plies’ inside the tyre are laid. Radial tyres are found on most modern cars as they are more fuel efficient and provide good handling and heat-dissipation. You might find bias-ply tyres on antique/older vehicles, or on some RVs, however. You must never mix radial and bias-ply tyres on the same vehicle as this will dangerously affect your handling.
Temporary Use Tyres – Often known as ‘space-saver’ tyres, these are smaller than usual spare tyres meant to fit easily underneath your chassis or boot in case of a flat tyre. They’re also easier to handle than full-size tyres. However, most space-savers aren’t meant to be used at over 55mph and are only supposed to be used to get you from the roadside to a garage so you can fit a proper replacement tyre.
Treadwear, Traction and Temperature Ratings – These are ratings to provide information on the average lifespan of your tyre, and its ability to stop on wet roads and dissipate heat. The treadwear rating – a three digit number – gives you an idea of how long your tyre should last, although this also depends on the type of driving style you have and mileage you cover. Traction ratings range from AA to C, with C being ‘marginal’ quality. Always ensure your tyres are the minimum traction rating recommended for your vehicle. And finally, temperature ratings (from A to C) refer to the tyre’s ability to dissipate heat when under load. A lower rating indicate a lower capacity for heat, and mean the tyre is more likely to suffer heat-induced failure.
If you’re ever in doubt about the ratings and specifications of your tyres, always consult a professional for advice. Buying cheap tyres online can be a great way to save money, but always buy from reputed companies and refer to your vehicle’s handbook to ensure you are purchasing the right type of tyre for your car.