Tyre Knowledge a quick lesson about tyre terms
I have been writing my tyre articles now for about five years. In that time I have used many different terms. Therefore, we use these terms as every day part of our tyre language. It has never entered my head, that my readers may not know what these terms actually mean or stand for.
Tyre Knowledge is what every diver should be familiar with. However, i do think that as long as the car owner knows about the basics, such as the correct tyre pressures and checking them at least every two weeks, should be enough. However I will explain what some of the terms are that I use in my articles. This is tyre knowledge in simple terms.
A typical tyre size would be 205/55R16 followed by 91V
- The 205 is the width of the tyre in millimetres. A tyre marked 205 will measure 205mm across the tread from sidewall to sidewall.
- Aspect ratio is the 55 part of the tyre size and is the ratio of a tyre’s section height (H) to its section width (W). Because, this aspect ratio of 55 means that the profile height of the tyre is 55% of its width.
- The R stands for radial
- Then the 16 is the tyre rim size that the tyre will fit. So in this case the tyre marked 16 will fit on a 16-inch wheel rim. This is measured in inches.
- The 91 part of the number following the tyre size, which is the load index is the maximum load-carrying capacity of a tyre under a specific condition.
- The V is the speed capabilities of the tyre, this can be found on a tyre manufacturer’s chart; the V means that this tyre can safely do 149kh.
Other tyre knowledge things you may read about
- Triangle marks “▲” on the sidewall show the tread groove position of the “tread wear indicators”, the “tread wear indicators” represent 1.6mm. This is the
legal limit that your tyres must not drop below; if it is down to this mark then you should change your tyre.
- Wheel balancing, is a procedure that we carry out to ensure that you wheel is not out of balance and your steering wheel does not shake when driving. Out of balance can be caused by a number of things.
- Reinforced tyre is one with a strengthened sidewall and is used on heavier vehicles and vans. The tyre is marked with a “RF” on the sidewall. Car tyres can be marked with an “XL” which means “extra load”.
- Wheel alignment, is when we check and adjust the vehicles steering geometry.
- Tyre rotation is when we change the tyres from corner to corner to even out the wear.
Finally, I hope that I have covered everything, if I come across any that I have missed in the future then I will update this article’