Downsizing Tyres for Winter Tyres
by Brian, under Cars, Safety & Advice.
Winter tyres are a less popular choice amongst vehicle owner. This despite the fact that more than sixty percent of the accidents in winters happen because of absence of correct tyres that can form a firm grip on the road. The slush and wetness on the roads can make a car using summer or all-season tyres skid through the road and thus, meet with several accidents. Some of these can be potentially fatal.
For others, who do believe in changing tyres for winters, it is common practice for vehicles equipped with all season or summer tyres to switch to a set of tyres apt for winters to bear the cold and snowy seasons. All-season tyres provide vehicles with maximum wear through all weather conditions. Yet these types of tyres are not designed to provide you with maximum grip in cold or icy conditions.
Instructions for Downsizing to Winter Tyres
First Learn to Read Tyre Size’s
The most important part in enhancing the performance of winter tyres is to have the right size of tyre fitted on the wheel of your vehicle. To read the tyre size, locate the O.E. tyre size. This can be found on the sidewall of the tyre and will look like: 255/50R17. Note the width of the tyre from the first number in the tyre size. In this case, number 255 represents the width across the tyre, in millimetres, from the widest point of the tyre.
Then, calculate the tyre sidewall height. In this example of tyre size, 255/50R17, number 50 represents the height of the tyre’s sidewall as a percentage of the tyre width. Thus, in this case the tyre’s height would be around 127.5 millimetres (that is, 50 percent of 255). This is also known as the tyre’s series.
Next locate the O.E. diameter of the wheel; this is the last number in the tyre size. In the example discussed here, 255/50R17, number 17 represents the wheel diameter measured in inches, on which the tyre is intended to be mounted.
Next Step is Calculating Tyre Diameter
Now you can proceed to calculate the overall tyre height, in inches, with the use of the following formula – ((Width/25.4) x Sidewall Percentage) x 2
To illustrate let us take the same example as above. Here a 255/50R17 tyre would have an overall tyre height of 10.04 inches by using the above mentioned formula ((255/25.4) x 50%) x2.
Now combine the overall tyre height with the diameter of the wheel. Using the same example of, 255/50R17, you would add 10.04 to 17, the tyre height, for a final diameter size of 27.04 inches. Now for an appropriate range you can use the 3 percent variance rule. Now you will be able to install a new tyre and wheel combination that is between 26.23 inches and 27.85 inches in diameter in total.
These calculations will ensure that you put your money at the right place without the risk of getting an altogether wrong tyre.