How often is it that you have pondered over before changing your wheels - be it upsizing or changing those bald and worn-out tyres? Choosing the rubber for your wheels should be based on your requirements - ride comfort, mileage, speed and performance. Upsizing or sticking to stock should be based on these requirements.
Tyre Sizing
Understanding the size of the tyre is important to make the right choice. The size of the tyre is mentioned on the sidewall, as shown in the figure. It will typically have four variables, for example - 195/60/R15 88V. In the above example, 195 is a tyre's nominal ‘section width,' 60 indicates the aspect ratio or profile. Here 60 indicates that the tyre is 60 per cent of the section width. Higher tyre profile will improve ground clearance, but too much increase will reduce the turning radius.
‘R' specifies that the tyre is of radial construction. Tyre constructions are basically of two types - radial and bias. The construction method affects the durability, ride and fuel economy of the tyres. In India Radial Tyres are the most common on cars, while trucks are still largely based on Bias Tyres.Following the alphabet that indicates the construction is the rim size. Here 15 indicates that the tyre is suited for a wheel with a diameter of 15 inches; 88V indicates the speed and load ratings respectively, the alphabet corresponds to the speed.
Tread Pattern
The design patterns on the tyres are generally designed for specific regions and use. It is designed, keeping in mind the climatic conditions, road surface, temperature, etc. It is classified into performance or summer tyres, all-season tyres, wet weather tyres, winter tyres, all-terrain tyres and mud tyres. Summer tyres typically put performance and grip ahead of longevity by using a softer rubber compound. Tread block design is normally biased towards outright grip rather than the ability to pump water out of the way on a wet road.However, wet weather tyres actually use a softer compound than performance tyres. The rubber needs to heat up quickly in cold or wet conditions and needs to have as much mechanical grip as possible. They'll normally also have a lot more sipping to try to disperse water from the contact patch.
All-season tyres are what you'll typically find on every production car that comes out of a factory. They're designed to be a compromise between grip, performance, longevity, and noise and wet-weather safety. For increased tyre life, they are made with a harder rubber compound, which sacrifices outright grip and cornering performance.
Tyre Upsizing
Stock tyre or rim size are not always the best for the car. Performance and grip are sacrificed in some cases to get better ARAI ratings, which indicate the vehicle mileage. Also, switching to alloys is a good option as these are lighter and improve fuel efficiency. The increased wheel size may cause the wheel to hit the inner wheel wall of the vehicle when the wheel is turned to its fullest. In serious circumstances, it will cause uneven wear and tear for the tyre. Hence, the upsize should be chosen
carefully.
When upsizing tyres without changing the rims, its called a ‘Plus 0' upsize, while increasing the diameter the rim by 1” and 2” is called ‘Plus 1' and ‘Plus 2' upsize respectively. In Plus 1 and 2 upsize, new alloys will have to be purchased. With an increase in the rim size, the profile reduces, which will also lower the ride comfort.