Upsizing in 3 Easy Steps
1. Maintain overall diameter (+/-3%).
2. Keep to the same, or choose a higher LI and SS.
3. Check for wheel arch clearance.
By inching up your tires, we would notice a lot of changes. Firstly, the rim diameter will increase, providing your car with a sportier and trendy look. Secondly, the footprint of the tires will increase, improving the road traction. Also, the sidewall height of the tires will decrease, improving the sidewall strength. With these two improvements, you can get better ride handling, drive control, steering response, more effective braking, and high speed stability.
But before you upsize, take note of some important pointers. The replacement tires you choose must keep the overall diameter, and exhibit the same or higher Speed Symbol (SS) / Load Index (LI) of the original tires as far as possible. An allowance of + or -3% of the original is considered acceptable. This is to ensure your speedometer remains accurate, and to prevent the damage that can be inflicted on an oversized tyre when it rubs against the wheel arch as your car turns.