Plus-sizing wheels and tyres without spoiling the ride
Going up a wheel size only works if the tyre gets shorter to match. Here is the simple maths, and what changes on Indian roads.
Written by WheelStop's fitment team, cross-checked against Indian vehicle specs. Last updated .
What is plus-sizing?
Plus-sizing means fitting a larger-diameter wheel with a lower-profile tyre so the overall tyre height stays almost the same. Plus one is one inch larger, plus two is two inches larger. Keeping the overall height close to stock keeps your speedometer accurate.
How do I calculate overall tyre diameter?
Sidewall height equals tyre width times the aspect ratio divided by 100. Overall diameter equals the wheel diameter in millimetres plus two sidewalls. For a 185/65 R15 tyre: sidewall is 185 × 0.65 = 120 mm, wheel is 15 × 25.4 = 381 mm, so overall diameter is about 381 + 240 = 621 mm.
What is a worked plus-one example?
Move that same car to a 16-inch wheel. Wheel diameter becomes 406 mm. To stay near 621 mm overall, each sidewall should be about 107 mm, which with a 195 mm width is roughly a 55 aspect ratio, so a 195/55 R16. Check the final overall diameter is within about 2 to 3 per cent of stock.
What changes on Indian roads?
A lower-profile tyre has less sidewall to absorb potholes, so the ride gets firmer and the wheel is easier to bend or crack on bad surfaces. Larger wheels also cost more to replace. Consider how rough your regular roads are before going up two sizes.
What else must I check besides diameter?
Check the bolt pattern, offset, width and clearance inside the arch at full steering lock. Our size guide covers stock sizes by model, and the fitment checklist covers the rest.