Plus Sizing Calculator
Bigger rim, shorter sidewall — without accidentally lifting or lowering the car.
What it does
Given the original tire and a target rim diameter, lists real metric sizes whose overall diameter stays inside 3%, with 2% marked as the safer band.
How to use it
Enter the current size and the rim you want (for example 17 → 18). Results sort by how close diameter stays to original.
How to read the result
Plus sizing (plus 1, plus 2) means larger rim, lower aspect ratio, similar overall diameter. The sidewall gets shorter — sharper steering, a harsher ride, more curb damage. Load index still has to meet or beat the door-jamb spec.
What this does not calculate
We search standard widths and aspects only. Brand availability, load index, speed rating and brake caliper clearance are not in this list.
Does not check whether that size exists in a specific model or fits over your brakes.
Questions
- What is plus zero?
- Same rim diameter, different width/aspect that still matches diameter — used to go wider without changing rims.
- Why is a shorter sidewall riskier?
- Less air and rubber between the rim and the pothole. Plus-size wheels also sit closer to the curb lip.
Related tools
- Reverse Tire Size FinderYou want about 33 inches. We list real sizes that actually sit there — not a fake 273/61R20.
- Free Tire Size Comparison CalculatorThe tool people actually need: will this size change height, width and speedometer — and is it inside 3%?
- Rim Width Calculator by Tire SizeMeasuring width is where the tire is spec’d. Acceptable is the full range. Optimal is near measuring.
- Speedometer Error CalculatorTaller tire: you are going faster than the needle. Shorter tire: you are going slower.
Estimate — not a fitment approval.
