Tyre Size Calculator/Tire Plus Sizing Calculator - Calculates Tyre Dimensions for Plus Sizing

Tyre Size Calculator/Tire Plus Sizing Calculator helps you to find the optimal tyre size when you install the larger wheels on a car. It calculates the tyre dimensions for plus sizing.

The tyre plus sizing or the tyre upsizing is the procedure of replacing a wheel with a larger one and mounting a lower profile tyre while keeping an overall tyre diameter and a tyre circumference the same or approximately the same as it is for the original equipment(OE) tyre.

Plus Sizing - Upsizing

The most popular Plus Sizing methods are:

  • Plus Zero - utilizes the same wheel diameter as the OE tyre but combines it with a tyre which has a larger section width and a smaller aspect ratio than the OE tyre.
  • Plus One - utilizes a one-inch larger diameter wheel in comination with the tyre which has a one-step lower aspect ratio than the OE tyre.
  • Plus Two - utilizes a two-inch larger diameter wheel in combination with the tyre which has a two-step lower aspect ratio than the OE tyre.

Beware that the Plus Zero method may require a replacement wheel in order to maintain the proper rim width for a new tyre. Methods: Plus One and Plus Two always require a replacement wheel.

Tyre Plus Sizing Calculator

In order to get the list of optional tyres, which are adequate for your new wheels, in the plus sizing calculator below, select your original equipment(OE) tyre size, the new wheel size and click on "Show Optional Tyres for the New Wheel" - the orange button.

NEW feature: Or, You can display adequate tyres for all three Plus Sizing methods: Plus Zero, One and Two; at the same time, by clicking on the "Show Plus Zero, One 'n Two Tyre Sizes" - the blue button.

The calculator makes a list of optional tyres that have a diameter in the range of -3% to +4% of the difference between the outer tyre diameter and the wheel diameter (D-W).

This formula is used by the leading tyre manufacturers.

Tyre Dimensions

Plus Sizing Calculator

select OE tyre size

eg. 195/65R15

 / R
select new wheel size



Tyre interchangeability is not always possible, so be sure to consult your car manufacturer's manual before changing your tyres. This is for informative purposes only.

When practicing Plus Sizing methods, changing tyres and wheels, please pay special attention to the following: wheel size, width and offset, tyre construction (Radial or Bias-ply), tyre speed rating, tyre load capacity, maximum inflation pressure.

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