TYRE SIZE CALCULATOR for Current Tyre Sizes

Scroll down then select dimensions of tyres to determine the overall diameter


Matching overall diameters if changing wheel & tyre sizes is necessary to ensure ride height & gearing don’t change

Old »
Tyre »
Size »
Tread
Width
Profile
Height
Wheel
Diameter
Overall
Tyre Diameter
  mm   %   inches   inches   mm
It is quite easy to select impossible tyre sizes or sizes that are not made!
New »
Tyre »
Size »
  mm   %   inches   inches   mm
We recommend ±2.5% is the MAXIMUM difference in diameters
Difference in Diameter: percentage =  %
actual =  mm

Use the TAB key to move between the fields then the ARROW keys to select the values
(SHIFT+TAB reverses direction of selection) or the MOUSE selects from the Drop Down Boxes)