TYRE SIZE CALCULATOR  
Select the dimensions of your tyres to determine the overall diameter
Correct matching of overall diameter when changing wheel and tyre sizes
is necessary to ensure ride height and gearing remain the same
Original »
Tyre »
Size »
Tread Width Profile Height Wheel Diameter Overall Tyre Diameter
  mm   %   inches   inches   mm
NOTE: it is quite possible 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 use the MOUSE to select from the Drop Down Boxes