motorcycle rims and tires

how do you determine a motorcycles rim size? ?

im pretty sure its on the tire but idk

It is on the tyre. The numbers in front of the dash are the rim width, sometimes in millimetres (that would be a 3-digit number) and if there’s a slash(/) the number after that will be the aspect ratio i.e. height of the tyre in proportion to its width e.g. 40, 50, 70 etc. The number after the dash is the rim diameter in inches e.g 17, 16 or whatever.