Continental TractorMaster is a tyre made in total of 25 sizes, ranging from R20 to R20 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. This tyre profile of 65 means the sidewall height of the tyre is 65% of the tyre width (420mm), which results in 273mm sidewall height. In 420/65 R20, there is only one possible speed index for Continental TractorMaster - "", which is good for speeds up to km/h.