Marshal MU12 255/40 R21

Marshal MU12 is a summer tyre made in total of 59 sizes, ranging from R13 to R13 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 255/40 R21 is 50mm wider than the narrowest dimension (205) and 20mm narrower than the widest one (275). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (255mm), which results in 102mm sidewall height.