Tire Chart Conversion

 

Aspect Ratio
The aspect ratio of a tire is the relationship of the tire cross section height ( 'H' below) to the cross section width ('S' below). In a tire with an aspect ratio of 85, for example, height is about 85% of the tire width. 'Low profile' tires have as aspect ratio of less than 80. The aspect ratio of a tire is often contained in the size marking, e.g. 130/90 x 16. etc..

Aspect Ratio = ( H / S) x 100

Street Tire Size Designation
Metric

Inch Designation

Alphabetical Designation
Speed Rating (Sustained Speed)
R = 106mph
S = 112mph
T = 118mph
H = 130mph
V = 150mph
Z = 150+ mph
Aspect Ratio
Tire Size Markings

Motorcycle tires are manufactured in a number of different countries with differing requirements in terms of load, dimensions and speed ratings. This has resulted in various size markings. The following chart gives a guide to the relationship between various size markings. THIS CHART DOES NOT IMPLY EXACT COMPARISONS.

 

Motorcycle Street Tire Size Conversion Chart

Front Tires

Rear Tires
Metric Alpha Inch Metric Alpha Inch
80/90 MH 2.50/2.75 110/90 MP85 4.50/4.75
90/90 MJ90 2.75/3.00 120/90 MR90 4.50/4.75
100/90 MM90 3.25/3.50 130/80   5.00/5.10
110/90 MN90 3.75/4.00 130/90 MT90 5.00/5.10
120/80   4.25/4.50 140/80   5.50/6.00
120/90 MR90 4.25/4.50 140/90 MU90 5.50/6.00
130/90 MT90 5.00/5.10 150/80 MV85 6.00/6.25
  150/90 MV85 6.00/6.25

 

Motorcycle Knobby Tire Size Conversion Chart

Front Tires

Rear Tires
Metric Metric Inch Metric Metric Inch
60/100 90/80 2.50/2.75 80/100 80/90 2.50/3.60
70/100 90/90 2.75/3.00 90/100 110/90 3.60/4.10
80/100 100/80 3.00/3.25 100/100 120/80 4.00/4.10
  110/100 130/80 4.00/4.50
120/100 140/80 5.00/5.10