Tire Conversion Information

Aspect Ratio

Front Tires	Rear Tires
Metric	Alpha	Inch	Metric	Alpha	Inch
80/90	MH	2.50/2.75	110/90	MP85	4.00/4.25
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

The aspect ration of a tire is the relationship of the tire cross section height to the cross section width. In a tire with an aspect ratio of 85, for example, height is about 85% of the tire width. "Low profile" tires have an 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.

Speed Ratings (Sustained Speed)
R = 106 mph
S = 112 mph
T = 118 mph
H = 130 mph
V = 150 mph

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 4.00/4.25

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

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