Tire Sizes

Tire Sizes
There are basically three different systems of tire description: Inch system (You are probably familiar with it as tire size readings like 5.00 - 16 or 4.50/S/18), the Alphanumeric System (for example: MT 90-16) and the Metric System (for example: 130/90 - 16). The last numbers are to describe the rim size. Before that number there is generally a dash or one of the letters S, H or V. This is key to speed range: (S) tires are up to 112 mph, (H) tires are admissible for speeds up to 130 mph, and (V) tires for 150 mph and up. Alphanumeric System and Series 80 are describing low-profile tires, which means the height is small than the width and the proportions to the width is fixed. Only in the Standard Inch-System can we find tires with equal width and height which is then a "square-profile". 
Metric Alphanumeric Inch-System (Series 90) Inch-System (Series 82)

80/90 ---- 2.75 ----

90/90 ---  MH 90 --- 3.00/3.25 ----

100/90 ----MJ 90 --- 3.25/3.60 ---

110/90 --- ML 90 --- 3.50/4.10 ---

120/90 --- MN 90/MP 90/MR 90/4.00/4.25/4.40

130/90 --- MT 90 --- 5.0 5.10

140/90 MU 90 ---- ----

Tire Charts

Size              Rim           Overall Width              Overall Diameter

120/80V16         2.00            4.7                        23.8

130/90H16         3.00             5.00                       25.4

130/90V16         3.00             5.2                        25.0

500S16              3.00             5.2                        26.4

MT90H16           3.00             5.3                        25.3

130/90H16         3.00             5.4                        25.6

140/90H16         3.50             5.8                        25.6

140/80VB16       3.50             5.9                        24.8

140/90H16         3.50             6.0                        25.8

150/80V16         3.50             6.2                        25.4

160/80H16         4.00             6.4                        26.1

160/80H16         4.00             6.8                        26.1

200/60VB16       5.50             7.9                        25.9

120/80V18         2.75             4.8                        25.9

120/90V18         2.75             4.8                        26.4

120/90H16         2.75             4.9                        26.3

130/80V18         3.00             5.2                        26.3

130/70VB18       3.50             5.4                        25.4
 
150/70VB18       4.00             5.9                        26.2

140/70V18         4.00             6.1                        25.7

170/60VB18       4.50             6.9                        26.0

180/55VB18       5.50             7.0                        26.3

230/50 X 15       7.00/8.00     9.5                        25.3

*Note: Measurements are based on the given rim widths. A rough rule of thumb: Each additional 1/2-inch of rim width will be approximately 1/4-inch more in each tire width. 

Motorcycle Street Tire Size Conversion Charts
Front Tires: 
Metric           Alpha Numerical           Inch

80/90                MH90                2.50/2.75
 
90/90                MJ90                2.75/3.00
 
100/90              MM90               3.25/3.50

110/90              MN90                3.75/4.00

120/80                ----                 4.25/4.50

120/90               MR9                4.25/4.50

130/90               MT90               5.00/5.10

Rear Tires: 
Metric              Alpha Numerical         Inch

110/90               MP85                4.50/4.75

120/90               MR90                4.50/4.75

130/80               ----                    5.00/5.10

130/90               MT90                5.00/5.10

140/80               ----                    5.50/6.00
   
140/90               MU90                5.50/6.00

150/80               MV85                6.00/6.25

150/90               MV85                6.00/6.25

160/80               ----                    6.80/7.00

180/55               ----                    7.00/7.25

200/60               ----                    7.90/8.00

230/50               ----                    9.50

Never put a tire in use that has been subjected to on-the-motorcycle dynamometer engine testing. This severe use of the tire may result in tread compound degradation and subsequent failure

Bent wheel rims and bent or cracked cast wheels should be replaced immediately.

Bent rims may cause wheel wobble, bead unseating and, in the case of tubeless tires, gradual air loss. Sudden wheel failure may result from the use of cracked cast wheels. Be aware of these conditions and their consequences.

 Tubes are a crucial part of the tube-type wheel assembly. They should be treated with respect.

When fitting a new tire on a rim requiring a tube, a new tube should be fitted at the same time. Old tubes become stretched and if an old tube is fitted within a new tire, it can crease and fail due to thinning of the tube rubber. Tubes should be repaired only by an expert. Secure tube valve assembly to rim with care. Inspect rim band and consult motorcycle dealer for correct rim band replacement.

Always check the size markings on the tube to assure that the tire size appears on the tube. Do not fit tubes in radial motorcycle tires, nor fit radials on rims requiring tubes, unless the tubes bear matching size and radial (R) markings.