rk custom
05-11-2007, 01:41 PM
Tire Conversion Chart
There are three different systems of tire measurement in use:
Inch System (it is well known from tire size readings like 5.00-16 or 4.50/S/18)
Alphanumeric System (the descriptions on tires are like MT 90-16 or MJ90-19)
Metric System (for example 130/90-16).
The last numbers are easy to read. They describe the rim size (which is equal with the inner diameter of the tire).
Before that number there is normally a dash (-) or one of the letters H, S or V. This is the key to the speed range: (H) tires are admissible for speeds up to 130MPH, (S) tires are up to 112MPH, (V) tires for 150MPH and up.
Series 90, Alphanumeric System and Series 80 are describing low-profile tires which means the height is smaller than the width and the proportions to the width is fixed (90% or 80% of the nominal width).
Only in the Standard Inch-System can we find tires with equal width and height, which is then a square-profile.
Metric Alpha Numeric Inch-System
80/90 MH90 2.50 to 2.75
90/90 MJ90 2.75 to 3.00
100/90 MM90 3.25 to 3.50
110/90 MN90 3.75 to 4.00
120/80 4.25 to 4.50
120/90 MR90 4.25 to 4.50
130/80 5.00 to 5.10
130/90 MT90 5.00 to 5.10
140/80 5.50 to 6.00
140/90 MU90 5.50 to 6.00
150/80 MV85 6.00 to 6.25
150/90 MV85 6.00 to 6.25
Motorcycle Street Tire Speed Rating Chart
Symbol Maximum
J---------62 MPH
K---------68 MPH
L---------75 MPH
M---------81 MPH
N---------87 MPH
P---------93 MPH
Q---------99 MPH
R---------106 MPH
S---------112 MPH
T---------118 MPH
U---------124 MPH
H---------130 MPH
V---------149 MPH
Z---------149 MPH
W---------168 MPH
Y---------186 MPH
Tire Load Index
L.I. LB.
33 254
34 260
35 267
36 276
37 282
38 291
39 300
40 309
41 320
42 331
43 342
44 353
45 364
46 375
47 386
48 397
49 408
50 419
51 430
52 441
53 454
54 467
55 481
56 494
57 507
58 520
59 536
60 551
61 567
62 584
63 600
64 617
65 639
66 661
67 677
68 694
69 716
70 739
71 761
72 783
73 805
74 827
75 853
76 882
77 908
78 937
79 963
80 992
(RK, thanks for putting this up! 8)
There are three different systems of tire measurement in use:
Inch System (it is well known from tire size readings like 5.00-16 or 4.50/S/18)
Alphanumeric System (the descriptions on tires are like MT 90-16 or MJ90-19)
Metric System (for example 130/90-16).
The last numbers are easy to read. They describe the rim size (which is equal with the inner diameter of the tire).
Before that number there is normally a dash (-) or one of the letters H, S or V. This is the key to the speed range: (H) tires are admissible for speeds up to 130MPH, (S) tires are up to 112MPH, (V) tires for 150MPH and up.
Series 90, Alphanumeric System and Series 80 are describing low-profile tires which means the height is smaller than the width and the proportions to the width is fixed (90% or 80% of the nominal width).
Only in the Standard Inch-System can we find tires with equal width and height, which is then a square-profile.
Metric Alpha Numeric Inch-System
80/90 MH90 2.50 to 2.75
90/90 MJ90 2.75 to 3.00
100/90 MM90 3.25 to 3.50
110/90 MN90 3.75 to 4.00
120/80 4.25 to 4.50
120/90 MR90 4.25 to 4.50
130/80 5.00 to 5.10
130/90 MT90 5.00 to 5.10
140/80 5.50 to 6.00
140/90 MU90 5.50 to 6.00
150/80 MV85 6.00 to 6.25
150/90 MV85 6.00 to 6.25
Motorcycle Street Tire Speed Rating Chart
Symbol Maximum
J---------62 MPH
K---------68 MPH
L---------75 MPH
M---------81 MPH
N---------87 MPH
P---------93 MPH
Q---------99 MPH
R---------106 MPH
S---------112 MPH
T---------118 MPH
U---------124 MPH
H---------130 MPH
V---------149 MPH
Z---------149 MPH
W---------168 MPH
Y---------186 MPH
Tire Load Index
L.I. LB.
33 254
34 260
35 267
36 276
37 282
38 291
39 300
40 309
41 320
42 331
43 342
44 353
45 364
46 375
47 386
48 397
49 408
50 419
51 430
52 441
53 454
54 467
55 481
56 494
57 507
58 520
59 536
60 551
61 567
62 584
63 600
64 617
65 639
66 661
67 677
68 694
69 716
70 739
71 761
72 783
73 805
74 827
75 853
76 882
77 908
78 937
79 963
80 992
(RK, thanks for putting this up! 8)