Tooth Value
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
9
1.00
10
1.11
1.00
11
1.22
1.10
1.00
12
1.33
1.20
1.09
1.00
13
1.44
1.30
1.18
1.08
1.00
14
1.56
1.40
1.27
1.17
1.08
1.00
15
1.67
1.50
1.36
1.25
1.15
1.07
1.00
16
1.78
1.60
1.45
1.33
1.23
1.14
1.07
1.00
17
1.89
1.70
1.55
1.42
1.31
1.21
1.13
1.06
1.00
18
2.00
1.80
1.64
1.50
1.38
1.29
1.20
1.13
1.06
1.00
19
2.11
1.90
1.73
1.58
1.46
1.36
1.27
1.19
1.12
1.06
1.00
20
2.22
2.00
1.82
1.67
1.54
1.43
1.33
1.25
1.18
1.11
1.05
1.00
21
2.33
2.10
1.99
1.75
1.62
1.50
1.40
1.31
1.24
1.17
1.11
1.05
1.00
22
2.44
2.20
2.00
1.83
1.69
1.57
1.47
1.38
1.29
1.22
1.16
1.10
1.05
1.00
23
2.56
2.30
2.09
1.92
1.77
1.64
1.53
1.44
1.35
1.28
1.21
1.15
1.10
1.05
1.00
24
2.67
2.40
2.18
2.00
1.85
1.71
1.60
1.50
1.41
1.33
1.26
1.20
1.14
1.09
1.04
1.00
25
2.78
2.50
2.27
2.08
1.92
1.79
1.67
1.56
1.47
1.39
1.32
1.25
1.19
1.14
1.09
1.04
1.00
26
2.89
2.60
2.36
2.17
2.00
1.86
1.73
1.63
1.53
1.44
1.37
1.30
1.24
1.18
1.13
1.08
1.04
1.00
27
3.00
2.70
2.45
2.25
2.08
1.93
1.80
1.69
1.59
1.50
1.42
1.35
1.29
1.23
1.17
1.13
1.08
1.04
28
3.11
2.800
2.55
2.33
2.15
2.00
1.87
1.75
1.65
1.56
1.47
1.40
1.33
1.27
1.22
1.17
1.12
1.08
29
3.22
2.90
2.64
2.42
2.23
2.07
1.93
1.81
1.71
1.61
1.53
1.45
1.38
1.32
1.26
1.21
1.16
1.12
30
3.33
3.00
2.73
2.50
2.31
2.14
2.00
1.88
1.77
1.67
1.58
1.50
1.43
1.36
1.30
1.25
1.20
1.15
31
3.44
3.10
2.82
2.58
2.39
2.21
2.07
1.94
1.82
1.72
1.63
1.55
1.48
1.41
1.35
1.29
1.24
1.19
32
3.56
2.20
2.91
2.67
2.46
2.29
2.13
2.00
1.88
1.78
1.68
1.60
1.52
1.46
1.39
1.33
1.28
1.23
33
3.67
3.30
3.00
2.75
2.54
2.36
2.20
2.06
1.94
1.83
1.74
1.65
1.57
1.50
1.43
1.38
1.32
1.27
34
3.78
3.40
3.09
2.83
2.62
2.43
2.27
2.13
2.00
1.89
1.79
1.70
1.62
1.55
1.48
1.42
1.36
1.31
35
3.89
3.50
3.18
2.92
2.69
2.50
2.33
2.19
2.06
1.94
1.84
1.75
1.67
1.59
1.52
1.46
1.40
1.35
36
4.00
3.60
3.27
3.00
2.77
2.57
2.40
2.25
2.12
2.00
1.89
1.80
1.71
1.64
1.57
1.50
1.44
1.38
37
4.11
3.70
3.36
3.08
2.85
2.64
2.47
2.31
2.18
2.06
1.95
1.85
1.76
1.68
1.61
1.54
1.48
1.42
38
4.22
3.80
3.45
3.17
2.92
2.71
2.53
2.38
2.24
2.11
2.00
1.90
1.81
1.73
1.65
1.58
1.52
1.46
39
4.33
3.90
3.55
3.25
3.00
2.79
2.60
2.44
2.29
2.17
2.05
1.95
1.86
1.77
1.70
1.63
1.56
1.50
40
4.44
4.00
3.64
3.33
3.08
2.86
2.67
2.50
2.35
2.22
2.11
2.00
1.91
1.82
1.74
1.67
1.60
1.54
41
4.56
4.10
3.73
3.42
3.15
2.93
2.73
2.56
2.41
2.28
2.16
2.05
1.95
1.86
1.78
1.71
1.64
1.58
42
4.67
4.200
3.818
3.500
3.231
3.000
2.800
2.625
2.471
2.333
2.211
2.100
2.000
1.909
1.826
1.75
1.68
1.62
43
4.78
4.300
3.909
3.583
3.308
3.071
2.867
2.688
2.529
2.389
2.263
2.150
2.048
1.955
1.870
1.79
1.72
1.65
44
4.89
4.400
4.000
3.667
3.385
3.143
2.933
2.750
2.588
2.444
2.316
2.200
2.095
2.000
1.913
1.83
1.76
1.69
45
5.00
4.500
4.091
3.750
3.462
3.214
3.000
2.813
2.647
2.500
2.368
2.250
2.143
2.045
1.957
1.88
1.80
1.73
46
5.11
4.600
4.182
3.833
3.538
3.286
3.067
2.875
2.706
2.556
2.421
2.300
2.190
2.091
2.000
1.92
1.84
1.77
47
5.22
4.700
4.273
3.917
3.615
3.357
3.133
2.938
2.765
2.611
2.474
2.350
2.238
2.136
2.043
1.96
1.88
1.81
48
5.33
4.800
4.364
4.000
3.692
3.429
3.200
3.000
2.824
2.667
2.526
2.400
2.286
2.182
2.087
2.00
1.92
1.85
49
5.44
4.900
4.455
4.083
3.769
3.500
3.267
3.063
2.882
2.722
2.579
2.450
2.333
2.227
2.130
2.04
1.96
1.88
50
5.56
5.000
4.545
4.167
3.846
3.571
3.333
3.125
2.941
2.778
2.632
2.500
2.381
2.273
2.174
2.08
2.00
1.92
51
5.67
5.100
4.636
4.250
3.923
3.643
3.400
3.188
3.000
2.833
2.684
2.550
2.429
2.318
2.217
2.13
2.04
1.96
52
5.78
5.20
4.73
4.33
4.00
3.71
3.47
3.25
3.06
2.89
2.74
2.60
2.48
2.36
2.26
2.17
2.08
2.00
53
5.89
5.30
4.82
4.42
4.08
3.79
3.53
3.31
3.12
2.94
2.79
2.65
2.52
2.41
2.30
2.21
2.12
2.04
54
6.00
5.40
4.91
4.50
4.15
3.86
3.60
3.38
3.18
3.00
2.84
2.70
2.57
2.46
2.35
2.25
2.16
2.08
55
6.11
5.50
5.00
4.58
4.23
3.93
3.67
3.44
3.24
3.06
2.90
2.75
2.62
2.50
2.39
2.29
2.20
2.12
56
6.22
5.60
5.09
4.67
4.31
4.00
3.73
3.50
3.29
3.11
2.95
2.80
2.67
2.55
2.43
2.33
2.24
2.15
57
6.33
5.70
5.18
4.75
4.39
4.07
3.80
3.56
3.35
3.17
3.00
2.85
2.71
2.59
2.48
2.38
2.28
2.19
58
6.44
5.80
5.27
4.83
4.46
4.14
3.87
3.63
3.41
3.22
3.05
2.90
2.76
2.64
2.52
2.42
2.32
2.23
59
6.56
5.90
5.36
4.92
4.54
4.21
3.93
3.69
3.47
3.28
3.11
2.95
2.81
2.68
2.57
2.46
2.36
2.27
60
6.67
6.00
5.46
5.00
4.62
4.29
4.00
3.75
3.53
3.33
3.16
3.00
2.86
2.73
2.61
2.50
2.40
2.31
68
7.56
6.80
6.18
5.67
5.23
4.86
4.53
4.25
4.00
3.78
3.58
3.40
3.24
3.09
2.96
2.83
2.72
2.62
70
7.78
7.00
6.36
5.83
5.39
5.00
4.67
4.38
4.12
3.89
3.68
3.50
3.33
3.18
3.04
2.92
2.80
2.69
72
8.00
7.20
6.55
6.00
5.54
5.14
4.80
4.50
4.24
4.00
3.79
3.60
3.43
3.27
3.13
3.00
2.88
2.77
76
8.44
7.60
6.91
6.33
5.85
5.43
5.07
4.75
4.47
4.22
4.00
3.80
3.62
3.45
3.30
3.17
3.04
2.92
80
8.89
8.00
7.27
6.67
6.15
5.71
5.33
5.00
4.71
4.44
4.21
4.00
3.81
3.64
3.48
3.33
3.20
3.08
84
9.33
8.40
7.64
7.00
6.46
6.00
5.60
5.25
4.94
4.67
4.42
4.20
4.00
3.82
3.65
3.50
3.36
3.23
95
10.56
9.50
8.64
7.92
7.31
6.79
6.33
5.94
5.59
5.28
5.00
4.75
4.52
4.32
4.13
3.96
3.80
3.65
96
10.67
9.60
8.73
8.00
7.38
6.86
6.40
6.00
5.65
5.33
5.05
4.80
4.57
4.36
4.17
4.00
3.84
3.69
102
11.33
10.20
9.27
8.50
7.85
7.29
6.80
6.38
6.00
5.67
5.37
5.10
4.86
4.64
4.43
4.25
4.08
3.92
112
12.44
11.20
10.18
9.33
8.62
8.00
7.47
7.00
6.59
6.22
5.89
5.60
5.33
5.09
4.87
4.67
4.48
4.31
Note:
Bigger number = Shorter Gearing = Higher RPM's
Smaller number = Taller Gearing = Lower RPM's
Bigger number = Shorter Gearing = Higher RPM's
Smaller number = Taller Gearing = Lower RPM's
A 'Shorter' Gear Ratio is better for more torque, acceleration, wheelies, and racetracks with short straights.
A 'Taller' Gear Ratio is better for open-rode cruising, lower rpm's, better gas mileage, and tracks with long straights.
Resulting engine speed in RPM from changing the rear sprocket:
RPM before change (x)
teeth new sprocket
teeth old sprocket
teeth old sprocket
Resulting engine speed in RPM from changing the front sprocket:
RPM before change (x)
teeth old sprocket
teeth new sprocket
teeth new sprocket
Road speed at a given engine speed after a rear sprocket change:
speed before change (x)
teeth old sprocket
teeth new sprocket
teeth new sprocket
Road speed at a given engine speed after a front sprocket change:
speed before change (x)
teeth new sprocket
teeth old sprocket
teeth old sprocket
Engine speed at 60 MPH
Overall gear ratio (x) rear tire RPM @ 50 MPH
Rear wheel RPM at 60 MPH
Same as rear tire revolution per mile
Overall gear ratio
Primary drive ratio (x) Individual gear ratio (x) final drive ratio (x) any other drive ratios for engines that transmit power through jackshafts
Speed in MPH at any given engine speed in any given gear
60 (x) engine RPM (+) overall gear ratio in given gear (+) rear tire revolutions per mile
Engine speed in RPM at any given road speed in any given gear
Road speed in MPH (x) overall gear ratio in given gear (x) rear tire revolutions per mile (+) 60
To calculate rear tire revolutions per mile, place the motorcycle on flat pavement. Make a mark on the rear tire and position the mark directly under the axel. Make a mark on the pavement that coinsides with the mark on the rear tire (being sure the mark is directly under the axel. Roll the motorcycle forward , using the mark you made on the tire to note each tire revolution. After a certain number of revolutions,( say 10 for simplicity ), stop the motorcycle with the mark you made on the tire directly under the axle. Again, mark this spot on the pavement. Measure the distance between the two marks you made on the pavement in ft. Tire revolution per mile is then given by: Distance (in feet) between pavement marks ÷ 5280 ÷ tire revolutions (10- or whatever number of revolutions you chose to do). The number you get should be close to 800.
© Superior Sprockets 2008
