Speedway Gear Ratios

You can download this zip file (compiled Jan. 27, '96) containing GEAR.exe (for DOS machines only) and it's 'C' source code. It prints every possible gear ratio for a speedway bike. This will help you pick the ratio you need for different tracks and conditions. This is what it prints out :

use: gear 9000 (engine rpm defaults to 8000rpm, put in your own)
use: gear > out (writes gear ratios to file named "out")
use: gear | more (pauses after each screen full)

formulas used are:
ratio = clutch(44) X wheel sprocket /cshaft(22) X engine sprocket
tire feet per revolution = (27" X (22/7)) /12"
speed = ((8000.0 rpm / ratio) X tire feet per rev) / 5280 feet per mile

ratio engine sprocket wheel sprocket = speed MPH at 8000.0 rpm

ratio 3.810 engine= 21 wheel= 40 MPH = 161.080
ratio 3.905 engine= 21 wheel= 41 MPH = 157.151
ratio 4.000 engine= 20 wheel= 40 MPH = 153.409
ratio 4.000 engine= 21 wheel= 42 MPH = 153.409
ratio 4.095 engine= 21 wheel= 43 MPH = 149.841
ratio 4.100 engine= 20 wheel= 41 MPH = 149.667
ratio 4.190 engine= 21 wheel= 44 MPH = 146.436
ratio 4.200 engine= 20 wheel= 42 MPH = 146.104
ratio 4.211 engine= 19 wheel= 40 MPH = 145.739
ratio 4.286 engine= 21 wheel= 45 MPH = 143.182
ratio 4.300 engine= 20 wheel= 43 MPH = 142.706
ratio 4.316 engine= 19 wheel= 41 MPH = 142.184
ratio 4.381 engine= 21 wheel= 46 MPH = 140.069
ratio 4.400 engine= 20 wheel= 44 MPH = 139.463
ratio 4.421 engine= 19 wheel= 42 MPH = 138.799
ratio 4.444 engine= 18 wheel= 40 MPH = 138.068
ratio 4.476 engine= 21 wheel= 47 MPH = 137.089
ratio 4.500 engine= 20 wheel= 45 MPH = 136.364
ratio 4.526 engine= 19 wheel= 43 MPH = 135.571
ratio 4.556 engine= 18 wheel= 41 MPH = 134.701
ratio 4.571 engine= 21 wheel= 48 MPH = 134.233
ratio 4.600 engine= 20 wheel= 46 MPH = 133.399
ratio 4.632 engine= 19 wheel= 44 MPH = 132.490
ratio 4.667 engine= 18 wheel= 42 MPH = 131.494
ratio 4.667 engine= 21 wheel= 49 MPH = 131.494
ratio 4.700 engine= 20 wheel= 47 MPH = 130.561
ratio 4.706 engine= 17 wheel= 40 MPH = 130.398
ratio 4.737 engine= 19 wheel= 45 MPH = 129.545
ratio 4.762 engine= 21 wheel= 50 MPH = 128.864
ratio 4.778 engine= 18 wheel= 43 MPH = 128.436
ratio 4.800 engine= 20 wheel= 48 MPH = 127.841
ratio 4.824 engine= 17 wheel= 41 MPH = 127.217
ratio 4.842 engine= 19 wheel= 46 MPH = 126.729
ratio 4.857 engine= 21 wheel= 51 MPH = 126.337
ratio 4.889 engine= 18 wheel= 44 MPH = 125.517
ratio 4.900 engine= 20 wheel= 49 MPH = 125.232
ratio 4.941 engine= 17 wheel= 42 MPH = 124.188
ratio 4.947 engine= 19 wheel= 47 MPH = 124.033
ratio 4.952 engine= 21 wheel= 52 MPH = 123.907
ratio 5.000 engine= 16 wheel= 40 MPH = 122.727
ratio 5.000 engine= 18 wheel= 45 MPH = 122.727
ratio 5.000 engine= 20 wheel= 50 MPH = 122.727 - 1/2 mile (Gary Hesmer)
ratio 5.048 engine= 21 wheel= 53 MPH = 121.569
ratio 5.053 engine= 19 wheel= 48 MPH = 121.449
ratio 5.059 engine= 17 wheel= 43 MPH = 121.300
ratio 5.100 engine= 20 wheel= 51 MPH = 120.321
ratio 5.111 engine= 18 wheel= 46 MPH = 120.059
ratio 5.125 engine= 16 wheel= 41 MPH = 119.734
ratio 5.143 engine= 21 wheel= 54 MPH = 119.318
ratio 5.158 engine= 19 wheel= 49 MPH = 118.970
ratio 5.176 engine= 17 wheel= 44 MPH = 118.543
ratio 5.200 engine= 20 wheel= 52 MPH = 118.007
ratio 5.222 engine= 18 wheel= 47 MPH = 117.505
ratio 5.238 engine= 21 wheel= 55 MPH = 117.149
ratio 5.250 engine= 16 wheel= 42 MPH = 116.883
ratio 5.263 engine= 19 wheel= 50 MPH = 116.591
ratio 5.294 engine= 17 wheel= 45 MPH = 115.909
ratio 5.300 engine= 20 wheel= 53 MPH = 115.780
ratio 5.333 engine= 18 wheel= 48 MPH = 115.057
ratio 5.333 engine= 21 wheel= 56 MPH = 115.057
ratio 5.368 engine= 19 wheel= 51 MPH = 114.305
ratio 5.375 engine= 16 wheel= 43 MPH = 114.165
ratio 5.400 engine= 20 wheel= 54 MPH = 113.636
ratio 5.412 engine= 17 wheel= 46 MPH = 113.389
ratio 5.429 engine= 21 wheel= 57 MPH = 113.038 -1/2 mile (Guy Fafard)
ratio 5.444 engine= 18 wheel= 49 MPH = 112.709
ratio 5.474 engine= 19 wheel= 52 MPH = 112.107
ratio 5.500 engine= 16 wheel= 44 MPH = 111.570
ratio 5.500 engine= 20 wheel= 55 MPH = 111.570
ratio 5.524 engine= 21 wheel= 58 MPH = 111.089 -1/2 mile (Guy Fafard)
ratio 5.529 engine= 17 wheel= 47 MPH = 110.977
ratio 5.556 engine= 18 wheel= 50 MPH = 110.455
ratio 5.579 engine= 19 wheel= 53 MPH = 109.991
ratio 5.600 engine= 20 wheel= 56 MPH = 109.578
ratio 5.619 engine= 21 wheel= 59 MPH = 109.206
ratio 5.625 engine= 16 wheel= 45 MPH = 109.091
ratio 5.647 engine= 17 wheel= 48 MPH = 108.665
ratio 5.667 engine= 18 wheel= 51 MPH = 108.289
ratio 5.684 engine= 19 wheel= 54 MPH = 107.955
ratio 5.700 engine= 20 wheel= 57 MPH = 107.656
ratio 5.714 engine= 21 wheel= 60 MPH = 107.386
ratio 5.750 engine= 16 wheel= 46 MPH = 106.719
ratio 5.765 engine= 17 wheel= 49 MPH = 106.447
ratio 5.778 engine= 18 wheel= 52 MPH = 106.206
ratio 5.789 engine= 19 wheel= 55 MPH = 105.992
ratio 5.800 engine= 20 wheel= 58 MPH = 105.799
ratio 5.810 engine= 21 wheel= 61 MPH = 105.626
ratio 5.875 engine= 16 wheel= 47 MPH = 104.449
ratio 5.882 engine= 17 wheel= 50 MPH = 104.318
ratio 5.889 engine= 18 wheel= 53 MPH = 104.202
ratio 5.895 engine= 19 wheel= 56 MPH = 104.099
ratio 5.900 engine= 20 wheel= 59 MPH = 104.006
ratio 5.905 engine= 21 wheel= 62 MPH = 103.922
ratio 6.000 engine= 16 wheel= 48 MPH = 102.273
ratio 6.000 engine= 17 wheel= 51 MPH = 102.273
ratio 6.000 engine= 18 wheel= 54 MPH = 102.273 - Welland (Gary Hesmer)
ratio 6.000 engine= 19 wheel= 57 MPH = 102.273
ratio 6.000 engine= 20 wheel= 60 MPH = 102.273
ratio 6.000 engine= 21 wheel= 63 MPH = 102.273
ratio 6.095 engine= 21 wheel= 64 MPH = 100.675
ratio 6.100 engine= 20 wheel= 61 MPH = 100.596
ratio 6.105 engine= 19 wheel= 58 MPH = 100.509
ratio 6.111 engine= 18 wheel= 55 MPH = 100.413 - Welland (Gary Hesmer)
ratio 6.118 engine= 17 wheel= 52 MPH = 100.306
ratio 6.125 engine= 16 wheel= 49 MPH = 100.186
ratio 6.190 engine= 21 wheel= 65 MPH = 99.126
ratio 6.200 engine= 20 wheel= 62 MPH = 98.974
ratio 6.211 engine= 19 wheel= 59 MPH = 98.806
ratio 6.222 engine= 18 wheel= 56 MPH = 98.620
ratio 6.235 engine= 17 wheel= 53 MPH = 98.413
ratio 6.250 engine= 16 wheel= 50 MPH = 98.182
ratio 6.286 engine= 21 wheel= 66 MPH = 97.624
ratio 6.300 engine= 20 wheel= 63 MPH = 97.403
ratio 6.316 engine= 19 wheel= 60 MPH = 97.159
ratio 6.333 engine= 18 wheel= 57 MPH = 96.890
ratio 6.353 engine= 17 wheel= 54 MPH = 96.591
ratio 6.375 engine= 16 wheel= 51 MPH = 96.257
ratio 6.381 engine= 21 wheel= 67 MPH = 96.167
ratio 6.400 engine= 20 wheel= 64 MPH = 95.881
ratio 6.421 engine= 19 wheel= 61 MPH = 95.566
ratio 6.444 engine= 18 wheel= 58 MPH = 95.219
ratio 6.471 engine= 17 wheel= 55 MPH = 94.835
ratio 6.476 engine= 21 wheel= 68 MPH = 94.753
ratio 6.500 engine= 16 wheel= 52 MPH = 94.406
ratio 6.500 engine= 20 wheel= 65 MPH = 94.406
ratio 6.526 engine= 19 wheel= 62 MPH = 94.025
ratio 6.556 engine= 18 wheel= 59 MPH = 93.606
ratio 6.571 engine= 21 wheel= 69 MPH = 93.379
ratio 6.588 engine= 17 wheel= 56 MPH = 93.141
ratio 6.600 engine= 20 wheel= 66 MPH = 92.975
ratio 6.625 engine= 16 wheel= 53 MPH = 92.624
ratio 6.632 engine= 19 wheel= 63 MPH = 92.532
ratio 6.667 engine= 18 wheel= 60 MPH = 92.045
ratio 6.667 engine= 21 wheel= 70 MPH = 92.045
ratio 6.700 engine= 20 wheel= 67 MPH = 91.588
ratio 6.706 engine= 17 wheel= 57 MPH = 91.507
ratio 6.737 engine= 19 wheel= 64 MPH = 91.087
ratio 6.750 engine= 16 wheel= 54 MPH = 90.909
ratio 6.762 engine= 21 wheel= 71 MPH = 90.749
ratio 6.778 engine= 18 wheel= 61 MPH = 90.537
ratio 6.800 engine= 20 wheel= 68 MPH = 90.241
ratio 6.824 engine= 17 wheel= 58 MPH = 89.929
ratio 6.842 engine= 19 wheel= 65 MPH = 89.685
ratio 6.857 engine= 21 wheel= 72 MPH = 89.489
ratio 6.875 engine= 16 wheel= 55 MPH = 89.256
ratio 6.889 engine= 18 wheel= 62 MPH = 89.076
ratio 6.900 engine= 20 wheel= 69 MPH = 88.933
ratio 6.941 engine= 17 wheel= 59 MPH = 88.405
ratio 6.947 engine= 19 wheel= 66 MPH = 88.326
ratio 6.952 engine= 21 wheel= 73 MPH = 88.263
ratio 7.000 engine= 16 wheel= 56 MPH = 87.662
ratio 7.000 engine= 18 wheel= 63 MPH = 87.662
ratio 7.000 engine= 20 wheel= 70 MPH = 87.662
ratio 7.048 engine= 21 wheel= 74 MPH = 87.070
ratio 7.053 engine= 19 wheel= 67 MPH = 87.008
ratio 7.059 engine= 17 wheel= 60 MPH = 86.932
ratio 7.100 engine= 20 wheel= 71 MPH = 86.428
ratio 7.111 engine= 18 wheel= 64 MPH = 86.293
ratio 7.125 engine= 16 wheel= 57 MPH = 86.124
ratio 7.143 engine= 21 wheel= 75 MPH = 85.909
ratio 7.158 engine= 19 wheel= 68 MPH = 85.729
ratio 7.176 engine= 17 wheel= 61 MPH = 85.507
ratio 7.200 engine= 20 wheel= 72 MPH = 85.227
ratio 7.222 engine= 18 wheel= 65 MPH = 84.965
ratio 7.238 engine= 21 wheel= 76 MPH = 84.779
ratio 7.250 engine= 16 wheel= 58 MPH = 84.639
ratio 7.263 engine= 19 wheel= 69 MPH = 84.486
ratio 7.294 engine= 17 wheel= 62 MPH = 84.128
ratio 7.300 engine= 20 wheel= 73 MPH = 84.060
ratio 7.333 engine= 18 wheel= 66 MPH = 83.678
ratio 7.333 engine= 21 wheel= 77 MPH = 83.678
ratio 7.368 engine= 19 wheel= 70 MPH = 83.279
ratio 7.375 engine= 16 wheel= 59 MPH = 83.205
ratio 7.400 engine= 20 wheel= 74 MPH = 82.924
ratio 7.412 engine= 17 wheel= 63 MPH = 82.792
ratio 7.429 engine= 21 wheel= 78 MPH = 82.605
ratio 7.444 engine= 18 wheel= 67 MPH = 82.429
ratio 7.474 engine= 19 wheel= 71 MPH = 82.106
ratio 7.500 engine= 16 wheel= 60 MPH = 81.818
ratio 7.500 engine= 20 wheel= 75 MPH = 81.818
ratio 7.524 engine= 21 wheel= 79 MPH = 81.559
ratio 7.529 engine= 17 wheel= 64 MPH = 81.499
ratio 7.556 engine= 18 wheel= 68 MPH = 81.217
ratio 7.579 engine= 19 wheel= 72 MPH = 80.966
ratio 7.600 engine= 20 wheel= 76 MPH = 80.742
ratio 7.625 engine= 16 wheel= 61 MPH = 80.477
ratio 7.647 engine= 17 wheel= 65 MPH = 80.245
ratio 7.667 engine= 18 wheel= 69 MPH = 80.040
ratio 7.684 engine= 19 wheel= 73 MPH = 79.857
ratio 7.700 engine= 20 wheel= 77 MPH = 79.693
ratio 7.750 engine= 16 wheel= 62 MPH = 79.179
ratio 7.765 engine= 17 wheel= 66 MPH = 79.029
ratio 7.778 engine= 18 wheel= 70 MPH = 78.896
ratio 7.789 engine= 19 wheel= 74 MPH = 78.778
ratio 7.800 engine= 20 wheel= 78 MPH = 78.671
ratio 7.875 engine= 16 wheel= 63 MPH = 77.922
ratio 7.882 engine= 17 wheel= 67 MPH = 77.849
ratio 7.889 engine= 18 wheel= 71 MPH = 77.785
ratio 7.895 engine= 19 wheel= 75 MPH = 77.727
ratio 7.900 engine= 20 wheel= 79 MPH = 77.675
ratio 8.000 engine= 16 wheel= 64 MPH = 76.705
ratio 8.000 engine= 17 wheel= 68 MPH = 76.705
ratio 8.000 engine= 18 wheel= 72 MPH = 76.705
ratio 8.000 engine= 19 wheel= 76 MPH = 76.705
ratio 8.105 engine= 19 wheel= 77 MPH = 75.708
ratio 8.111 engine= 18 wheel= 73 MPH = 75.654
ratio 8.118 engine= 17 wheel= 69 MPH = 75.593
ratio 8.125 engine= 16 wheel= 65 MPH = 75.524
ratio 8.211 engine= 19 wheel= 78 MPH = 74.738
ratio 8.222 engine= 18 wheel= 74 MPH = 74.631
ratio 8.235 engine= 17 wheel= 70 MPH = 74.513
ratio 8.250 engine= 16 wheel= 66 MPH = 74.380
ratio 8.316 engine= 19 wheel= 79 MPH = 73.792
ratio 8.333 engine= 18 wheel= 75 MPH = 73.636
ratio 8.353 engine= 17 wheel= 71 MPH = 73.464
ratio 8.375 engine= 16 wheel= 67 MPH = 73.270
ratio 8.444 engine= 18 wheel= 76 MPH = 72.667
ratio 8.471 engine= 17 wheel= 72 MPH = 72.443
ratio 8.500 engine= 16 wheel= 68 MPH = 72.193
ratio 8.556 engine= 18 wheel= 77 MPH = 71.724
ratio 8.588 engine= 17 wheel= 73 MPH = 71.451
ratio 8.625 engine= 16 wheel= 69 MPH = 71.146
ratio 8.667 engine= 18 wheel= 78 MPH = 70.804
ratio 8.706 engine= 17 wheel= 74 MPH = 70.485
ratio 8.750 engine= 16 wheel= 70 MPH = 70.130
ratio 8.778 engine= 18 wheel= 79 MPH = 69.908
ratio 8.824 engine= 17 wheel= 75 MPH = 69.545
ratio 8.875 engine= 16 wheel= 71 MPH = 69.142
ratio 8.941 engine= 17 wheel= 76 MPH = 68.630
ratio 9.000 engine= 16 wheel= 72 MPH = 68.182 - Paris (Kim)
ratio 9.059 engine= 17 wheel= 77 MPH = 67.739
ratio 9.125 engine= 16 wheel= 73 MPH = 67.248
ratio 9.176 engine= 17 wheel= 78 MPH = 66.871
ratio 9.250 engine= 16 wheel= 74 MPH = 66.339
ratio 9.294 engine= 17 wheel= 79 MPH = 66.024
ratio 9.375 engine= 16 wheel= 75 MPH = 65.455
ratio 9.500 engine= 16 wheel= 76 MPH = 64.593
ratio 9.625 engine= 16 wheel= 77 MPH = 63.754
ratio 9.750 engine= 16 wheel= 78 MPH = 62.937

Canada + USA Speedway:
http://speedwaybikes.com