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Speedway Gear Rations

Speedway Gear Ratios
by Kim Gregory

Editors Note: This is from 1996 but I thought it should be available for history purposes if nothing else. The ZIP file mentioned is not available as the program will not run on modern computers. I have it if someone really wants to look at it but you should be a programmer.

You can download this zip file (compiled Jan. 27, 1996) 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
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