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Gearbox Ratios

Commando gear ratios using various boxes and sprockets and speeds per 1000 r.p.m.
 

 

The same AMC gearbox was used on all Commandos, the only change being that from 1974 onwards there was a small difference in the 2nd. gear ratio (not shown in m.p.h. tables). The overall gearing is also affected by the size of the final drive sprocket; usually 19, 20 or 21 teeth, occasionally 22.

Close ratio versions of the gearbox are available.

The tables below show the ratios in each gear, the m.p.h. per 1000 r.p.m., speed at 6000 r.p.m., and the numbers of teeth per gear for standard and close ratio types

 

Standard RGM Close Ratio
(with Kickstart)
RGM Close Ratio
(no Kickstart)
Quaife Close Ratio
  (Road)
Quaife Close Ratio
   (Racing)

 

STANDARD - Ratios
SPROCKETS Engine
26 teeth
Clutch
57 teeth
Rear wheel
42 teeth
Rear wheel size
19" x 4.10
81" circ.
FINAL  DRIVE 19 TEETH 20 TEETH 21 TEETH 22 TEETH
GEAR mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
1st.   6.19 37   6.52   39   6.85   41   7.17   43
2nd.   9.29 56   9.78   59 10.27   62 10.76   65
3rd. 13.01 78 13.69   82 14.38   86 15.06   90
4th. 15.83 95 16.66 100 17.49 105 18.33 110

 

STANDARD - Teeth
GEAR 1st. 2nd. 3rd. 4th.
Mainshaft 14 18 21 23
Layshaft 28 24 20 18
Ratio 2.556 : 1 1.704 : 1 1.217 : 1 1.000 : 1
Mainshaft 2nd. gear was 19 teeth from 1974 onwards; ratio 1.614 : 1

 

RGM CLOSE RATIO (Kickstart) - Ratios
SPROCKETS Engine
26 teeth
Clutch
57 teeth
Rear wheel
42 teeth
Rear wheel size
19" x 4.10
81" circ.
FINAL DRIVE  19 TEETH 20 TEETH 21 TEETH 22 TEETH
GEAR mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
1st.   7.72 46   8.13   49   8.53   51   8.94   54
2nd. 11.31 68 11.90   71 12.50   75 13.09   79
3rd. 13.76 83 14.49   87 15.21   91 15.94   96
4th. 15.83 95 16.66 100 17.49 105 18.33 110

 

RGM CLOSE RATIO (Kickstart) - Teeth
GEAR 1st. 2nd. 3rd. 4th.
Mainshaft        
Layshaft        
Ratio 2.05 : 1 1.40 : 1 1.15 : 1 1.00 : 1

 

RGM CLOSE RATIO (no Kickstart) - Ratios
SPROCKETS Engine
26 teeth
Clutch
57 teeth
Rear wheel
42 teeth
Rear wheel size
19" x 4.10
81" circ.
FINAL DRIVE 19 TEETH 20 TEETH 21 TEETH 22 TEETH
GEAR mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
1st.   8.79 53   9.26   56   9.72   58 10.18   61
2nd. 11.31 68 11.90   71 12.50   75 13.09   79
3rd. 13.76 83 14.49   87 15.21   91 15.94   96
4th. 15.83 95 16.66 100 17.49 105 18.33 110

 

RGM CLOSE RATIO (no Kickstart) - Teeth
GEAR 1st. 2nd. 3rd. 4th.
Mainshaft        
Layshaft        
Ratio 1.80 : 1 1.40 : 1 1.15 : 1 1.00 : 1

 

QUAIFE CLOSE RATIO (Road) - Ratios
 SPROCKETS Engine
26 teeth
Clutch
57 teeth
Rear wheel
42 teeth
Rear wheel size
19" x 4.10
81" circ.
 FINAL DRIVE 19 TEETH 20 TEETH 21 TEETH 22 TEETH
GEAR mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
1st.   6.71 40   7.07   42   7.42   45   7.78   47
2nd.   9.57 57 10.08   60 10.58   63 11.08   66
3rd. 11.72 70 12.33   74 12.95   78 13.57   81
4th. 14.31 86 15.07   90 15.82   95 16.57   99
5th. 15.83 95 16.66 100 17.49 105 18.33 110

 

QUAIFE CLOSE RATIO (Road) - Teeth
GEAR 1st. 2nd. 3rd. 4th. 5th.
Mainshaft 14 17 19 21 22
Layshaft 27 23 21 19 18
Ratio 2.357 : 1 1.654 : 1 1.351 : 1 1.106 : 1 1.000 : 1

 

QUAIFE CLOSE RATIO (Racing) - Ratios
 SPROCKETS Engine
26 teeth
Clutch
57 teeth
Rear wheel
42 teeth
Rear wheel size
19" x 4.10
81" circ.
 FINAL DRIVE 19 TEETH 20 TEETH 21 TEETH 22 TEETH
GEAR mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
mph per
1000 rpm
mph @
6000 rpm
1st.   7.97 48   8.39   50   8.81   53   9.23   55
2nd.   9.57 57 10.08   60 10.58   63 11.08   66
3rd. 11.72 70 12.33   74 12.95   78 13.57   81
4th. 14.31 86 15.07   90 15.82   95 16.57   99
5th. 15.83 95 16.66 100 17.49 105 18.33 110

 

QUAIFE CLOSE RATIO (Racing) - Teeth
GEAR 1st. 2nd. 3rd. 4th. 5th.
Mainshaft 16 17 19 21 22
Layshaft 26 23 21 19 18
Ratio 1.986 : 1 1.654 : 1 1.351 : 1 1.106 : 1 1.000 : 1

 


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