Home Page Norton Parts For Sale Replica Honda Drum Breaks Works Benelli Replica The Bennett Collection
Big End Bearings Restorations Racing Achievfements Links Contact information
Gear Ratio's
I have included these charts so that people can determine the correct gearbox to use for their application.
From my own experience if a RPM drop of more than 2000 is used the back wheel tends to lock up when changing down.
Standard Manx |
||||
Gear |
Main Shaft Number of Teeth |
Lay Shaft Number of Teeth |
Max Speed MPH @ 6,500 |
Gear Change RPM Drop @ 6,500 |
4th |
23 |
19 |
120 |
600
1130
1660 |
3rd |
22 |
20 |
109 |
|
2nd |
20 |
22 |
90 |
|
1st |
17 |
25 |
67 |
|
Red - I sell these Gears (found on previous page)
Manx With Scarborough First Gear |
||||
Gear |
Main Shaft Number of Teeth |
Lay Shaft Number of Teeth |
Max Speed MPH @ 6,500 |
Gear Change RPM Drop @ 6,500 |
4th |
23 |
19 |
120 |
600
1130
1920 |
3rd |
22 |
20 |
109 |
|
2nd |
20 |
22 |
90 |
|
1st |
16 |
25 |
63 |
|
Red - I sell these Gears (found on previous page)
Standard Road Norton Gearbox 1932 - 1956 |
||||
Gear |
Main Shaft Number of Teeth |
Lay Shaft Number of Teeth |
Max Speed MPH @ 6,500 |
Gear Change RPM Drop @ 6,500 |
4th |
24 |
18 |
120 |
1140
2070
2620 |
3rd |
22 |
20 |
99 |
|
2nd |
18 |
24 |
67.5 |
|
1st |
13 |
29 |
40 |
|
Later Norton Commando |
||||
Gear |
Main Shaft Number of Teeth |
Lay Shaft Number of Teeth |
Max Speed MPH @ 6,500 |
Gear Change RPM Drop @ 6,500 |
4th |
23 |
18 |
120 |
1190
1625
2340 |
3rd |
21 |
20 |
98 |
|
2nd |
18 |
23 |
73.5 |
|
1st |
14 |
28 |
47 |
|
Recommended Gearbox (below) This is the gearbox that we tend to use for hill climbs and sprints. The first gear is low enough to spin the wheel when starting off and has reasonably close jumps in the gears. The second, Third and Forth gears are standard Commando and are available new. The first Gears are special which I make, we have also found this gearbox to be good for formula 3 coopers. |
(These first gears cannot be used with a kick starter)
Gear |
Main Shaft Number of Teeth |
Lay Shaft Number of Teeth |
Max Speed MPH @ 6,500 |
Gear Change RPM Drop @ 6,500 |
4th |
23 |
18 |
120 |
1190
1625
1710 |
3rd |
21 |
20 |
98 |
|
2nd |
18 |
23 |
73.5 |
|
1st |
15 |
26 |
54 |
Red - I sell these Gears (found on previous page)