Gear Ratios

Other good pages for  Lambretta gearbox information can be found at: www.scooterstop.co.uk and www.Scooterhelp.com which has an excellent Lambretta gearing calculator

Models Group Teeth Speed Gear Teeth Primary Ratio Overall Ratios
Li 125 Series 1/2 9 1 51 46/15 17:40
Early Li 123 Series 3 12 2 42 10:71
16 3 39 7:47
19 4 35 5:65
Li 150 Special 11 1 50 46/15 13:95
(Pacemaker) 13 2 41 9:67
Late Li 125 Series 3 17 3 39 7:04
19 4 35 5:65
SX150 10 1 50 46/15 15:33
Li 150 Special  12 2 42 10:71
(SX engine) 15 3 39 7:97
150 Grand Prix 19 4 35 5:65
Li 150 Series 1/2/3 11 1 50 46/15 13:95
14 2 41 9:00
17 3 37 6:67
20 4 34 5:22
TV 175 Series 1/2/3 12 1 49 46/15 12:52
SX200 14 2 40 8:76
18 3 37 6:30
21 4 33 4:82
Li 125 Special  10 1 50 46/15 15:33
125 Grand Prix 12 2 42 10:71
15 3 39 7:97
18 4 36 6:32
200 Grand Prix 10 1 50 47/18 13:05
12 2 42 9:13
15 3 39 6:79
18 4 36 5:22
Li 150 Series 2  9 1 51 46/15 17:40
Rallymaster (optional)  12 2 42 10:71
17 3 37 6:67
20 4 34 5:22
GT200 13 1 47 46/15 11:09
15 2 39 7:97
19 3 36 5:81
22 4 32 4:46
Cento 100 10 1 48 45/14 15:43
15 2 43 9:22
21 3 39 5:97
J125 Starstream 11 1 48 45/14 14:02
14 2 44 10:11
16 3 37 7:43
19 4 34 5:75
J125 3-Speed 11 1 48 45/14 14:02
16 2 42 8:44
21 3 37 5:66
Luna 75cc Vega/Cometa 9 1 48 46/13 19:27
13 2 44 12:52
16 3 37 9:29
  20 4 34   6:90
Alternatively click here for a crap copy from the Lambretta tuning manual.