Gearing Database

[90GTVert]

This is a compilation of final drive gear ratios shared by members of this forum. If you'd like to add to this listing, please post in the thread linked to below. Include year, make, and model as well as gear ratio info please. If you know the primary and secondary tooth counts, please post them. Thanks.

49ccscoot.proboards.com/index.cgi?action=display&board=2perform&thread=576&page=1


Adly Noble 2T Minarelli
11:1


Aprilia Rally 50 2T Minarelli
12.9:1


CPI Oliver City 2T Minarelli
13.52:1 (Primary 13/52 [4.00], Secondary 13/44 [3.38])


CPI Popcorn 2T Minarelli
13.5:1


2006 Daelim E-Five 2T
14.6:1


2002-2003 Derbi Atlantis 2T Piaggio
12.14:1 (Primary 13/48 [3.69], Secondary 14/46 [3.29])


2009 Genuine Buddy 50 2T Minarelli
11.5:1


Genuine Roughhouse
13:54:1 (Primary : 52/13 [4:1], Secondary : 44/13 [3.38:1])


1984 Honda Aero 125 2T
6.1:1


1984 Honda Spree
84-85 Honda Spree 6.917 ratio 1.8:1 pulley ratio, 12.45 overall reduction
86-87 Honda Spree 6.385 ratio 1.8:1 pulley ratio, 11.49 overall reduction
84-87 Honda Spree Iowa Edition 6.917 ratio 1.8:1 pulley ratio, 12.45 overall reduction
Spree Aftermarket 5.40 ratio 1.8:1 pulley ratio, 9.72 overall reduction


2008 Keeway Venus 50cc 2T Minarelli
11.08:1 (Primary : 13/48 [3.69], Secondary : 12/36 [3.00])


2003 Kymco Super 9 LC 2T
11.5:1


2004 Kymco ZX50 2T
10.5:1


Longjia LJ50QT-H / Vmoto Monza 2 / Grido
13.79:1


Piaggio LT50 (aka Liberty) 49cc 2T
~19.5:1


Polaris Sportsman 90 (ATV) 2T Minarelli
8.83:1 (Primary 15/47 [3.13], Secondary 11/31 [2.82])


2006 Roketa Cayman MC-27-150 GY6 150cc
11.05:1 (Primary 52/16 [3.25], Secondary 51/15 [3.4])


2013 TaoTao ATM50-A1 50cc 4T 139QMB
8.62:1 (Primary 42/15 [2.8], Secondary 40/30 [3.08])


2006 TGB R50X 2T
11.67:1 (Primary 15/50 [3.33], Secondary 10/35 [3.50])


2006 TNG Venice 50cc 2T Minarelli
11.08:1 (Primary : 13/48 [3.69], Secondary : 12/36 [3.00])


2004-2008 Vento Triton 49cc 2T Minarelli
10.13:1 (Primary 16/49 [3.06], Secondary 13/43 [3.31])


2000 Vespa ET2 2T A/C 50cc Piaggio
12.3845:1 (Primary 14/46 [3.857:1] Secondary 13/49 [3.7692:1])

1990 Yamaha Jog CG50
11.75:1

2002 - 2005 Yamaha Zuma 49cc
14.664:1 (Primary 4.0, Secondary 3.666)


2008+ Yamaha Zuma 49cc
13.228:1 (Primary 4.0, Secondary 3.307)

[90GTVert]

From jmkjr72 :

[90GTVert]

Here are some calculations of secondary gear sets for the 139QMB and what the final drive ratio would be with them. For final drive ratio I am assuming stock primary ratio is 3.25:1 (52/16 primary gears). These are common, but I don't think all 139QMBs use these. You will need to know for sure what your gear ratios are to know what your final drive ratio is or will be.

Secondary Tooth Count	Secondary Ratio	Final Drive Ratio w/ 3.25:1 Primary Gears	Brand Or Seller
52/14	3.714:1	12.071:1	Naraku NK900.57
51/15	3.4:1	11.05:1	Common Stock
50/16	3.125:1	10.156:1	Top Racing
49/17	2.882:1	9.3665:1	ScrappyDog, Top Racing, Scooters To Go
42/16	2.625:1	8.531:1	Hoca
46/18	2.556:1	8.307:1	Hoca
41/17	2.412:1	7.839:1	Hoca