NCY GEAR SET 16*37 HAS A 25% INCREASE UP GEAR RATIO OVER 

THE STOCK GEAR SET (13*40 TEETH). 

WHICH WILL PROVIDE HIGHER TOP-END SPEED 

WITHOUT LOSING POWER ON ACCELERATION. 

SINCE THE GY6 125/150CC TRANSMISSION STOCK GEAR

 TEETH ARE 13*40 WHICH = GEAR RATIO 3.076:1

 THIS MEANS THE STOCK GEAR 13-TEETH COUNTER SHAFT 

HAS TO TURN 3.076 FULL-TURNS TO DRIVE 1 FULL-TURN 

OF ITS 40-TEETH FINAL DRIVE GEAR THUS TURNS ITS FINAL

 DRIVE AXLE WHICH THE REAR WHEEL SPIN FREELY ON. 

THE FINAL GEAR RATIO IS THE LAST BIT OF GEARING

 BETWEEN THE TRANSMISSION GEAR AND 

\THE FINAL DRIVE AXLE OF THE REAR WHEEL. 

IN GENERAL, A LOWER FINAL GEAR RATIO WILL LEAD TO

 LESS TORQUE AT THE REAR WHEEL BUT HIGHER TOP SPEED.

 MEANWHILE, A HIGHER GEAR RATIO WILL RESULT IN THE OPPOSITE,

 MORE TORQUE AT THE REAR WHEEL BUT LOWER TOP SPEED.

HERE'S HOW TO CALCULATE THE GEAR RATIO

 FOR TAIDA GEAR SET 16*37. 

JUST DIVIDE THE NUMBER OF FINAL DRIVE GEAR TEETH 37 BY THE

 NUMBER OF THE COUNTER SHAFT TEETH 16. IT'S 37 / 16 = 2.312:1 GEAR RATIO. 

THIS MEANS THE 16-TEETH COUNTER SHAFT GEAR TAKES 2.312 FULL-TURNS

 TO DRIVE 1 FULL-TURN THE LARGER 37-TEETH DRIVE GEAR. 

OVERALL IT WILL TAKE LESS COUNTER SHAFT GEAR TURN FOR THE REAR WHEEL

 TO SPIN COMPARED TO THE STOCK GEAR RATIO OF 3.076:1.

TO CALCULATE GEAR RATIO PERCENTAGE CHANGE IN THIS

 EXAMPLE TAKE (STOCK 40 / 13) - (NCY 37 / 16) = 0.764, 

THEN TAKE 0.764 / (STOCK 40 /13) = 0.248 OR 25% INCREASE

 UP GEAR TAIDA GEAR SET 16*37 OVER THE STOCK. 

IF IT POSITIVE PERCENTAGE IT'S CALLED AN UP GEAR, 

IF IT NEGATIVE PERCENTAGE IT'S CALLED A DOWN GEAR. 

NOW YOU KNOW. GET THE MOST OUT OF YOUR BIG BORE KIT, 

WITH INCREASED TOP SPEED AND A MORE USABLE REV RANGE 

PERFORMANCE WITH THE RIGHT TRANSMISSION 

GEAR SET CHANGED BY NCY.