Originally Posted by
Derby Bros Racing
Are you talking in terms of acceleration?
The internal ratio is affected a lot with your main gearing (pinions and spurs). Changing to smaller pinions will gain accelaration if that is what you are looking for. Changing the pulleys will affect your overdrive. The car in stock form is almost 1:1 with a 0.5mm split between front and rear tires.
If you are looking for more turn in and quicker speed in turns, you may want to raise your rear roll center.
Even with the smallest pinion and biggest spur, it is possible that the car cannot achieve the same acceleration as a car with a higher internal ratio. Changing the brake pulley and differential pulley's tooth count allows us to change the internal ratio which can then increase or decrease acceleration as well as theoretical top speed. By changing the pulleys else where, this affects the overdrive ratio ie. 2sp side pulley, side pulley, middle shaft pulley and 1 way pulley.