[How To] Calculating Your Gear Ratio
How To	ID #281

Models must be geared properly to take advantage of the engine's RPM and power range to achieve the desired performance. To increase acceleration while sacrificing top speed, use a gearset that gives you a higher numerical ratio (for example 10:1). To increase top speed while reducing acceleration, use a gearset that gives you a lower numerical ratio (for example 5:1).

Traxxas Nitro models are typically geared to provide the best compromise of acceleration and top speed. The examples above are just for illustration. You will need to calculate the gear ratio of your model in order to make your selection.

The formula is shown below:

The Street Sport gear ratio is calculated differently because it is direct drive. To calculate the Street Sport gear ratio simply divide the number of spur gear teeth by the number of pinion gear teeth.

The Nitro 4-Tec gearing is different because the gear ratios must be changed as 1st and 2nd gear sets in order to maintain compatible gear center distances. There are currently only 3 optional gear ratios available for the Nitro 4-Tec.

The stock gear ratio will provide very high (50+mph-Pro.15 and 60+mph TRX 2.5) top speed. Because of the extreme top speed, the stock gear ratio is primarily intended for flat-out running on large, unobstructed, paved areas. Organized, 1/10 scale, nitro touring car racing is usually done on smaller, closed courses. For this type of racing, change to a lower (numerically higher) gear ratio.

The following chart gives the four possible gear ratio sets. The gear ratios are arranged from highest (lower numerical) to lowest (higher numerical). A brief application recommendation follows each gear ratio set.

	ID #281