The ratio expresses the number of turns required by the pinion (which is attached to the output shaft of the transmission) to turn the drive axle one revolution, i.e. 2.80 means the pinion must turn 2.80 times to turn the drive axle once. A higher number (6.50) means a lower (or shorter) gear. Short gearing gives quicker acceleration, but because the engine must turn faster, fuel mileage and top speed are lower. Tall gears give smoother acceleration and higher top speed, at the expense of quick acceleration.

We are allowed to choose from no less than 38 different ratios with an adjustment range from as low as 2.80 to as high as 6.50. The final ratio you will need is different for every track you compete at and is the most common gear changed on a ARCA/Remax race car. When you change the final ratio, you change all the drive ratios together proportionally.

On short tracks you will want to choose a higher final ratio because quicker acceleration will be a must at tracks where speeds are not as high. At super speedways you'll want a smaller ratio for top speed since quick acceleration is not necessary on a track where you're at full throttle most of the time. The most important factor when considering what ratio to use is that you don't choose a ratio that is too high. Too high a final ratio will result in running higher rpms. If, by the time you reach the end of a straightaway, you're running higher than 9000 rpms. you risk having your rev limiter kick in. This will result in a loss of torque and thus a loss of speed. The rev limiter is used to prevent us from running too high an rpm, which could result in a blown engine. You must watch your tach when changing gear ratios. If you're running too high an rpm you will also notice it through the sound of your engine as a missing sound.

As you adjust other chassis components, you will most likely find yourself having to change your final ratio. As you find more speed through the corners, you'll eventually find yourself on the throttle quicker. Since you're on the throttle sooner you will be running a higher rpm towards the end of a straightaway. This is likely going to force you to make a final ratio change.

Final Ratio synopsis:

• The higher the ratio/number (6.50) the higher the rpms. Provides quicker acceleration, but slower top speeds.

• The lower the ratio/number (2.80) the lower the rpms. Provides slower acceleration, but higher top speeds.

Transmission Ratios
The transmission ratio represents the number of engine revolutions to rear wheel revolutions. The transmission ratios can be viewed for all four gears. These 4 ratios change automatically whenever the final ratio is changed and will change individually per gear whenever a transmission ratio is changed.

Like the final ratios, the transmission ratios are read in the same manner. A higher number means a lower (or shorter) gear. Short gearing gives quicker acceleration, but because the engine must turn faster, fuel mileage and top speed are lower. Tall gears give smoother acceleration and higher top speed, at the expense of quick acceleration.

Your highest transmission ratio will be in 1st gear and should get smaller as you move through the gears.

Transmission Ratios synopsis:

• The higher the ratio/number the higher the rpms. Provides quicker acceleration, but slower top speeds.

• The lower the ratio/number the lower the rpms. Provides slower acceleration, but higher top speeds.