"Judging a motor's performance based on RPM is like judging the weather based solely on temperature. If it is 80 degrees outside, you can be fairly certain it is not snowing, but is it sunny or raining?" - Facts Machine instructions

In other words, the RPMs of a motor are only telling you one side of the story. Two identical motors can top out at the same RPM, but which one gets there quicker? If one tops out after 3.5 seconds, and the other one tops out at 2, are they still the same? Certainly not. The difference between these two motors is going to be the TORQUE each motor makes.

Power is the most important number when looking at an electric motor. It usually is measured in watts and it is the result of the multiplication of RPMs and torque. In the case of the motor discussed above, the second motor gets to top speed quicker, therefore it has more torque. Since power = torque x RPMs we can assume the second motor makes more power.

Power is important because it tells you how to gear motors. The more power a motor makes, the faster it is going to be PERIOD. What I mean by faster is the motor will not only accelerate faster, but also have a higher top speed. This will be the case, if the motor is geared correctly. A motor with tons of RPM and little torque, will need a small pinion. A motor with tons of torque will need a huge pinion and a motor that has a solid combination of both with need an intermediate size pinion.

In order to be able to move on to gearing you have to understand how to select a motor for a specific track. Typically on smaller layouts, you will select a motor that makes LESS power, as it will make you car more drivable as well as allow you to gear it better suited to its power characteristics. By this same logic, on larger tracks, you will select a motor that makes more power in order to take advantage of the motor to its fullest potential.

Selecting a motor correctly is important because if a motor that makes large amounts of power is geared with too small of a pinion, the car will become impossible to drive since it will have too much wheel spin. If it has too large of a pinion, it simply will be too fast to maneuver around a tight course.

Once you have selected the motor best suited for your application, the next important step is to understand how to gear them. With the aid of the graphs from the Dyno tests we can learn how to associate gear ratio with POWER band. What is the power band you ask? The power band is the curve of RPMs v. Torque of any given motor. It will tell you where in this range the motor will make the most power.

The easiest way to look at this is to see where the motor makes the most power in the curve. At this point, the motor is yielding its highest combination of torque and RPMs. This means that at this point, the motor will be at the highest speed it can get to quickly. If the correct gearing is chosen, a motor with more power should accelerate quicker and have more top speed than a motor with less power.

By looking at the graph, you can also tell if a motor makes power based on RPMs, torque, or both. If the graph is skewed towards the right, this means the motor makes more power higher in the RPM range. This is typical of high RPM motors such as the Chili and Anima 2. In the case of these motors, you want to use a small pinion on your car in order to keep it operating on the higher end of the power band (the motor spinning at high RPMs).

If the power graph is skewed towards the left, this means the motor makes a lot power out of torque. Motors with high torque, such as the Atomic Stock and Atomic Stock R love big pinions. They have the grunt to move the large size pinions and make top speed based on long gearing (big pinions). A big pinion will keep the motor operating in the low range of the RPM Range, where it makes its most power.

When selecting the motor you are going to use, don't go for what is fastest or makes the most power. Select what is best suited for the specific application you are going to be using it for. Each track has different characteristics that make motor selection very important in order to get quickly around the track.

Even though the above guidelines are not written in stone, they are great aids in understanding how motors operate and what you are looking for when selecting one that best suits you and your track.