I’ve thought about upgrading my Wheely King by adding the best brushless motor to my RC truck. After reading a few reviews, I realized I would grenade the transmission — quick!
A brushless RC motor and ESC are commonplace in many radio controlled cars and trucks nowadays — as well as RC planes and drones.
Because I did do some research about buying a brushless motor for an RC car, I thought I would list considerations.
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The vehicle the motor will go in really impacts what motor you purchase.
Example: The gears in my truck would not last with any brushless motor unless the transmission gears were replaced with metal units.
Upgrades to the transmission, bearings, and carriers may be needed, so it’s important to have a budget as a starting point.
Starting point: Manufacturer recommendations
Does the manufacturer recommend any specific motor for your model of RC car?
See if the manufacturer recommends a specific motor. Also, consider checking out RC forums, where others have done similar upgrades.
A quick example is the Traxxas Stampede. It’s fairly easy to upgrade to brushless.
Traxxas already makes the Stampede in a brushed and brushless version. The brushed version has different vehicle parts and electronics.
A quick look at the parts list for both gives an indication about what needs to be upgraded with the electronics.
How much can you afford?
Factor in upgrades and the cost of the motor and speed control.
You can also look into buying combination packs including the motor, brushless ESC and programming cards depending on your needs or wants.
There are so many RC car brushless motor brands, such as Castle Creations, Tacon, Leopard, Traxxas, ARRMA, Axial, Dromida, Duratrax, Graupner, Hot Bodies, HPI Racing, LRP, Muchmore Racing, Novak, RC Gear Shop, Tamiya, Tekin, TrakPower, Trinity, and so many others.
With this many brands, it makes it easy to find a motor that fits your vehicle. And fit is important.
Size matters: So size ’em up!
Although a good Dremel or rotary tool can be the answer to most RC car fit issues, it’s not a good idea in this case.
The most important information when buying a good brushless motor is making sure it fits your vehicle.
Find the diameter and length for the actual motor you are considering.
Measure the space in your vehicle.
Will the motor fit your RC car housing? Does the motor fit the car?
You want to make sure the motor will fit properly into your RC car.
If it doesn’t, find one with the correct physical dimensions to fit.
Spacing, output shaft diameter
Another important dimension is center spacing. You want the motor to mount properly.
The diameter of output shaft is important, too. The pinion (the small gear that attaches to the motor) needs to fit the output shaft.
Let’s get technical
There are several terms you need to look at when buying a brushless motor.
The first term is the “t”. It stands for turns. The lower the turn count, the faster the motor will spin — also known as motor’s revolutions per minute (RPM).
The next term is “KV”. The higher the KV the faster the rotor spins leading to more speed but less torque. The lower KV ratings will have powerful torque but lower top speeds.
Keep in mind this is all theoretical. It assumes the motor is under no load — that is there’s no gearing, no resistance, no vehicle being propelled forward.
Speed and acceleration can be tweaked using gear ratios, so don’t go searching for the best RC motor for speed. Know there are other variables you can adjust, too.
Electronic speed control
The ESC is just as important as the motor. It needs to be based on the wattage and amperage draw of the motor.
Because the ESC supplies power to the motor, servo, and receiver, it needs to be rated at a higher wattage and amperage than for just the motor so it can supply the correct electrical needs to each component.
What is your goal for you RC car? Racing or backyard bashing? How fast do you want the car to go?
These are all good questions to ask yourself before making a purchase. An answer will determine your choices.
Newer RC car drivers may want to look for a lower motor rating. The higher KV ratings may lead to difficultly in driving the RC car. You can always change out the motor as your skill increases.
If you are looking to race your RC car, you may need to look at the different racing classes you wish to race in to see what motor is appropriate. The racing class will usually determine the motor you should use.
Off road vs. on road: If you are looking for on road racing, you may want a higher KV rating for the speed.
If your focus is more on off road you may want to opt for a lower KV so that your car has the required torque and maneuverability for the terrain.
For those of us who used brushed motors for years, there’s a benefit of not worrying about changing brushes, springs, and getting the motor’s commutator cut.
Brushless motors remove a lot of the maintenance headaches. But, they do require maintenance.
They should be blown clean by using compressed or canned air. Then, use lightweight oil on the bearings and you’re good to go.