Ride On Motor Guide

From left to right:
Stock Power Wheels 550
RCX2 Titan 21T
ML Toys 550 (I have not had a chance to test these yet)
Stock Bravo Grave Digger
ML Toys 775
Traxxas Titan 775

This is going to be a short write up on different 550 and 775 size brushed motors I have tried and my experience. I have tested enough motors to have an idea of their performance but there are many more than what is listed here and note that I am not an expert in brushed motors.

Motor Sizes

Brushed DC motors come in two sizes that easily fit into the gear boxes of Power Wheels and other ride on kids toys, most stock 12V vehicles will have 550 motors and 24V vehicles will have 775 size. The larger 775 motors are typically lower RPM but have higher power ratings than the 550 motors, that means to achieve the same top speed of a 550 the voltage on the 775 will need to be increased. Note that this is a very general statement and is not always true.

Where does the name 550 or 775 come from?

The name "550" for a 550 motor comes from its approximate can size, specifically its length and diameter. The numbering system is a general convention used in DC motor classification, though it doesn’t always directly correspond to precise measurements.

Why "550"?

• The "5" refers to the motor series or size class, indicating a smaller, more compact motor relative to others like the 775.

• The "50" roughly corresponds to the length of the motor's body (can), which is approximately 50 mm.

This naming convention is widely used in brushed and brushless DC motors to differentiate between different sizes and power classes. For example:

• 370 Motor: Smaller, with a body length of ~37 mm.

• 775 Motor: Larger, with a body length of ~75 mm.

Key Points:

• The "550" designation doesn’t specify exact dimensions, but it serves as a quick identifier for manufacturers and users to gauge the motor's size and application suitability.

• The system isn’t standardized across all brands, so actual dimensions and specifications can vary slightly depending on the manufacturer.

550 Motor Dimensions

1. Can Diameter: ~35.8 mm (1.41 inches)

2. Can Length: ~50 mm (1.97 inches)

3. Shaft Diameter: ~3.17 mm (1/8 inch)

4. Shaft Length: ~12–15 mm (varies by manufacturer)

5. Mounting Hole Distance: ~25 mm (center-to-center, across the mounting flange)

550 Electrical Specifications

• Voltage: Common operating voltages are between 6V and 18V, with some models designed for higher voltages.

• Current: Continuous current ratings typically range from 2A to 8A, with peak currents up to 15A or more under heavy load.

• Power Output:

  • At 12V: 50W to 150W (watts) for most standard motors.

  • Higher-performance or modified 550 motors can achieve power outputs of up to 200W or more when paired with robust controllers and adequate cooling.

775 Motor Dimensions

1. Can Diameter: ~42 mm (1.65 inches)

2. Can Length: ~66.7 mm (2.63 inches)

3. Shaft Diameter: ~5 mm

4. Shaft Length: ~16–20 mm (varies by manufacturer)

5. Mounting Hole Distance: ~29 mm (center-to-center, across the mounting flange)

775 Electrical Specifications

• Voltage: Common operating voltages range from 12V to 24V, with some models designed for higher voltages.

• Current: Continuous current ratings are typically 5A to 15A, with peak currents reaching 30A or more under heavy loads.

• Power Output:

  • At 12V: 100W to 300W (watts) for standard models.

  • At 24V: 200W to 600W for high-performance or specialized 775 motors.

Key Differences to consider when switching from 550 to 775

• Size: The 775 motor is larger in both diameter and length, offering more space for windings and typically higher power output.

• Shaft Diameter: The 775 motor has a thicker shaft, which is better suited for handling higher torque loads.

• Mounting: The mounting hole spacing and flange size are different, so upgrading from a 550 to a 775 motor may require an adapter or modifications to the mounting plate.

Motor Turns

The term "turns" in the context of DC motors, including brushed motors like the 550 and 775 sizes, refers to the number of wire windings (turns) on the motor's armature or rotor. This characteristic significantly affects the motor's performance, part

What "Turns" Represents

• Turns is the number of times the wire is wrapped around each pole of the armature in the motor.

• It is typically represented in specifications as a single number, e.g., "12T" for 12 turns.

How Turns Impact Motor Performance

Lower Turns (e.g. 10T, 12T):

• Higher Speed (RPM): Motors with fewer turns spin faster because they experience less resistance and inductance.

• Lower Torque: These motors produce less torque per amp and are better suited for lightweight or high-speed applications.

• Higher Current Draw: They draw more current, leading to more heat and requiring robust controllers and batteries.

Higher Turns (e.g. 21T, 27T):

• Lower Speed (RPM): Motors with more turns spin slower due to higher resistance and inductance.

• Higher Torque: These motors produce more torque and are ideal for heavy loads or applications requiring more pulling power.

• Lower Current Draw: They are more energy-efficient, making them suitable for applications requiring longer run times.

Personal Experiences

I have tested with the following motor configurations so far:

12V

• Stock Power wheels 550 (I believe these are ~30T motors based on the performance with respect to known turn 550 motors)

  • These will run forever, I would be amazed if someone wore the brushes out on a stock motor at 12V, my son drove a Power Wheels Jeep at 12V for an entire summer and the brushes didn’t even look worn. My wife and I estimated over 100 miles based on the size of our lawn and how many days he was out there driving it around. We may be way off on the distance, but it was far.

• Traxxas Titan 21T (There is a 12T version, I have not tested but I assume it wouldn’t last long)

  • I have been using Traxxas Titan 21T motors in my kids toys for awhile, these were the first aftermarket motor I used since I was familiar with them from RC cars. These give a nice ~50% speed boost over stock motors but draw a lot more current, you will need to upgrade the stock throttle plunger and gear selector eventually. I have melted a few plungers and gear selectors just running these motors at 12V (Actual voltage 14V).

• Aliexpress “RCX2” Titan 21T (These are really cheap and knock off from Traxxas, just don’t buy them)

  • I bought these to test for I believe $7 each, never had a problem at 12V actually, they ran for a very long time and are still in a Power Wheels Jeep. They performed just as well as the legitimate Traxxas Titan 21T motors. It is only a little more to buy from and support Traxxas so that is who I buy from.

• Traxxas Titan 775 10T

  • These are slow at 12V, but they will last indefinitely. I estimate that these motors are about 4MPH vs. the stock 5MPH at 12V. There have been in the kids Dream Camper all summer, I left them at 12V with 775’s because all of the kids will pile into it and I didn’t see the stock 550’s lasting long.

18V / 20V (DeWalt is still 18V even though they say 20V)

• Stock Power wheels 550

  • These run fine but do seem to wear out rather quick at 18V, I find stock motors at 18V is about the same speed as Traxxas 21T motors at 12V so I just run Traxxas motors at 12V

• Traxxas Titan 21T

  • These seem to wear out faster than stock motors at 18V, but are about 100% faster (Double the speed) of stock motors at 12V. I don’t have a large sample size of motors tested at 18V, but I end up having to limit the current with my ESC to keep the brushes from smoking.

• Aliexpress “RCX2” Titan 21T

  • Nope, these will make it about 100 feet… Only tested two but both seized up nearly immediately, once they cooled and were free again I tried again and they just locked up for good. These were broken in motors that ran fine at 12V.

• Traxxas Titan 775 10T

  • Anything under 24V will last a long time, nothing more to be said.

24V

• Traxxas Titan 775 10T

  • I have been running these at 24V for awhile, no issues at all. About the same speed as the 21T 550 motors at 18/20V. I have not had to limit the current to keep the brushes from over heating.

• ML Toys 775 Performance Motors (Not their new Beta Motors)

  • I recently (Less than a month) installed a pair into my sons Bravo Gravedigger with four-wheeler treads on the rear tires. I am finding these are about the same speed as the Traxxas Titan 775 10T, I believe a little higher RPM. I am having to limit the max current a bit to keep the brushes from over heating, more than I have with the Traxxas, but, this is on a grave digger with four-wheeler tires. These are taking a lot of power so far.

• AndyMark 775 RedLine Motor (Not tested yet)

  • I have heard this is the best value performance motor, I have not bought any to test yet.

30V

• Traxxas Titan 775 10T

  • My son has driven me around the lawn up hills with these motors at 30V (Actual operating voltage of about 33V with a 30AH LiFePO4 battery in series with 6AH 20V DeWalt battery) in the Barbie Dream Camper, combined weight of my son and I is about 220 pounds and the Dream Camper is one of the heavier vehicles on the market. Even comes with a soft start feature from the factory (that has been bypassed awhile ago for variable speed controller testing). I did end up having one of the motors overheat and melt the fan blades after a bit of use so I put my son back on 24V.

36V - I have not tested 36V battery setups yet with any motors, 30V has been enough speed for now.

Motor Break-In Procedure

NOTE: Breaking in aftermarket motors is extremely important if you don’t want them to catch on fire, the brushes do burn when hot enough and you will have to spend all the time replacing them again. I had two 775 motors burst into flames because I didn’t break them in properly, don’t make that mistake.

Breaking in brushed DC motors, such as 550 and 775 motors, can enhance their performance, efficiency, and lifespan. The break-in process involves gradually seating the brushes to the commutator, ensuring better contact and reducing wear over time.

First step is to follow the motor manufactures guidelines in how to break in the motors. If none are provided, here is the procedure I regularly use with excellent success (when followed…)

Recommended Break-In Procedure

The most common method is the low-voltage, no-load break-in process, which is simple and effective.

Tools Required

• Power supply (variable DC power supply is ideal) or a low-voltage battery.

• Wires and connectors to safely connect the motor to the power supply.

Steps for Dry Break-In

1. Set Up the Motor:

   • Ensure the motor is securely mounted or held in place to prevent it from moving during the process. A good option is to mount into the gear boxes with no pinion gear installed.

2. Apply Low Voltage:

   • Connect the motor to a low voltage source, typically 6V for 550 motors and 12V for 775 motors (no more than 50% of the motor's rated voltage).

     • If you do not have a power source that is half of your operating voltage, wire the motors into the car and run on low speed. Low speed will wire the motors in series so the voltage should be roughly half across each motor.

   • Allow the motor to run without any load attached (no gears or wheels).

3. Run Time:

   • Let the motor run for 25 minutes at the low voltage. This allows the brushes to gradually conform to the commutator's surface. (This is the step that is the most difficult to adhere to, make sure you run for at least 25 minutes, it does take that long.)

4. Check for Smooth Operation:

   • Ensure the motor runs smoothly and without excessive noise or sparking at the brushes.

   • Stop the process if excessive heat or unusual noises occur.

Post Break-In Steps

1. Inspect the Motor:

   • Check the brushes and commutator for even wear and smooth contact.

   • Look for any debris inside the motor housing.

2. Run Under Light Load:

   • Gradually test the motor under light load before full-load operation to ensure everything functions correctly. Install the motors into the gear boxes and install in the vehicle. Lift the rear tires off the ground and test in low first. There should be very minimal arcing (sparks) coming from the motor. Now test is high gear. If excessive arcing is observed, let run for another 10 minutes with the wheels listed off the ground and it should go away. If it does not, the motors may have a defect, remember, brushed motors do arc, you are looking for excessive amounts of arcing and a motor that isn’t running smoothly.

3. Maintain the Motor:

   • Periodically clean and inspect the brushes and commutator for continued smooth operation.

The above procedure is what I follow for all motors, both 550’s and 775’s and have had good success. There is another common method using distilled water, I have never done it so I won’t include any details on it.

Conclusion

Choosing the right motor upgrade for your kids' ride-on car depends on your specific needs, whether it's more speed, torque, or durability. While this article focused on the differences between 550 and 775 motors, there’s plenty more to consider as you plan your modifications. One key aspect I didn’t cover here is pinion gear selection—be sure to research the correct shaft diameter and gear pitch to ensure compatibility with your drivetrain.

Motor upgrades can transform your ride-on vehicle, but careful planning and research will ensure your modifications are safe, efficient, and provide the performance boost you’re looking for.