What you need to know before you start building
Building an RC car means buying individual parts — motor, chassis, wheels, battery, receiver, transmitter — and assembling them yourself rather than buying a pre-built model. You will need basic tools (screwdrivers, pliers, a soldering iron for some builds), some mechanical knowledge, and time to learn how components fit together. The process takes anywhere from a few hours to several days depending on the complexity of your design and how familiar you are with electronics and mechanics.
The main advantage is cost: a custom-built car often costs less than a comparable ready-to-run model, and you learn exactly how each part works. The main disadvantage is that nothing comes pre-tuned or tested — if something does not work, you have to diagnose and fix it yourself. This guide covers the parts you will need, how to choose them, and the basic assembly steps.
Key Takeaways
- An RC car build requires a chassis, motor, speed controller, battery, receiver, transmitter, wheels, and suspension parts — each chosen based on whether you want on-road or off-road performance.
- Motor size (measured in turns) and battery voltage determine how fast your car will go; mismatching them can damage the motor or controller.
- Soldering connections between the battery, speed controller, and motor is standard practice and requires a soldering iron and solder.
- Assembly order matters: install the motor and gearbox first, then the suspension, then the electronics, so you can test each stage.
- Your first build will run better if you start with a proven chassis design rather than designing your own frame.
Choosing a chassis and deciding on-road versus off-road
The chassis is the frame and structural base of your car. It determines whether your build will be fast on pavement (on-road) or handle rough terrain (off-road). On-road chassis are low, stiff, and designed for smooth surfaces; off-road chassis sit higher, have longer suspension travel, and are built to absorb bumps.
For your first build, buy a chassis kit rather than designing one. Kits come with the frame, suspension arms, and mounting points already engineered. Popular beginner chassis include the Tamiya TT-02 (on-road touring car), the Tamiya TT-02B (off-road buggy), and the WLtoys 144001 (budget off-road). Each kit includes instructions that show where every part bolts together. Buying a kit also means replacement parts are widely available if you break something later.
On-road cars are faster and easier to control but require smooth surfaces. Off-road cars are slower but more forgiving on grass, dirt, and gravel. If you are unsure, start with an off-road chassis — they are more fun for learning because the terrain is more forgiving when you make mistakes.
Selecting motor, speed controller, and battery as a matched set
The motor, speed controller (ESC), and battery must work together. A motor is rated in "turns" — lower turn numbers (like 17T or 21T) spin faster and draw more power; higher turn numbers (like 45T or 55T) spin slower and draw less power. The speed controller handles power delivery from the battery to the motor. The battery voltage determines the motor's top speed.
A common beginner setup is a 17-turn brushed motor, a 60-amp speed controller, and a 2S LiPo battery (7.4 volts). This combination produces moderate speed and is forgiving if you make wiring mistakes. If you pair a 17-turn motor with a 3S battery (11.1 volts) without upgrading the speed controller, you risk burning out the controller. Always check the motor's recommended voltage range and the speed controller's maximum voltage before buying.
Brushless motors (which use electronic commutation instead of brushes) are faster and more efficient but require a brushless-compatible speed controller and are harder to troubleshoot if something fails. For your first build, a brushed motor is simpler and more forgiving. LiPo batteries are standard because they are light and hold charge well, but they require a LiPo-specific charger and careful handling — they can catch fire if overcharged or damaged.
Receiver, transmitter, and steering servo setup
The transmitter is the remote control you hold. The receiver is the circuit board inside the car that listens to the transmitter's signal. The servo is a small motor that turns the steering linkage left and right. These three components must be compatible — a 2.4 GHz receiver will not work with a 27 MHz transmitter, for example.
Most modern RC cars use 2.4 GHz frequency-hopping systems, which are reliable and do not interfere with each other even if multiple people are driving nearby. Popular receiver brands include Spektrum, FrSky, and Flysky. When you buy a receiver, it usually comes with a transmitter already bound to it (meaning they recognize each other). If you buy them separately, you will need to bind them yourself — the receiver manual will have binding instructions.
The servo connects to the receiver's steering channel. A standard servo for a small car draws about 6 volts and moves 60 degrees in either direction. Make sure the servo is rated for the voltage your battery provides. The servo connects to the steering linkage (usually a plastic rod or metal rod) that physically turns the front wheels.
Wheels, tires, and suspension components
Wheels come in different widths and offsets (how far they stick out from the chassis). Tires come in different compounds — soft tires grip better but wear faster, hard tires last longer but slip on smooth surfaces. For on-road cars, use hard compound tires on pavement. For off-road cars, use soft or medium compound tires on dirt and grass.
Suspension parts include shock absorbers (which dampen bouncing), suspension arms (which hold the wheels in place), and springs (which control how stiff the suspension feels). Most chassis kits include these parts, but you may want to upgrade them later. Stiffer springs make the car handle better on smooth surfaces; softer springs absorb bumps better on rough terrain.
Wheel size affects speed and torque. Larger wheels are faster but require more motor power. Smaller wheels are slower but easier to accelerate. For a beginner build, use the wheel size recommended in your chassis kit instructions.
Tools and materials you will need
Basic tools include a Phillips head screwdriver, a flathead screwdriver, needle-nose pliers, and a hex key set (usually included with the chassis kit). You will also need a soldering iron (25 to 40 watts), solder (lead-free or lead-based, both work), and a damp sponge to clean the soldering iron tip between joints.
A multimeter (a device that measures voltage and continuity) is useful for troubleshooting but not required for assembly. A small hobby knife helps trim plastic parts. Threadlocker (a liquid that prevents screws from loosening) is optional but recommended for screws that vibrate during use — explore a small drop to the screw threads before installing.
You will also need a LiPo charger if your battery does not come with one. Do not use a regular battery charger — LiPo batteries require a charger that monitors each cell's voltage separately. A basic LiPo charger costs between $20 and $50.
Assembly order and testing each stage
Assemble in this order: (1) install the motor and gearbox into the chassis, (2) attach the suspension arms and wheels, (3) install the battery tray and find the battery, (4) solder the battery connector to the speed controller, (5) connect the speed controller to the motor, (6) mount the receiver and servo, (7) connect the servo to the receiver's steering channel, (8) connect the speed controller to the receiver's throttle channel, (9) bind the receiver to the transmitter, (10) test steering and throttle on a flat surface before driving.
After step 2, spin the wheels by hand to make sure they turn freely and the suspension moves smoothly. After step 5, connect the battery and listen for a beep from the speed controller — this confirms power is reaching it. After step 8, turn on the transmitter, then the receiver, and move the steering stick to confirm the wheels turn. Move the throttle stick and listen for the motor to spin (do not let the wheels touch the ground during this test).
If the motor spins backward when you push the throttle forward, reverse two of the three wires connecting the motor to the speed controller. If the steering does not respond, check that the servo connector is fully seated in the receiver's steering channel. These small tests catch problems before you take the car outside.
Common mistakes and how to avoid them
The most common mistake is soldering the battery connector backward, which will destroy the speed controller when ready. Before soldering, double-check the polarity: red wire to positive, black wire to negative. Take a photo of the connector before you desolder it so you know which way it goes.
Another common mistake is over-tightening screws, which strips the plastic threads in the chassis. Tighten screws until they are snug, then stop — you should not need to force them. If a screw is hard to turn, back it out and check that the part is aligned correctly.
A third mistake is running the battery completely flat, which damages LiPo cells and shortens battery life. Most speed controllers have a low-voltage cutoff that stops the motor when the battery drops below a safe level, but this only works if you set it correctly. Check your speed controller manual for the cutoff voltage (usually 3.0 volts per cell for a 2S battery).
Frequently Asked Questions
Do I need to solder, or can I use connectors instead?
Soldering is the standard method because it creates a stronger, lower-resistance connection than most connectors. If you are uncomfortable soldering, you can buy pre-soldered battery connectors and speed controller connectors, then connect them together using XT60 or Deans connectors. This takes longer and costs more, but it works.
What is the difference between brushed and brushless motors?
Brushed motors use carbon brushes to switch current direction; they are simpler, cheaper, and easier to repair. Brushless motors use electronic switching; they are faster, more efficient, and last longer. For a first build, brushed is better because it is more forgiving if you make mistakes. Brushless is worth learning later once you understand how RC cars work.
Can I use a regular battery charger for my LiPo battery?
No. LiPo batteries have multiple cells that must be charged separately to prevent overcharging one cell and causing a fire. You must use a charger designed for LiPo batteries. A basic LiPo charger costs $20 to $50 and will last for years.
How long does a build usually take?
A beginner build with a chassis kit typically takes 4 to 8 hours spread over one or two days. Most of this time is reading instructions, finding the right parts, and double-checking connections. If you rush, you will make mistakes that take longer to fix later.
What should I do if the motor does not spin when I connect the battery?
First, check that the battery is charged. Second, check that the speed controller's low-voltage cutoff is not triggered (the manual will explain how to reset it). Third, check that the motor wires are soldered correctly to the speed controller. Fourth, use a multimeter to confirm the battery is outputting voltage. If none of these work, the speed controller or motor may be damaged.