How to Make a High-Speed RC Car: Power, Gearing, Tyres and Aero
To make an RC car faster, go brushless (motor and ESC), raise the voltage within what the system is rated for (for example 2S to 3S LiPo), gear up in small steps while checking motor temperature, fit belted or speed-run tyres that don’t balloon, and lower and stabilise the car with aero and setup. Purpose-built speed-run cars such as the Traxxas XO-1 or Arrma Limitless show the recipe: lots of power, low drag and stability. Here’s the order to upgrade and the limits to respect.
By Kyle HilsonUpdated: October 20264 min read
Upgrade order for more speed
| Step | Upgrade | Speed gain | Watch out for |
|---|---|---|---|
| 1 | Brushless motor + ESC | Very large | Drivetrain strength, heat |
| 2 | Higher-voltage LiPo (within ESC/motor rating) | Large | ESC and motor limits, battery C rating |
| 3 | Gearing (larger pinion / smaller spur) | Medium | Motor and ESC temperature |
| 4 | Tyres (belted, low profile) | Medium | Ballooning, balancing |
| 5 | Aero and setup (lower ride height, wing, splitter) | Stability at speed | Ground clearance |
| 6 | Stronger drivetrain parts | Reliability | Cost |
Power: brushless and voltage
Brushless systems are far more efficient and powerful than brushed motors, which is why every fast car uses them. Choose a motor and ESC rated for the voltage you plan to run. Speed rises roughly with motor kV × voltage, so going from 2S to 3S on a suitable system raises top speed noticeably, but also current and heat. Use LiPo packs with enough C rating and good connectors (XT90, EC5 or similar on bigger cars).
Gearing and temperature
- Start with the manufacturer’s gearing for your voltage.
- Increase the pinion by one or two teeth at a time.
- After a short run, check motor temperature: as a common guideline, stay below about 70–80 °C on the motor can; check the motor maker’s limit.
- If temperatures climb, go back a step or improve cooling (fan, heatsink).
- Gear for the space you have: tall gearing needs a long straight to reach top speed.
Tyres and stability
- Belted tyres stop the tyre from ballooning (growing in diameter) at high RPM, which ruins handling and can tear tyres apart.
- Balance the wheels; vibration at speed loosens screws and breaks parts.
- Lower the ride height and stiffen the suspension for smooth surfaces.
- Aero: front splitter and rear wing keep the car planted; body shape matters at high speed.
- Steering: reduce steering throw (dual rate) for speed runs; small inputs at speed are dramatic.
Cars built for speed
| Car | Type | Notes |
|---|---|---|
| Traxxas XO-1 | 1/7 supercar, AWD | Marketed as a 100+ mph car out of the box (with the right setup) |
| Arrma Limitless | 1/7 speed-run roller | Sold without electronics for custom speed builds |
| Arrma Infraction / Felony | 1/7 street bashers | Fast on-road with 6S power |
| Touring cars with modified brushless | 1/10 on-road | Fast on tracks; light and precise |
Check current versions and claimed speeds on the makers’ sites; speed claims depend on batteries, gearing and conditions.
Safety for speed runs
- Use a large, empty, smooth area with permission, never public roads.
- Keep people well behind and to the side of the run.
- Check the fail-safe sets throttle to neutral/brake.
- Inspect tyres, wheel nuts and battery straps before every pass.
- Measure speed with GPS telemetry rather than guessing.
FAQ
What is the easiest way to make my RC car faster?
A brushless motor and ESC upgrade, then a higher-voltage battery the system supports, then small gearing changes with temperature checks.
Does a bigger pinion make an RC car faster?
Yes, top speed rises, but so does motor and ESC load. Check temperatures after each change.
Can I make a brushed RC car fast?
Only to a point; brushed motors overheat with tall gearing and high voltage. Brushless is the real step.
How fast can an RC car go?
Ready-made speed cars are marketed at 100+ mph; record speed-run cars go much faster.
More on this topic: the complete RC Cars guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
