Every basher hits the same moment. The truck that felt fast at Christmas now feels like it is jogging, and the internet is yelling three things at you: go brushless, go 3S, go 6S. Some of that is great advice. Some of it is how people end up at our repair bench holding a bag of stripped spur gears and a puffy ESC.
Here is the upgrade path we actually recommend, in the order that gives you the most speed per dollar without blowing anything up. We will cover what brushed and brushless really mean, what the "S" number on a LiPo changes, how a motor's Kv rating turns voltage into RPM, and where 6S fits (spoiler: it is a different truck, not a bigger battery).
The Short Answer
Brushless beats brushed for speed, efficiency and maintenance, but battery voltage is what really sets top speed: each LiPo cell adds about 3.7 volts, so going from 2S to 3S is roughly a 50 percent jump in voltage, and you should only do it when both the ESC and motor are rated for 3S.
- Step 1: swap a brushed system for a matched brushless ESC and motor combo.
- Step 2: move to 3S only if every part in the power chain is rated for it, and gear down or watch temperatures.
- 6S belongs in vehicles designed for it, like 1/8-scale bashers. It is not a bolt-on for a 1/10 truck built for 3S.
- The weakest link sets your limit: the lowest rated part (ESC, motor or drivetrain) is your real maximum.
1. Brushed vs Brushless: What Changes When You Swap
A brushed motor uses carbon brushes pressed against a spinning commutator to switch current through the coils. As Horizon Hobby puts it, the brushes "have to make direct physical contact with the commutator." Contact means friction, friction means heat and wear, and eventually the brushes wear out. A brushless motor moves that switching job into the electronic speed control (ESC), so nothing rubs.
Why brushless is the first upgrade
Horizon Hobby lists the payoffs: brushless motors are more efficient because less energy turns into brush heat, need much less maintenance and generally last much longer. In real life that shows up as more punch, more run time from the same pack and a motor you mostly forget about. The catch is cost, and you are buying an ESC and motor together because a brushed ESC cannot run a brushless motor.
Why brushed still has a place
Brushed systems are cheap, simple and forgiving. They are great for first trucks, kids' trucks and crawlers where low-speed control matters more than top speed. If your brushed truck is your first RC, drive it until you are bored, learn to fix it, then upgrade. You will know which parts break before you double the power going into them.
Buying a combo vs separate parts
For a first conversion, buy a matched ESC and motor combo sized for your vehicle's scale and weight, such as a 1/10 combo for a 1/10 truck. You skip the guesswork on connectors, timing and compatibility. Check the motor shaft diameter, the mounting pattern and the battery connector before you order, and plan on a different pinion gear.
2. 2S vs 3S vs 6S: What the Cell Count Really Does
The "S" is the number of LiPo cells in series. Each cell is 3.7 volts nominal, which is why the Traxxas Rustler 4X4 VXL manual lists its VXL-3s ESC's input as up to 11.1V (2S to 3S LiPo), and an ARRMA 6S manual lists 14.8 to 22.2 volts for 4S or 6S packs. Fully charged, a LiPo cell sits at 4.2 volts. The ARRMA manual says to use fully charged packs at 4.2V per cell, which matches the Battery University standard for lithium cells.
| Pack | Nominal voltage | Fully charged | Velineon 3500Kv, theoretical no-load RPM (Kv x nominal volts) |
|---|---|---|---|
| 2S LiPo | 7.4V | 8.4V | about 25,900 |
| 3S LiPo | 11.1V | 12.6V | about 38,850 |
| 4S LiPo | 14.8V | 16.8V | not rated for it |
| 6S LiPo | 22.2V | 25.2V | not rated for it |
How Kv turns volts into speed
A brushless motor's Kv rating is its no-load RPM per volt (motor constants). Multiply Kv by voltage and you get a theoretical no-load RPM, not a measured number. For a 3500Kv Velineon, that works out to about 25,900 RPM at 2S nominal (3500 x 7.4) and about 38,850 at 3S nominal (3500 x 11.1). Under load, the real number is lower, but the ratio is the point: about 50 percent more voltage means about 50 percent more potential RPM. That is why 3S feels like a different truck.
What the manufacturer says about speed
The Rustler 4X4 VXL owner's manual lists 65+ mph only with a 3S LiPo and optional 20/54 gearing that is sold separately; the truck ships with 11/54 gearing. Notice the gearing note. Top-speed claims nearly always assume a specific pinion, a fresh pack and a long, smooth run.
The weakest link rule
Every part in the power chain has a cell limit, and the lowest one wins. A good example: the Castle Mamba X SCT Pro combo's ESC handles 2S to 6S, but Big Squid RC notes its 1410 motor is listed for 2S or 3S. The ESC could take 6S. The motor should not. Check the ESC, the motor and the vehicle's manual before you plug in a bigger pack.
3. The Speed Upgrade Path (and Where It Goes Wrong)
Here is the order we recommend. Each step should be fully sorted out (gearing, temperatures and broken parts) before you take the next one.
| Stage | Setup | What you get | Check before you buy |
|---|---|---|---|
| 0 | Brushed motor, NiMH or 2S LiPo | Cheap, simple fun | ESC must have a LiPo cutoff before you use LiPo |
| 1 | Brushless system on 2S | More punch, more run time, far less motor maintenance | ESC and motor ratings, motor mount, connectors |
| 2 | Same brushless system on 3S | The big jump in speed | Both ESC and motor rated for 3S; gearing; drivetrain |
| 3 | A 6S-designed vehicle | Big 1/8-scale power | This is a new truck, not an add-on |
Step by step
- Know your ratings. Write down the ESC's cell limit, the motor's limit and what the vehicle manual allows.
- Go brushless on 2S first if you are coming from brushed. Run a few packs and check motor and ESC temperatures after each one.
- Fix what breaks. More power finds weak driveshafts, spur gears and servos fast. Upgrade those before adding voltage.
- Step to 3S only with 3S-rated parts. Start with the stock or a smaller pinion, not the speed pinion.
- Check temps after a few minutes. If the motor is too hot to hold a finger on, gear down.
- Stop there unless you are shopping for a 6S-designed vehicle.
Gear down when you go up
More voltage with the same gearing loads everything harder. For heavy loads, ARRMA's manual says to alter the gear ratio with a smaller pinion or a larger spur gear. When you step from 2S to 3S, start conservative. You will still be dramatically faster, and your motor and ESC will thank you.
Why 6S is a different truck
A 1/10 truck built for 3S has driveshafts, diffs, gears and suspension sized for that power. Doubling the voltage multiplies the stress on all of it. 6S power systems also live in bigger 1/8-scale vehicles that are designed around them from the start, with heavier drivetrains and room for big packs. If you want 6S, buy a truck built for it. Your 1/10 basher will be happier on 3S.
Do not forget the charger and packs
Every step up needs batteries and a charger that match: correct cell count, a connector your ESC uses and a LiPo balance charger. LiPo packs also need a low-voltage cutoff in the ESC. Most modern brushless ESCs include it, but confirm it is enabled.
Conclusion
The cheapest speed is not always the smartest speed. Go brushless first, learn your truck on 2S, reinforce the parts that break, then step to 3S with parts rated for it. When 3S is not enough, that is your sign to look at a 6S-designed vehicle, not a bigger pack for the old one.
Want help matching a motor, ESC, pinion and battery to your truck? Stop by our Cumming showroom and we will check your ratings with you, or browse our motors and ESCs and LiPo batteries.
Gear Mentioned in This Guide
Traxxas Velineon 3500 Brushless Motor (3351R)
The 3500Kv sensorless motor Traxxas uses in its VXL 1/10 trucks.
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Spektrum Firma 85A Smart ESC / 3300Kv Motor Combo
A matched brushless ESC and motor combo for converting a 1/10 brushed truck. Check its cell rating against your plans.
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Castle Mamba X SCT Pro Sensored ESC / 1410-3800Kv Combo
A sensored brushless combo. The ESC handles more cells than the motor, so read both ratings.
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Traxxas Titan 550 12T Brushed Motor (3785)
The brushed motor many Traxxas owners start with. Cheap, simple and replaceable.
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Traxxas 3S 5000mAh 11.1V 25C LiPo with iD (2872X)
A 3S pack for 3S-rated Traxxas trucks like the Rustler 4X4 VXL.
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ARRMA 1/8 Kraton 6S BLX 4WD
A truck designed around 6S from day one, which is the honest way to get there.
Shop nowFrequently Asked Questions
Is brushless always faster than brushed?
Not automatically, but in practice yes. Brushless systems are more efficient and handle more power, so a brushless truck on the same battery is usually quicker and runs longer. Brushed motors are still fine for beginners, kids and crawlers where low cost and smooth low-speed control matter more.
Can I put a 3S battery in a 2S RC car?
Only if the ESC and the motor are both rated for 3S. Check the manual for both. Many brushed systems are limited to 2S LiPo. Running more cells than a part is rated for can destroy the ESC or motor quickly.
How much faster is 3S than 2S?
A 3S pack has 11.1 volts nominal versus 7.4 volts for 2S, about 50 percent more. A brushless motor's theoretical no-load RPM scales with voltage, so potential speed rises by a similar proportion with the same gearing. Real top speed depends on load, gearing, aerodynamics and the battery.
What does Kv mean on a brushless motor?
Kv is the motor's no-load RPM per volt. In theory, a 3500Kv motor on 11.1 volts would spin about 38,850 RPM with no load (3500 x 11.1); under load it turns slower. Higher Kv means more RPM per volt, but also more current draw and heat when the motor is loaded.
Can I run 6S in my 1/10 basher?
Only if the manufacturer rates every part for it, which few 1/10 bashers are. 6S is usually found in 1/8-scale vehicles designed around it. Putting 6S in a truck built for 3S overloads the ESC, motor and drivetrain.
Do I need a new charger to go to 3S?
You need a LiPo balance charger that supports the cell count you are charging and the right connector or adapter. Many chargers handle 2S through 4S or more, but check yours before you buy 3S packs.
