The simplest way to make a brushed motor faster is to increase the voltage supplied to it, since speed is directly proportional to voltage. But voltage is just the starting point. A combination of reduced internal friction, better brush-to-commutator contact, timing adjustments, and proper maintenance can squeeze significantly more RPM out of the same motor without replacing it.
Increase Input Voltage
Brushed DC motors follow a straightforward rule: more voltage equals more speed. If you’re running a motor at half its rated voltage, you’re getting roughly half its potential RPM. Moving from a 7.2V battery pack to an 8.4V pack, for example, gives you a proportional bump in top speed.
The catch is heat. Every motor has a voltage rating, and exceeding it pushes more current through the windings, generating extra heat that degrades the insulation on the wire and accelerates brush wear. A modest overvolt of 10 to 20 percent is common in RC and hobby applications, but you’ll want to monitor motor temperature by touch after runs. If it’s too hot to hold comfortably (above roughly 160°F or 70°C), you’re shortening its life. Running a small fan or adding airflow ducts helps if you’re pushing voltage limits.
If you’re using a speed controller with PWM (pulse width modulation), keep in mind that a 50% duty cycle delivers an average voltage of half the supply. So your effective speed depends on both the battery voltage and the throttle signal reaching the motor. A higher-voltage battery paired with the same throttle percentage will spin the motor faster at every point in the range.
Advance the Motor Timing
Most hobby-grade brushed motors have an adjustable endbell that lets you rotate the brush assembly relative to the magnets. This is called timing, and it directly affects where in the rotation the motor gets its power pulse.
Advancing the timing shifts peak power output to higher RPM. This means you sacrifice some low-end torque in exchange for a higher top speed. It’s a worthwhile trade if your application involves sustained high-speed runs, like an RC car on an oval track or a long straight. For heavier loads or situations requiring frequent hard acceleration from a stop, lower timing keeps more torque available where you need it.
The trade-off is temperature. The more you advance timing, the hotter the motor runs, because the brushes arc more aggressively against the commutator. Start with small adjustments (a few degrees at a time) and check motor temp after each session. If you’re racing, finding the sweet spot between top speed and thermal limits is where the real gains live.
Break In the Brushes Properly
A brand-new brushed motor has flat brush faces pressing against a curved commutator. That means only a thin line of each brush actually makes electrical contact. Breaking in the motor wears the brush faces into a matching curve, maximizing the contact patch. More contact area means lower electrical resistance, which translates to more efficient power transfer and measurably higher speed.
The water break-in method is the most popular technique among RC hobbyists. Fill a container with enough distilled water to fully submerge the motor. Connect it to a low-voltage source (2 to 3 volts) and let it run submerged for about 5 minutes. Then gradually increase speed over the next 5 to 10 minutes. The water carries away carbon and copper dust as the brushes seat, and you’ll see it turn murky. That discoloration is the material being removed as the brushes conform to the commutator’s shape.
After the break-in, remove the motor, dry it thoroughly, and hit it with motor spray cleaner to flush out any remaining debris and moisture. Finish by adding a drop of light bearing oil to each bushing or bearing. Skipping the drying and cleaning step risks corrosion, so don’t cut corners there.
Reduce Mechanical Friction
Every bit of drag inside the motor housing steals speed. The two biggest friction sources are the bearings (or bushings) and the brush springs.
If your motor uses bronze bushings, upgrading to ball bearings is one of the most effective single modifications you can make. Ball bearings dramatically reduce rotational drag compared to bushings, especially at high RPM. Many aftermarket bearing kits are designed as drop-in replacements.
For motors that already have bearings, lubrication matters. A light, low-viscosity oil on the bearings keeps them spinning freely. Thick grease creates more drag than thin oil at the speeds hobby motors typically reach. Sealed or shielded bearings are often lubricated for life and don’t need additional grease, but open bearings benefit from a small drop of bearing oil applied periodically. Avoid over-lubricating, as excess oil attracts dirt that turns into an abrasive paste.
Brush spring tension is the other factor. Stiffer springs press the brushes harder against the commutator, increasing friction. Some aftermarket springs are lighter, reducing drag at the cost of slightly less reliable contact at extreme RPM. This is a more advanced modification and only worth pursuing after you’ve addressed bearings and lubrication first.
Clean the Commutator
Over time, the commutator collects a layer of carbon buildup and oxidation that increases electrical resistance between the brushes and the copper segments. Cleaning it restores conductivity and recovers lost speed.
Use fine-grit sandpaper (600 grit or higher) to gently polish the commutator surface. You’re not trying to remove material, just the buildup. After sanding, flush the motor with isopropyl alcohol to wash carbon and copper dust out of the gaps between commutator segments. Those gaps need to stay clean because conductive debris bridging them creates partial short circuits that waste energy as heat.
A motor spray cleaner works well as a final rinse. Let everything dry completely before reassembling or running the motor. Making this a regular part of your maintenance routine, especially after every few hours of run time, keeps the motor performing closer to its break-in peak.
Choose the Right Wind Count
If you’re shopping for a replacement motor rather than modifying your current one, the number of turns on the armature winding is the single biggest factor in speed. A motor labeled “27 turns” has more wire wraps around each armature pole than a “17 turn” motor. Fewer turns means lower resistance, higher current draw, and faster RPM at any given voltage.
A lower-turn motor spins faster but draws more current, generates more heat, and drains batteries quicker. It also produces less torque per amp, so it’s better suited for lighter loads. A higher-turn motor is slower but more efficient and torquey. For maximum speed, go as low on turns as your battery and speed controller can handle thermally. For a balance of speed and runtime, a mid-range wind count is the practical choice.
Putting It All Together
Each of these modifications stacks. A properly broken-in motor with clean commutator, ball bearings, light oil, advanced timing, and a slightly higher voltage battery will be noticeably faster than the same motor straight out of the box on a stock setup. The order that gives you the most return for the least risk: start with a proper break-in, then upgrade to bearings if needed, clean the commutator, adjust timing in small increments, and increase voltage last since it’s the modification most likely to shorten motor life if overdone.