Axial SCX10 Brushless Gearing Guide — FDR, Pinion & Spur Chart

Axial SCX10 Brushless RC Gearing & Optimization Guide

Optimizing your gear ratio is one of the most effective ways to balance speed, torque, and electronics longevity in your Axial SCX10 III (Brushless Conversion). The relationship between your pinion gear (attached to the motor) and your spur gear (attached to the transmission) dictates how hard your motor has to work — and on a 1/10 rock crawler & scale trail truck platform with a 43.2 internal transmission ratio, even a single-tooth pinion change shifts your final drive ratio by 3-5%.

A brushless-converted SCX10 III typically pairs a 1800-2400Kv sensored crawler motor with a purpose-built crawler ESC that offers programmable drag brake, punch curve, and LiPo low-voltage cutoff. On 3S LiPo the platform delivers noticeably faster trail speeds than the brushed configuration without giving up crawling finesse — as long as the ESC is programmed for smooth low-throttle response rather than raw punch.

Rock Crawler & Trail Truck Drivetrain Notes for the Axial SCX10 Brushless

Ultra-low speed crawling on a Axial SCX10 Brushless demands heavy grease packed into the portal or straight axles to damp shock loading and keep the ring-and-pinion quiet under sustained torque. Whether you are running a precisely tuned slipper clutch or a fully locked differential, the goal is to make the drivetrain deliver torque smoothly instead of shock-loading it into a rock face. High-torque binds against a ledge can spike amp draw well past continuous ratings and overheat the motor even at walking pace, so a small in-line wattmeter or an ESC with current logging is worth more than another temperature reading — heat shows up long after the damage is already done.

🛠️ Essential Tools Required for Gearing Changes

Hex drivers (1.5mm, 2.0mm, or 2.5mm depending on the Axial SCX10 Brushless variant)
Paper strip (for setting precise gear mesh)
Infrared temperature gun (crucial for monitoring motor heat after each run)
Threadlock (for the pinion gear grub screw)
Pinion gear puller (recommended when swapping gears on a hot motor shaft)

📋 Comprehensive Gearing & Temperature Guide

1. Understanding Pinion vs. Spur Gear Adjustment

Changing your gears alters your final drive ratio. Installing a larger pinion gear or a smaller spur gear increases top-end speed but increases the load on the motor, causing it to run hotter. Conversely, a smaller pinion or larger spur increases torque and acceleration while lowering top speeds and keeping your motor cool. On the Axial SCX10 Brushless, this trade-off is amplified by the fixed 43.2 internal ratio — small external changes have a direct thermal consequence.

2. How to Set a Perfect Gear Mesh

Improper gear mesh will quickly strip your spur gear or bind your drivetrain.

Loosen the motor mount screws slightly.
Place a small strip of standard notebook paper between the pinion and spur gear teeth.
Press the gears tightly together and tighten the motor mount screws.
Roll the paper out. The paper should have clean, crisp crinkles without ripping.

Recommended Pinion & Spur Chart

All combinations use a 56T 48-pitch spur. FDR is calculated as (spur ÷ pinion) × 43.2 internal ratio.

Pinion	Spur	FDR	Typical Use
11T	56T	219.93	High-bite carpet / tight indoor
13T	56T	186.09	High-bite carpet / tight indoor
15T	56T	161.28	High-bite carpet / tight indoor
17T	56T	142.31	High-bite carpet / tight indoor
19T	56T	127.33	High-bite carpet / tight indoor

Understanding Pinion & Spur Gears

Most brushless SCX10 conversions retain the 13T pinion / 56T spur. Motor Kv choice matters more than pinion size on this platform: 1800Kv keeps crawling character, 2400Kv opens up trail speeds, and anything above 2500Kv starts to lose fine throttle control.

Rollout Targets

Brushless conversions keep the same portal-free solid-axle rollout in the fractions-of-an-inch range. Adding voltage does not shorten rollout — it just increases the top-end envelope.

Motor Temperature Management

Sensored brushless crawler motors on the SCX10 should stay under 160F (71C). Higher temps almost always indicate a drag brake percentage set too high, forcing the motor to work at zero throttle. A capacitor pack on the ESC input smooths high-torque transients on 3S LiPo.

⚠️ Critical Safety & Temperature Warning

Always use an infrared thermometer to check your motor and ESC temperatures during a run. RC electric brushless motors should never exceed 160°F (71°C). Exceeding 180°F (82°C) risks permanently demagnetizing your motor rotor and frying your Electronic Speed Controller. If your Axial SCX10 Brushless is running above these thresholds, you must "gear down" by installing a smaller pinion gear immediately, improve airflow with a larger motor fan, and inspect the drivetrain for binding.

Calculate a custom FDR for your Axial SCX10 Brushless

The link below opens the calculator with Custom / Other Chassis pre-selected, the Axial SCX10 Brushless's internal ratio of 43.2 and its recommended battery of 3S LiPo (11.1V) already set — just plug in your pinion, spur, motor, and tire to see top speed, runtime, and FDR for your exact setup.

Open calculator with 43.2 ratio + 3S LiPo (11.1V) preset →

⚡ Brushless, ESC Programming & LiPo Care for the Axial SCX10 Brushless

Brushless setups on the Axial SCX10 Brushless shift the tuning burden away from the motor itself (which has no brushes or comm to wear) and onto ESC programming and LiPo pack management. At 3S and above, the ESC settings you never touch are almost always the reason a brushless motor dies early.

1. ESC programming that actually matters

Timing — leave at low or factory for bashing. High-timing profiles gain top speed but add 15-25F to the motor at the same pinion. Racing only.
Punch / throttle profile — drop from linear to soft on high-Kv sensorless setups; the softer curve reduces peak current draw off the line and dramatically lowers ESC temperature over a pack.
Drag brake — set as low as the driving style allows. High drag brake on a crawler holds the motor actively at zero throttle, which is how sensored crawler motors overheat without ever moving.
LiPo cutoff — set to 3.2V or 3.3V per cell. This is the single most important pack-preservation setting and is why LiPo packs die from over-discharge.

2. Sensor cables and capacitors

Sensored setups on the Axial SCX10 Brushless are only as reliable as the sensor cable — inspect for chafing at every re-body and replace at the first sign of insulation wear. On 4S and above, add a dedicated capacitor pack to the ESC power input; the extra bulk capacitance flattens voltage spikes on hard-throttle transients and is the difference between a five-year ESC and a warranty claim.

3. LiPo care and storage

Storage voltage — 3.80-3.85V per cell. Never leave a pack fully charged for more than 24 hours.
Balance charge every cycle. Cell drift is the leading cause of pack retirement, and a fast charger's balance step catches it before it becomes dangerous.
Retire the pack when it puffs visibly, when internal resistance climbs above 12-15 mΩ per cell, or when usable capacity drops below 80% of rated. Puffed packs are a fire risk — discharge and dispose properly, do not "just one more run" them.
Never charge a warm pack. Let it drop to ambient before plugging it into the charger.

Rule of thumb on the Axial SCX10 Brushless: brushless motors do not "wear out" the way brushed motors do — they die from heat, from ESC settings, or from LiPo abuse. Fix those three and the motor outlasts the truck.

Axial SCX10 III (Brushless Conversion) Gearing Guide