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RC Gear Ratio & Reference
Enter pinion/spur teeth and motor specs to get output torque and shaft speed, plus reference tables for typical RC gear ratios and radio systems.
gear ratio → torque & rpm calculator
Overall gear ratio — spur ÷ pinion
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Output torque — at the spur/wheel shaft
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Output speed — spur/wheel shaft RPM
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reference
typical overall gear ratio by vehicle class
| Vehicle / use | Typical ratio |
|---|---|
| 1/8 buggy or truggy (brushless) | 2.4 – 3.2 : 1 |
| 1/10 buggy / short course (brushless, 2S) | 6.5 – 9.0 : 1 |
| 1/10 on-road / touring (brushless) | 5.0 – 7.0 : 1 |
| 1/10 monster truck / basher (brushed) | 9.0 – 15.0 : 1 |
| Scale rock crawler (w/ internal gearbox) | 20 – 40+ : 1 |
| 1/5 large-scale (gas or big brushless) | 4.0 – 6.0 : 1 |
Rough starting points only — actual ratio depends on motor kV, wheel diameter, battery voltage, and whether you're tuning for top speed or low-end torque.
common pinion / spur combinations
| Pinion | Ratio w/ 87T spur | Ratio w/ 100T spur |
|---|
rc radio & transmitter reference
| Band | Notes |
|---|---|
| 27 MHz | Older toy-grade gear, fixed crystal channels, short range |
| 72 MHz | Legacy hobby-grade (surface only, US), numbered channels, crystal swap needed to avoid interference |
| 2.4 GHz | Current standard for nearly all RC systems — frequency-hopping spread spectrum, no crystal, auto-binds per transmitter |
Servo pulse width
1000–2000 µs (1500 µs = center)
Typical servo/receiver frame rate
~50 Hz
PPM
All channels on one wire, time-multiplexed (~8ch typical limit)
S.BUS / SBUS
Digital serial bus, up to 16–18ch on one wire
Typical channel counts
4ch (car/boat) · 6–8ch (plane/heli) · 16ch+ (advanced)