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RC cars and trucks

Work out the setup before you run it

Fifteen calculators for gearing, speed, batteries and chassis, built around the numbers your manual gives you. Start from a stock vehicle or type your own.

Everything runs in your browser. No account, nothing uploaded. Results are for planning, not a promise of measured performance.

Gearing & speed

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Ratios, rollout, and what the car should theoretically do.

Gearing & theoretical speedMotor RPM, wheel RPM, FDR, and rollout in one setup.
FDR & rolloutCompare gearing without motor or battery inputs.
Target pinionFind required FDR and candidate tooth counts for a target speed.
Tire size & gearingCompare tire diameters and preserve rollout with corrected gearing.
GPS speed comparisonCompare measured speed and save each pass with its setup snapshot.
Compare A & BSee changed inputs, speed, gearing, and rollout against a baseline.

Power & battery

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Voltage, runtime, current, and pack combinations.

Voltage & energyReference pack voltage, rated watt-hours, and your own cutoff.
RuntimeMinutes from capacity, a usable fraction, and average draw.
Current, power & ESCInput power, claimed pack current, and a continuous rating target.
Matched packsSeries and parallel combinations of identical packs.

Chassis & setup

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Weight, springs, axles, and bench conversions.

Crawler reduction & overdriveShared reduction stages, axle ratios, and unequal tire sizes.
Corner & cross weightsFront, left, and diagonal balance from four scale readings.
Spring & suspensionSpring rate, wheel rate, and undamped corner frequency.
Nitro pit timingEstimate fuel runtime and a pit interval with reserve.
Servo conversionsConvert torque ratings and estimate travel time at rated speed.
Scale dimensions & speedModel dimensions and explicitly chosen scale-speed conventions.