RC Gear Ratio Calculator
Compare setups side by side and find the ideal pinion/spur combination.
Change Impact Chart
% change vs. your current setup. Click any cell to set it as the new setup.
| Spur ↓ Pinion → | 16T | 17T | 18T | 19T | 20T | 21T | 22T | 23T | 24T |
|---|---|---|---|---|---|---|---|---|---|
| 76T | |||||||||
| 77T | |||||||||
| 78T | |||||||||
| 79T | |||||||||
| 80T | |||||||||
| 81T | |||||||||
| 82T | |||||||||
| 83T | |||||||||
| 84T |
Change
0.0%
No change
Current
Gear Ratio
4.00:1
New
Gear Ratio
4.00:1
Free to start · iOS & Android
Setup App & Race Log
Save your gearing and the rest of your setup, get AI tuning answers, and log your races.
How to use this calculator
- • Enter your current pinion and spur tooth counts to establish a baseline.
- • Enter a new setup to compare, or click any cell in the chart to set it as the new setup.
- • Search for your car model to auto-fill the internal ratio.
- • Add rear tire diameter to calculate rollout — the distance traveled per motor revolution.
- • Positive change = higher ratio = more torque and acceleration.
- • Negative change = lower ratio = higher top speed, but more strain on the motor.
- • Want the actual mph? The RC speed calculator turns your gearing, motor KV, and voltage into a top-speed number.
- • Your settings are automatically saved for your next visit.
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Mini-Z Wheel Offset Calculator
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Free to start · iOS & Android
Setup App & Race Log
Got your gearing dialed? Track the whole setup.
The RC Setup App saves your settings for 600+ cars, has this gear calculator built in, and gives personalized AI tuning answers for your exact car — at the track or back in the pits.
- Gear Ratio Calculator
- AI Mechanic answers
- Setup Tracking
- Find & Share Setups
- Race Log
- Free to use
Just want the calculators?
Pit Calc Pro is our free standalone calculator app for iOS & Android.