Compare setups side by side and find the ideal pinion/spur combination.
% 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.
Free RC tools to dial in your car between rounds.
RC Speed Calculator
Motor KV, battery voltage, gearing, and tire size → top speed of any electric RC car.
RC Gear Ratio Chart Maker
Build a printable pinion/spur chart for any class — gear ratio (FDR) or rollout (mm). 1/10, 1/12 pan, 1/8 presets included.
RC Corner Weight Calculator
Enter per-wheel weights to compute cross weight and balance — critical for oval and on-road tuning.
RC Shock Oil Weight Converter
Convert wt ↔ cSt ↔ Mugen / Yokomo numbers, plus starting-point oil weights by class.
RC Battery Runtime Calculator
How long will your LiPo last? Estimate runtime by class and driving style.
RC Pill Insert Calculator
Diff insert geometry for 1/8 buggies — match your gear-diff pill setup to your conditions.
Mini-Z Wheel Offset Calculator
Fitting an AutoScale body to a Kyosho Mini-Z? Get the exact wheel offset for any width, plus a wheelbase & motor-mount reference.
Free to start · iOS & Android
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.

