ThirdGear

Built for car enthusiasts who enjoy spending time in third gear.

Mix and match engines, gearboxes, final drives and tires, then see what each combination does to speed and rpm in every gear.

Change a ratio and everything redraws: the rpm-vs-speed trace, tractive effort against the traction limit, where each gear tops out, and where you should be shifting.

Features

A/B comparison: Put two setups side by side on the same charts. Swap a diff, a gearbox, or a whole engine and watch what moves.

Acceleration and traction - Timed runs with your shift times factored in, plus tractive effort per gear against the grip you actually have.

Optimal shift points - Where the next gear starts pulling harder than the one you're in, not just where the limiter is.

Lap telemetry gear map - Import a lap from RaceChrono and see which gear you're in at every point on the track, with shift logic you can tune to match how you actually drive it.

Garage - Save setups, load them back, and share one with a mate as a QR code.

Everything runs on your device for free. No account, no sign-in, no network, and nothing leaves your phone.