GTrace - G-Meter & Logger

One-time purchase. No subscription, no in-app purchases.

WHILE YOU DRIVE

- Live G-G diagram, lateral and longitudinal G shown together

- Trailing trace, with peak lateral and longitudinal G held on screen

- Jerk shown as a crosshair, so you can see how smoothly you transfer load

- Speed readout, switchable between km/h and mph

- Audible alert when you exceed your chosen G threshold

- Comfort and Sport modes with separate display ranges for street and track

- Three display layouts: standard, info + speed, and video preview

- Phone holder mode, so a vertically mounted phone still reads longitudinal G correctly

MEASUREMENT

- Gravity component removed to isolate true vehicle acceleration

- 2nd-order Butterworth IIR low-pass filter with adjustable cutoff frequency

- Configurable sampling rate

- Axis inversion, so mounting orientation doesn't matter

AFTER THE RUN

- G-G heat map showing which part of the friction circle you actually used, so you can see the balance between cornering, braking and acceleration at a glance

- Synced playback: G-G + map, G-G + video, G-G + acceleration graph, or map + graph, at adjustable playback speed

- Time-series graphs for longitudinal G, lateral G, longitudinal jerk, lateral jerk and speed

- GPS trace drawn on a map, with top and average speed

RECORD AND SHARE

- Voice recording, synced to the acceleration data for commentary and notes

- Video recording with audio, played back with the G-G trace overlaid

- Shareable video export: overlay G-force traces and readings on recorded footage. Export the whole clip or a selected range.

- Select video recording resolution: 480p, 720p or 1080p

- CSV export for spreadsheets or your own analysis tools

- Native binary format (.ggx) import and export, for backups and moving data between devices

WHO IT'S FOR

- Track day, sports driving and time attack enthusiasts

- Drivers working on their technique on mountain roads

- Anyone chasing smoother, more passenger-friendly load transfer

- Motorsport competitors who want their practice data kept

- Anyone who wants their car's behaviour in numbers

English and Japanese. iPhone only, iOS 15.6 or later.

Note: measurements use the iPhone's built-in accelerometer and gyroscope. Mount the phone firmly in the vehicle for accurate readings.

Note: GPS trace and speed recording require location permission.

Note: this app does not include lap timing.