Support

Updated September 25, 2026

Write to dudsdud@gmail.com. I reply within 3 business days. Please include your iPhone model, iOS version, app version (Profile tab, at the bottom) and what was on screen when the problem happened.

Requirements

An iPhone running iOS 17 or later. The app uses the GPS and motion sensors already in the phone. No extra hardware is needed.

The start session button stays disabled

This is the most common question, and it is not a bug. A session only starts when GPS places you inside the radius of a registered track. Away from a track the button stays off on purpose, so the app never records a stint in a parking lot.

Three ways out, in order:

Your track is not in the catalog yet: on the Drive tab, register it by marking the finish line where you are standing. That unlocks sessions at that place permanently.
You just want to see the app working: on the Drive tab, tap Simulation. The app generates laps from synthetic GPS and the full HUD runs. The session is flagged with an amber banner and never enters a league or a ranking.
You are at the track and it still will not start: check Settings › Privacy & Security › Location Services and make sure Kart Coach is set to While Using the App with Precise Location turned on. Without precise location the app cannot tell which track you are on.

Track registration refuses my marking

The app refuses to mark a finish line when GPS uncertainty is above 20 meters, because a wrong line ruins every lap time at that track. Indoors, GPS is usually worse than that. Near a window, or outdoors, it settles in a few seconds.

My lap time does not match the track's timing system

And it will not match exactly. The track's transponder crosses a loop in the ground; the app crosses a line computed from GPS, which is accurate to a few meters. The difference is usually hundredths of a second and stays constant within a session.

For race results, the transponder is always what counts. The app is there to compare you with yourself: which lap was better, where you lost time, and what changed when you changed your line.

The battery drains fast

GPS, motion sensors at 60 Hz and the screen all draw power together, and there is no way around it. Over a 15 minute stint the cost is small; over a full training day, bring a power bank. With the dashcam running, consumption goes up considerably.

The dashcam did not record

Check that the app has camera and microphone permission in Settings › Kart Coach, and that the phone had free storage. Video stays on your iPhone only: it is never uploaded to any server.

A session is missing from the list

On the Sessions tab, check the filters at the top. The No simulation filter hides simulated sessions, and the track filter hides sessions from other circuits.

Deleting sessions, account and data

One session: Sessions tab, swipe the row sideways. Video and telemetry go with it.
The whole account and everything uploaded: Profile tab. This cannot be undone.
Everything that lives only on the phone: delete the app.

You can also request deletion by email, and it is handled within 15 days. The details for each case are in the privacy policy.

Safety on track

Do not operate the phone while the kart is moving. Set up the session while stopped in the pits. Many circuits forbid devices on board: the circuit's rules outrank this app.

Suggestions and bugs

Send them to dudsdud@gmail.com. If you are on TestFlight, the fastest route is the feedback button inside TestFlight itself, since it attaches the screenshot and device details for you.