Tread Depth — Privacy Policy
Last updated: 2026-10-27
This privacy policy applies to the mobile app "Tread Depth" for Android:
- Google Play: package com.simonj.treaddepth, developer "Global Utility App Maker"
The app is developed and operated by Kyu-Hee Jang (Google Play developer name: Global Utility App Maker).
Contact: wkdrb2100@gmail.com
OVERVIEW
Tread Depth does not require an account, and we do not sell personal information. You check the tread depth of your tyres with a coin, the tyre's wear bars, a depth gauge or a photo of a coin used as a ruler, and the app compares the result with a legal line and a recommended line for the country you choose. Your vehicles and saved checks are kept in the app's storage on your device. The app also uses Google services and an advertising mediation partner for analytics, crash reporting, remote configuration, and advertising.
INFORMATION STORED ON YOUR DEVICE
For each vehicle the app keeps an optional name you type, whether it is a car or a motorcycle, and when it was added. You can keep up to 20 vehicles.
For each saved check the app keeps the vehicle it belongs to, the date and time, the country, tyre type (season) and vehicle type it was judged for, the legal and recommended lines used, and, for each tyre, your answers per groove: coin landmarks, a wear-bar answer, a gauge value, or a photo estimate with the coin used, the points you tapped and the photo file name. It also keeps your optional answers about the sidewall, the last four digits of the DOT code, an optional odometer reading, the verdicts and the app version. There is no fixed limit on the number of saved checks. An unfinished check is kept as a draft until you save or discard it.
The app may also store basic operating information such as your settings (country, units, recommended-line profile, whether the reminder is on, whether the introduction was shown), a list of saved checks used to show History quickly, cached advertising settings and a cached More Apps list. When you first open the app, the country is preset from your device's region setting; the app does not use your location for this. If saved data cannot be read, the app keeps a copy of the unreadable text in its storage so that it is not overwritten; these copies are not shown in the app and remain until you clear the app's storage.
The developer does not run a server that receives your checks. The app reads developer-controlled advertising settings and a More Apps list from Google Cloud Firestore, but it does not upload your checks, photos or vehicle names. When you open "More apps" in the menu, app icons are loaded from the web addresses in that list. When you open a source link for a legal or recommended value, it opens in your browser.
CAMERA, PHOTOS, NOTIFICATIONS AND PERMISSIONS
The photo ruler is optional. The camera permission is asked only when you tap "Allow camera" on the photo ruler screen. If you deny it, you can still pick a photo or use the coin, wear-bar or gauge methods. The camera is used for still photos, with an optional light and a 10-second timer; the app does not record video or sound. Instead of the camera you can tap "Pick photo"; the Android photo picker opens and only the picture you choose is given to the app. The app does not ask for access to all your photos.
The picture is reduced in size and saved as a JPEG in the app's cache while the check is a draft. The depth estimate is calculated on your device from the points you tap. When you save the check, the photo is copied into the app's private files and linked to that check. Photos are not included in the shared PDF report and are not uploaded by the app. The original camera capture and the copy the photo picker makes in the app's cache are not deleted by the app; they can remain there until Android clears the cache or you clear the app's storage.
The monthly reminder is off by default. When you switch it on in Settings, the app asks for notification permission (on Android versions that require it). If you deny it, the reminder stays off. When it is on, the app schedules one local notification on your device 30 days after your last saved check; no server sends it.
The app does not request microphone, location, contacts, Bluetooth or health data permissions. It uses internet access and the Android advertising ID permission for the services below.
ANALYTICS, CRASH REPORTING, AND ADS
Google Firebase Analytics may process limited app-usage and technical information, such as app launches and screen views; tab changes; starting a check (method, tyre type, vehicle type, whether the spare is included and the kind of legal line); groove answers (method and answer type) and skipped steps; results shown and checks saved (verdict, a range for the number of measured tyres, the number of unknown tyres, the number of photos, and whether an odometer reading was entered); failed saves, deleted checks, draft found, resumed or discarded, and abandoned checks; photo ruler steps (captured, used or abandoned, and a count of warnings); camera and notification permission results; setting changes and their values (the country you choose, units, recommended-line profile, reminder on or off, and measuring method); vehicles added, edited, deleted or selected (car or motorcycle); report shares and their result; guide and source-link opens; reminder planning results; storage repairs and unreadable-data counts; the introduction being completed; menu actions such as review and More Apps taps and review results; ad revenue events (ad format, value, currency and precision); app version, device type, and app-instance identifiers. These events do not include depth values, vehicle names, DOT codes, odometer readings or photos.
Google Firebase Crashlytics may process crash reports and related technical information needed to diagnose app problems.
The app shows ads through Google AdMob. A banner may appear at the bottom of the Check, Guide and History tabs. Full-screen ads may appear when the app opens or returns to the foreground, and occasionally after you save a check (not after the first save each time the app is started). When you press Back to leave the app, the exit dialog may show an ad. The app does not start a full-screen ad while you are setting up a check, answering its steps, using the photo ruler or viewing its unsaved result. AdMob may also request ads from the InMobi mediation network. Google and InMobi may process advertising identifiers and device, app, consent, network, and ad-performance information to provide and measure ads, and may use an IP address to estimate an approximate location even though the app has no location permission.
ADVERTISING CHOICES
When the app launches, it first checks Google's consent message (UMP). The Google Mobile Ads SDK is started, and the advertising settings are read, only when that check allows ad requests. Where consent is required (for example in the EEA and UK), personalized ads are requested only if your choices allow them; otherwise ads are non-personalized. Where Google reports that consent is not required, ads may be personalized. If the consent result does not allow ad requests, or the consent check has not completed, the app does not request ads. If the consent message cannot be loaded, the app still requests non-personalized ads, and "Privacy choices" is not shown until the app is started again. Where Google requires it, the menu shows "Privacy choices", which reopens the consent message so you can change your advertising choice; if an error occurs while that message is open, the app does not request new ads until it is started again. The app works whatever you choose.
STORAGE AND YOUR CONTROL
On the Check tab you can discard an unfinished check with "Discard". To delete a saved check, open it and tap the delete icon, then confirm; the check and its saved photos are deleted from the app. In Settings, under Vehicles, you can delete a vehicle (except the last one) after a confirmation; this deletes its saved checks, their photos and its unfinished check. A check that cannot be read is listed in History and can be deleted from its screen in the same way. When the app starts, it deletes files in its own photo folders that no saved or unfinished check uses (this does not include the camera and photo picker copies described above). Switching the reminder off cancels the scheduled notification. You can also clear the app's data in Android settings or uninstall the app.
The app turns off Android app-data backup, so your vehicles, checks and photos are not included in Google's backup of app data.
"Share report (PDF)" creates a one-page PDF in the app's cache and sends it through the system share sheet to a destination you choose. The report contains the vehicle name, the date, the verdicts, the depth for each tyre, notes (such as the DOT week and year and sidewall warnings), the lines used with their sources, and the guidance notice. When the app starts, it deletes these PDF files once they are more than 24 hours old; files whose age it cannot check may be kept. The app does not delete copies you shared elsewhere.
Because we do not receive your checks, we cannot delete them for you; the controls above remove them from the app. For questions about data processed by Google or InMobi, or to ask us for help with a privacy request, contact us at the address below.
Data processed by third parties is retained according to their service settings and policies. We use these services under their applicable terms, and we ensure that third-party service providers with whom we share user data provide the same or equal protection of that data as stated in this policy.
- Google Privacy Policy: https://policies.google.com/privacy
- Firebase privacy information: https://firebase.google.com/support/privacy
- Google advertising technologies: https://policies.google.com/technologies/ads
- InMobi Privacy Policy: https://www.inmobi.com/privacy-policy
SECURITY
Your vehicles, checks, photos and cache files are kept in the app's private storage on your device, which the operating system protects from other apps; they are not separately encrypted by the app, so protect your device with a screen lock. A PDF report you share can be read by anyone who receives it. Apart from the limited analytics events described above, the app does not upload your saved data. Communication between the app and Google services and the ad mediation partner uses encrypted connections (HTTPS/TLS). No method of storage or transmission is completely secure, but we limit what the app collects to what is described in this policy.
IMPORTANT NOTICE
Tread Depth gives guidance only. It does not replace a tread depth gauge or an inspection by a tyre specialist or mechanic, and a "Good" result does not mean a tyre is safe. Coin and wear-bar results are approximate, and photo results are estimates that can be wrong if the coin tilts or does not reach the bottom of the groove. Legal and recommended values come from the sources shown in the app and can change; check the current rules where you drive. If you see damage, uneven wear or a low reading, have the tyre checked by a professional. Measure only when the vehicle is parked safely with the engine off.
CHILDREN
The app is intended for users aged 18 and over and is not directed to children. We do not knowingly collect personal information from children.
CHANGES
We may update this policy if the app or its services change. The date above shows the latest revision.
CONTACT
Kyu-Hee Jang (Google Play developer: Global Utility App Maker)
Email: wkdrb2100@gmail.com