--- title: "Fox + Son Jetmax - Reviews, Revenue and Downloads in United States | Apple App Store" description: "Precision jetting made easy — This app helps you calculate jetting for Rotax engines based on weather and altitude. Now every Rotax racer has access to the same jetting Fox + Son has used to power ou" --- # Fox + Son Jetmax — United States > Rotax jetting calculator ![Fox App Icon](https://is1-ssl.mzstatic.com/image/thumb/Purple221/v4/b4/35/7e/b4357e76-f794-a66c-f052-93c0ceca97d0/AppIcon-0-0-1x_U007emarketing-0-6-0-85-220.png/434x0w.png) **Developer:** [Trophy](https://apptail.io/developer/trophy-tpayT) **Category:** Sports **Rating:** 5.0/5 (2 ratings) **Price:** Free **Bundle ID:** net.trophyapp.foxandsonjetmax **Store:** Apple App Store **Country:** United States **Version:** 1.0.3 (released 2026-04-02) **Original Release:** 2025-09-29 **Languages:** English **App Store Link:** [Download on Apple App Store](https://apps.apple.com/us/app/app/id6748326003) **AppTail Page:** [https://apptail.io/app/fox-son-jetmax-jPSw/united-states](https://apptail.io/app/fox-son-jetmax-jPSw/united-states) ## Fox Description Precision jetting made easy — This app helps you calculate jetting for Rotax engines based on weather and altitude. Now every Rotax racer has access to the same jetting Fox + Son has used to power our engines to countless Rotax National wins and Grand Finals tickets. After many months of development and testing, we have successfully brought the same jetting algorithms we use on our dyno to a quick, easy-to-use app. We have also included all of our popular Rotax tuning tips that are found on our website, along with a handy interactive gear chart for your convenience. As we do with our website, we will continually update the app as we discover new tuning information. Anytime a new cylinder or part is introduced, all of the testing we do at the shop will flow directly to Jetmax. Jetmax will also calculate the relative horsepower for that atmospheric condition. The relative horsepower percentage is helpful information to have when selecting your gear ratio. In certain situations you can benefit from increasing your gear ratio when HP is low & decreasing your gear ratio when HP is high. Whether you're competing at the track or fine-tuning your kart for practice, Jetmax gives you accurate, reliable recommendations so you can focus on performance. Features: - Jetting calculator for Rotax engines - Calculates relative horsepower - Includes an interactive gearing chart Engineered by racers, for racers — Fox + Son Jetmax App delivers the tools you need to stay competitive on race day. *You must have a valid subscription in order to use this app. ## Fox Screenshots - [Screenshot 1](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/12/e4/1c/12e41cf2-00eb-47ee-39bc-364bfb7b28a8/Simulator_Screenshot_-_iPhone_16_Pro_-_2025-09-13_at_01.34.06.png/1284x2778.png) - [Screenshot 2](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/aa/2e/31/aa2e317d-b37c-395f-61ef-96f50801d57b/Simulator_Screenshot_-_iPhone_16_Pro_-_2025-09-13_at_01.33.59.png/1284x2778.png) ## Fox Rating Breakdown in United States - 5 stars: 2 (100%) - 4 stars: 0 (0%) - 3 stars: 0 (0%) - 2 stars: 0 (0%) - 1 stars: 0 (0%) ## Fox Reviews in United States ### ***** "It’s a must" It is the new must have if you have a Rotax at the track -- Kart Tuner, 2025-10-20 [View all Fox reviews and detailed analytics on AppTail](https://app.apptail.io/signup?utm_campaign=ai-crawl&utm_content=reviews) ## Fox In-App Purchases | Item | Price | |------|-------| | Premium Yearly | $7.99 | ## Fox Available In - [United States](https://apptail.io/app/fox-son-jetmax-jPSw/united-states) - [Australia](https://apptail.io/app/fox-son-jetmax-jPSw/australia) - [Argentina](https://apptail.io/app/fox-son-jetmax-jPSw/argentina) - [Belgium](https://apptail.io/app/fox-son-jetmax-jPSw/belgium) - [Brunei](https://apptail.io/app/fox-son-jetmax-jPSw/brunei) - [Canada](https://apptail.io/app/fox-son-jetmax-jPSw/canada) - [Switzerland](https://apptail.io/app/fox-son-jetmax-jPSw/switzerland) - [Colombia](https://apptail.io/app/fox-son-jetmax-jPSw/colombia) - [Dominican Republic](https://apptail.io/app/fox-son-jetmax-jPSw/dominican-republic) - [Estonia](https://apptail.io/app/fox-son-jetmax-jPSw/estonia) - [United Kingdom](https://apptail.io/app/fox-son-jetmax-jPSw/united-kingdom) - [Indonesia](https://apptail.io/app/fox-son-jetmax-jPSw/indonesia) - [Ireland](https://apptail.io/app/fox-son-jetmax-jPSw/ireland) - [Israel](https://apptail.io/app/fox-son-jetmax-jPSw/israel) - [Kuwait](https://apptail.io/app/fox-son-jetmax-jPSw/kuwait) - [Lebanon](https://apptail.io/app/fox-son-jetmax-jPSw/lebanon) - [Luxembourg](https://apptail.io/app/fox-son-jetmax-jPSw/luxembourg) - [Madagascar](https://apptail.io/app/fox-son-jetmax-jPSw/madagascar) - [Malta](https://apptail.io/app/fox-son-jetmax-jPSw/malta) - [Mexico](https://apptail.io/app/fox-son-jetmax-jPSw/mexico) - [Nigeria](https://apptail.io/app/fox-son-jetmax-jPSw/nigeria) - [Norway](https://apptail.io/app/fox-son-jetmax-jPSw/norway) - [New Zealand](https://apptail.io/app/fox-son-jetmax-jPSw/new-zealand) - [Portugal](https://apptail.io/app/fox-son-jetmax-jPSw/portugal) - [Romania](https://apptail.io/app/fox-son-jetmax-jPSw/romania) - [Russia](https://apptail.io/app/fox-son-jetmax-jPSw/russia) - [Slovenia](https://apptail.io/app/fox-son-jetmax-jPSw/slovenia) - [Türkiye](https://apptail.io/app/fox-son-jetmax-jPSw/turkey) - [Armenia](https://apptail.io/app/fox-son-jetmax-jPSw/armenia) - [South Africa](https://apptail.io/app/fox-son-jetmax-jPSw/south-africa) - [Angola](https://apptail.io/app/fox-son-jetmax-jPSw/angola) --- ## About AppTail [AppTail](https://apptail.io) is a mobile app intelligence platform providing app analytics, ASO (App Store Optimization) tools, keyword tracking, competitor analysis, revenue estimates, and review monitoring for iOS App Store apps. Track your app's performance, discover ranking keywords, monitor competitors, and analyze market trends. - [Search Apps](https://apptail.io) - [Top Charts](https://apptail.io/top-iphone-apps) - [Sign Up for Full Access](https://app.apptail.io/signup?utm_campaign=ai-crawl&utm_content=footer) *Data provided by [AppTail](https://apptail.io) - Mobile App Intelligence Platform*