It’s a must
It is the new must have if you have a Rotax at the track
Free
In-App Purchases
About
This application simplifies jetting calculations for Rotax engines, factoring in weather and altitude. It provides racers with precise tuning recommendations, including relative horsepower and an interactive gear chart, to optimize performance on race day.
✓Rotax engine jetting calculator
✓Weather and altitude adjustments
✓Relative horsepower calculation
✓Interactive gear chart
✓Rotax tuning tips
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What's New in Fox + Son Jetmax
1.0.3
April 2, 2026
-Added "US Spec Micro" engine type -Optimized jetting for longer tracks
Subscription plans
Premium Yearly
Access to the app for the year
$7.991 Year
7 Days trialUser reviews
FAQ
What is Fox + Son Jetmax?
Fox + Son Jetmax is a mobile application designed to calculate precise jetting for Rotax engines. It uses weather and altitude data to provide optimal tuning recommendations for racers.
How does Fox + Son Jetmax help with performance?
Jetmax calculates relative horsepower, which is crucial for selecting the correct gear ratio. It also provides accurate jetting recommendations to ensure your engine runs at its best.
Is Fox + Son Jetmax free to use?
No, Fox + Son Jetmax requires a valid subscription to use. The Premium Yearly plan is available for $7.99 per year and includes a 7-day free trial.
What devices does Fox + Son Jetmax support?
Fox + Son Jetmax is currently supported on iPhone and iPod devices.
How often is Fox + Son Jetmax updated?
The app is updated regularly to incorporate new tuning information and testing results from new cylinders or parts. The latest version is 1.0.3, last updated on April 2, 2026.
Does Fox + Son Jetmax have ads?
No, Fox + Son Jetmax is ad-free. The application is designed to provide an uninterrupted user experience for racers.
What is the age rating for Fox + Son Jetmax?
Fox + Son Jetmax has an age rating of 4+, making it suitable for a wide range of users.
Can I cancel my Fox + Son Jetmax subscription?
Yes, users can typically cancel their subscription through their device's app store settings. The app offers a 7-day free trial for the Premium Yearly plan, allowing users to test it before committing.
