# Fox + Son Jetmax vs KartCoach

The clearest difference is update cadence: KartCoach at weekly against Fox + Son Jetmax's every 3 months. Fox + Son Jetmax's advantage is iOS requirement (15.1 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Fox + Son Jetmax sells 1 in-app purchase, starting at $7.99 per year and KartCoach sells 2 in-app purchases, starting at $0.99 per month. Whichever you choose, the download price is not the number that matters.

Fox + Son Jetmax ships an update every 3 months, KartCoach weekly. The most recent releases landed on September 23, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Fox + Son Jetmax | KartCoach |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/fox-plus-son-jetmax/id6748326003/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Weekly** |
| Monetization | Subscription | — |
| Size | 16 MB | 20 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Trophy Inc.](https://appshunter.io/developer/1752591571) | [Foundation 51 Holdings, LLC](https://appshunter.io/developer/1896689635) |

## What reviewers say

### Fox + Son Jetmax

[App page](https://appshunter.io/ios/app/fox-plus-son-jetmax/id6748326003)

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.

**Highlights:** Rotax engine jetting calculator, Weather and altitude adjustments, Relative horsepower calculation, Interactive gear chart, Rotax tuning tips

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Yearly | $7.99 | per year |


### KartCoach

[App page](https://appshunter.io/ios/app/kartcoach/id6769803627)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| KartCoach Pro (Monthly) | $0.99 | per month |
| KartCoach Pro (Yearly) | $4.99 | per year |


## Frequently asked questions

### Is Fox + Son Jetmax free?

Fox + Son Jetmax is free to download, with in-app purchases available.

### Is KartCoach free?

KartCoach is free to download, with in-app purchases available.

### Do Fox + Son Jetmax or KartCoach have ads?

Neither Fox + Son Jetmax nor KartCoach shows ads.

### Which is updated more often, Fox + Son Jetmax or KartCoach?

Fox + Son Jetmax ships an update every 3 months, and KartCoach weekly. Most recently, Fox + Son Jetmax was updated on September 23, 2026 and KartCoach on October 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*