Gear Calculator Plus vs SDG Rotor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Gear Calculator Plus
Calculate a car's theoretical speed in any gear based on engine RPM, transmission, differential ratios, and tire size. It can also determine travel distance per engine revolution and estimate top speed for each gear. Supports both metric and imperial units.
- Calculate theoretical speed per gear
- Calculate travel distance per engine revolution
- Determine top speed for each gear
- Metric or Imperial units
- Universal app for iPhone and iPad
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Gear Ratio Speed Calculator. With the gear ratios of the transmission and differential, and the size of the tires, it becomes possible to calculate the speed of the car for a particular gear at a particular engine RPM. Features: Calculate theoretical speed for a car for each of its gear ratios. Calculate travel distance for each engine revolution. Use maximum RPM to figure top speed for each gear. Metric or Imperial units for selection. Universal app for both iPhone and iPad. Axle ratio are similar as Final Drive Ratio. If a car has less than 6 gears, only enter the ratios that apply. Note that you will get unreal speeds for overdrive gears. This is because in reality top speed is physically limited by it power or by aerodynamic drag. Thanks for your support and do visit nitrio.com for more apps for your iOS devices.
SDG Rotor
This tool helps high-performance vehicle owners ensure the safety of their supercharger rotor RPM. It allows users to input supercharger details and engine RPM for instant safety checks, leveraging expert knowledge in performance vehicles.
- Supercharger rotor RPM safety checks
- Input supercharger details and engine RPM
- Instant safety assessments
- Expertise in high-performance vehicles
- User-friendly design
- Supports global units and standards
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SDG Motorsports Presents: The Ultimate IHI Supercharger Tool Brought to you by SDG Motorsports, this app is the essential companion for Hellcat, Redeye, Trackhawk, Hellephant, and Demon enthusiasts. Guarantee the safety of your supercharger rotor RPM with our precision tool designed for the high-performance vehicle owner. With SDG Motorsports, you get more than just an app; you get a partner in performance and safety. Why SDG Motorsports? • Expertise in Performance: Leveraging SDG Motorsports deep understanding of high-performance vehicles, our app provides unparalleled accuracy in supercharger safety assessments. • User-Friendly Design: Developed by the experts at SDG Motorsports, this app allows you to easily input your supercharger details and engine RPM, offering safety checks in an instant. • Global Standards: No matter where you tune from, SDG Motorsports ensures that our app supports a broad spectrum of units and standards for worldwide accessibility. Your Safety, Our Priority With SDG Motorsports, stay confident in your vehicle’s performance and safety. Download today to ensure your supercharger setup is not just powerful, but also safe. Disclaimer: While SDG Motorsports strives to provide accurate and up-to-date information through our Supercharger Safety Tool, the nature of high-performance vehicles and the variability of modifications mean outcomes can vary widely. As such, SDG Motorsports cannot be held responsible for any damage, loss, or injury resulting from the use of this app. Users are encouraged to proceed with caution and consult with professional tuners or technicians when making significant modifications to their vehicles. This app is intended as a guide only, and reliance on its output is at the user's own risk.
Screenshots
Verdict
The clearest difference is review sentiment: SDG Rotor at 100% against Gear Calculator Plus's 0%. SDG Rotor also leads on price (Free vs $2.99) and rating (5.0 vs 3.6). Gear Calculator Plus's advantage is ratings volume (5 vs 1) and iOS requirement (13 vs 15.6). On ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
SDG Rotor is free to download; Gear Calculator Plus costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
SDG Rotor holds the better App Store score, 5.0 against 3.6. That said, the two scores are not equally well evidenced: Gear Calculator Plus has 5 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 0% of Gear Calculator Plus's written reviews are positive against 100% of SDG Rotor's.
Gear Calculator Plus ships an update every 29 months, SDG Rotor every 2 days. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.
| Parameter | Gear Calculator Plus | SDG Rotor |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 3.6 (5 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 0.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 5 — better | 1 |
| Update frequency | Every 29 months | Every 2 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13 — better | 15.6 |
| Further details — not scored | ||
| Size | 1 MB | 46 MB |
| Age rating | 4+ | +17 |
| Developer | Nitrio | Stephan Monette |
Customer experience
Gear Calculator Plus
SDG Rotor
In-app purchases
Gear Calculator Plus
No in-app purchases
SDG Rotor
No in-app purchases
Questions
Is Gear Calculator Plus free?
Is SDG Rotor free?
Which has better reviews, Gear Calculator Plus or SDG Rotor?
Do Gear Calculator Plus or SDG Rotor have ads?
Which is updated more often, Gear Calculator Plus or SDG Rotor?
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