# Gear Speed and Tire Size

> App for comparing tire sizes to transmission gears and differential ratios. (iPhone/iPad app by Scott Galaba.)

- Source: https://appshunter.io/ios/app/gear-speed-and-tire-size/id1048868556 (this page in markdown: same URL + `.md`)
- Developer: [Scott Galaba](https://appshunter.io/developer/1048868555)
- Category: Productivity, Sports
- Price: $0.99 (on sale, was $1.99)
- Age rating: 4+
- Requires: iOS 17.6 · 4 MB
- Languages: American English
- Released: 2015-10-26
- Data updated: 2026-08-24
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/gear-speed-and-tire-size/id1048868556/reviews.md

## What is Gear Speed and Tire Size?

The Gear Speed and Tire Size Calculator app is for comparing different tire and wheel combinations to transmission gears and differential ratios. Preload gear ratios are provide and gear speeds 4-8 are selectable to tailor the output results to the transmission (4-speed, 5-speed, 6-speed, 7-speed, 8-speed).

The Gear Speed Graph is interactive and allows one to compare results when hovering over / selecting a line graph point(s) to display the Comparison Graph Results Panel. The Gear Speed Graph also allows one to compare, hide, or show a given gear speed line graph by selecting the corresponding legend indicator to toggle the display of the selected line graph.

Calculations can be printed or saved into a PDF by selecting Share PDF Results. 

Multitasking / Slide Over / Split View support is included for the latest iPads. 

This App includes three (3) different calculators:

(1) Gear Speed Calculator - For calculating the speed in MPH or KPH for a given tire size, up to eight (8-speed) transmission gear ratios and differential ratio combination. The results appear in both an interactive Gear Speed Graph and Gear Speed Results Table (table not available for 3.5 inch display but does appear in the Share PDF Results feature). RPM Data Points are adjustable, allowing for further tailoring of the Gear Speed Graph and Results, to very specific RPM ranges, or to expanded the ranges beyond 9000 rpm. 

(2) Tire Size Calculator - For comparing the original equipment tire size (Rim in inches) to alternate after market tire sizes.

(3) TMX Tire Size Calculator - For comparing the original equipment tire size (Rim in millimeters) to alternate after market tire sizes.

## Key features

- Gear speed and tire size comparison
- Interactive gear speed graph
- Printable/savable PDF results
- Multitasking support for iPads
- Three distinct calculators
- Adjustable RPM data points

## Chart rankings

- #184 in Top Paid · Productivity (US App Store)

## Recent user reviews (3 of 3)

All indexed reviews: https://appshunter.io/ios/app/gear-speed-and-tire-size/id1048868556/reviews.md

### 3/5 — Good idea, sharing is iffy

*2016-09-10*

The overall concept is great.  
However, when trying to share a PDF of the results it is slow to update the data.  It often uses the previous data for several shares before finally picking up the newly input data to populate the sheet with.  This is aggravating to say the least when trying to compare tire sizes and performance.

**Developer response:** Thank you for your review and recommendation!
As of release 3.6.1 the social sharing function along with the base code was updated. 
The responsiveness of both the app and sharing results via PDF have been improved.

### 3/5 — :/

*2016-08-30*

Redline only goes to 8k, needed it to rev to 9-10k...feels like I just wasted a dollar...

**Developer response:** Thank you for your review and recommendation!
As of release 3.5.2 the redline limitation has been removed; an RPM Preferences tab has been added. 
RPM Preferences - RPM Data Points are now adjustable, allowing for further tailoring of the Gear Speed Graph and Results, to very specific RPM ranges, or to expanded the ranges beyond 9000 rpm.

### 5/5 — RPM to MPH/KPH

*2016-05-07*

Very nice app that converts engine rpm to vehicle speed by taking into consideration transmission gear ratio, final drive ratio, and tire size.  Results are presented in a table, a comprehensive graph and printed document.   My Dodge Charger has an 8 speed AT that can be switched into a paddle shifted MT and this app handles all 8 ratios.   In addition when I change between the Dodge approved 20 inch summer and the 18 inch winter tires, this app calculates any resulting vehicle speed differences.   You can also input the new gear ratio if you're one who changes out the rear axle gearing for street vs. track.  Author is responsive to suggestions and continually seeks ways to improve the app.  Well done.

**Developer response:** Thank you for your review of the Gear Speed and Tire Size app!

## Frequently asked questions about Gear Speed and Tire Size

### What is Gear Speed and Tire Size used for?

Gear Speed and Tire Size is used to compare different tire and wheel combinations to transmission gears and differential ratios. It helps users calculate gear speeds for various configurations and analyze their impact on vehicle performance.

### Does Gear Speed and Tire Size have ads?

No, Gear Speed and Tire Size is ad-free. Users can enjoy the full functionality without any advertisements interrupting their experience.

### How much does Gear Speed and Tire Size cost?

Gear Speed and Tire Size is a paid application, available for a one-time purchase of $0.99.

### What devices is Gear Speed and Tire Size compatible with?

Gear Speed and Tire Size is compatible with both iPhone and iPad devices, supporting multitasking features on the latest iPads.

### How often is Gear Speed and Tire Size updated?

The app was last updated on December 13, 2025, indicating ongoing support and potential for future improvements and bug fixes.

### Can I export my calculations from Gear Speed and Tire Size?

Yes, you can print or save your calculations into a PDF by selecting the 'Share PDF Results' option within the app.

### What age rating does Gear Speed and Tire Size have?

Gear Speed and Tire Size has an age rating of 4+, making it suitable for a wide range of users.

### What are the different calculators included in Gear Speed and Tire Size?

The app includes three calculators: a Gear Speed Calculator for calculating speed based on tire size and gear ratios, a Tire Size Calculator for comparing original equipment tire sizes in inches, and a TMX Tire Size Calculator for comparing sizes in millimeters.

## Version history (last 5 releases)

### 4.1.7 — 2026-08-11

Minor code update

### 4.1.2 — 2025-12-13

Minor code update

### 4.1.1 — 2025-09-23

Update to support for iOS 26, iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, iPhone Air, iPhone 16e, iPad, iPad Air 11-inch, iPad Air 13-inch, iPad Pro 11-inch, iPad Pro 13-inch, iPad mini, and as a (Designed for iPad) app for Apple Silicon (arm64) Mac’s including the latest MacBook Air, MacBook Pro, iMac, Mac mini, Mac Studio, Mac Pro and Apple Vision Pro.

### 4.0.8 — 2025-03-24

Minor code update.

### 4.0.7 — 2025-02-10

Minor code update

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## More apps by Scott Galaba

- [Bitcoin Satoshi Calculator](https://appshunter.io/ios/app/bitcoin-satoshi-calculator/id6740068349)

All apps by Scott Galaba: https://appshunter.io/developer/1048868555

## Related topics

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-24.*