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.
Good idea, sharing is iffy
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.
United States:/
Redline only goes to 8k, needed it to rev to 9-10k...feels like I just wasted a dollar...
United StatesRPM to MPH/KPH
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.
United States
Updated to support for iOS 17, iPhone 15, iPhone 15 plus, iPhone 15 Pro, iPhone 15 Pro Max, iPhone SE, iPad, iPad Air, iPad Pro (11-inch), iPad Pro (12.9-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.
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