Tire Calculator (Offset&Speed)

Offset & speed error calc.

$1.99 · Designed for iPad. Not verified for macOS.

Easily calculate the effects of wheel and tire upgrades. Quickly check inner and outer rim position changes, tread changes, and speedometer error from tire size changes. Easily calculate the effects of wheel and tire size changes A convenient calculation tool for anyone considering wheel upgrades, tire size changes, or fitment adjustments. Simply enter your current and new specifications to quickly compare the impact on your vehicle. -Main Features -Wheel Comparison •Calculate inner rim position changes •Calculate outer rim position changes •Calculate tread width changes -Tire Comparison •Calculate speedometer error (%) •Compare indicated speed and actual speed •Vehicle-specific speedometer error can also be included in calculations -Speedometer Error Measurement •Accurate GPS-based speed measurement -Data Storage •Save comparison records -Important Notes Measurement results may vary depending on GPS reception and environmental conditions. Use measured values as a reference only. Actual wheel and tire dimensions may vary by manufacturer and model. Calculation results are for reference purposes only. Always consult a qualified professional before making vehicle modifications. The developer assumes no responsibility for any damages or issues resulting from the use of this application. -Specifications Wheel Offset Calculator •Rim Width (in): 3" to 16" (supports 0.25" increments) •Offset (mm): -60 to +70 •Backspacing (in): 3" to 13" Speedometer Error Calculator •Tire Width (mm): 125 to 405 •Aspect Ratio (%): 20 to 90, including 82 (R) •Supports 82-series radial tires commonly used on vans and light trucks •Rim Diameter (in): 10 to 32 •Direct Tire Diameter Input: 100 to 1500 mm or 4 to 60 in •Vehicle Speedometer Error Correction (%): -20 to +20 Speedometer Error Measurement •Measurable speed range: 10 to 200 km/h or 10 to 200 mph

Ratings & Reviews

  • 5.0
    out of 5
    4 Ratings

Updated the app design Bug fixes and performance improvements

Version 5.0.0

The developer, Satoshi Mori, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    • Satoshi Mori
    Size
    • 9.9 MB
    Category
    • Utilities
    Compatibility
    Requires iOS 26.0 or later.
    • iPhone
      Requires iOS 26.0 or later.
    • iPad
      Requires iPadOS 26.0 or later.
    • Mac
      Requires macOS 26.0 or later and a Mac with Apple M1 chip or later.
    Languages
    • English and Japanese
    Age Rating
    4+
    Copyright
    • © 2017 toshi
  • Privacy Policy

    • Supports

    • Family Sharing

      Up to six family members can use this app with Family Sharing enabled.

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