Tire Calculator (Offset&Speed)5.1.0 - App Store

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

Version History Added tire diameter display to the main screen of TireCalculator. 5.1.0 Jul 2 Updated the app design
Bug fixes and performance improvements 5.0.0 Jun 9 Minor bug fixes 3.3.2 01/28/2025 Minor bug fixes and specification changes 3.3.1 02/25/2024 Thank you for downloading.
This version has the following fixes:
・Change of design
・Minor bug fixes 3.3.0 04/09/2023 Fixed minor bugs 3.2.2 05/01/2022 -Fixed minor bugs 3.2.1 09/29/2021 -Supported iOS 15
-Fixed minor bugs 3.2 09/24/2021 Minor bug fixes 3.1.1 07/04/2021 Thank you for downloading and using it.

Ver 3.1.0
- By request, we also support 0.25 units of rim width for wheel calculation (selectable from the setting screen).
- The date and time when the data was saved is displayed in the list.
- Other minor bug fixes and specification changes have been made. 3.1.0 03/07/2021 Thank you for downloading
・ Improved visibility
・ Minor adjustment 3.0.1 11/05/2020 Thank you for downloading.
Update content
・ Improved visibility and operability
・ Addition of save function
・ Minor bug fixes 3.0.0 11/01/2020 Correspond to radial tire (Aspect ratio 82%) for vans and light trucks by user's request.
Select and use the tire error calculation aspect ratio "R".
At the same time, we are also making minor bug fixes
Thank you in advance for TireCalculator. 2.2.0 05/07/2019 Thank you for using
Expanded the range of tire width (135,145) 2.1.0 03/29/2019 Thank you for your download!
For the comfortable use, we updated the following.

[Ver 2.0.0 update content]
· We also made it possible to calculate backspace wheels
· Compatible with iPhone Xs, XsMax, XR and others
· Automatic calculation function (calculate in real time without pressing calculation button)
· Some UI and design changes to improve convenience
· Other minor defect correction and specification change 2.0.0 12/28/2018 Thank you for your download
I made a minor bug fix 1.4.1 05/22/2018 Thank you for downloading.
This update added the function to run the vehicle and measure the error of the speedometer from GPS position information!
Other, we made minor adjustments. 1.4.0 05/16/2018 · Supports iPhone 4s and iOS 9
· Expansion of tire and wheel selection values
· Minor adjustment 1.3.1 10/15/2017 Corresponds to inch mile display
Compatible with iPhoneX
Compatible with iOS 11
Increase input width
Minor bug fixes 1.3.0 10/09/2017 ・Fixed minor bugs
・Improve affinity with iPad
・Design change for improved visibility and operability 1.2.0 07/13/2017 1.1.0 03/05/2017 1.0 02/14/2017