Tire Size Calculator

Compare tire and wheel specs conveniently and get recommendations for tire and wheel upgrades. Support both Imperial and Metric units.
What makes this app standing out from the crowd: calculate approximate equivalent sprung (chassis) weight difference after changing to a new set of tire+wheel.
http://www.tirerack.com/wheels/tech/techpage.jsp?techid=108

Experienced car mod drivers know that a light weight tire+wheel package with good quality is always a great mod investment to have. This app helps to quantify the performance improvement that can be achieved by such investment: the equivalent sprung weight deduction with a set of 4 lightweight new tires and rims.

This app helps you to choose upgrade tire and wheel safely and wisely, because Safety and Performance both matter!

This is an universal app that works great and responsively on both iPhone/iPod Touch and iPad.
NO need to pay twice for the same app!

Tire Size Calculator is an app that gives you concise info and intuitive interactive ways to help you:

1. Get recommended upgrade/replacement tire sizes, with adjustable difference variables (rim size diff./section width diff./circumference diff.) between new tire and old tire.

2. Calculate tire sizes, and compare tires with detailed specs, in either Imperial or Metric units. See the visual differences between tires using the scaled tire graph with two display modes: side-by-side as two complete tire circles, or use half of each tire to constitute one tire circle.

3. Calculate approximate equivalent car chassis (sprung) weight differences after change to the replacement/upgrade tire+wheel, using the following data: car weight, engine max torque, car 0-60 mph/0-96.6 km/h time, tire/wheel sizes/weights, in either Imperial or Metric units.

Detailed description:

1. Get recommended upgrade/replacement tire sizes, with the following adjustable difference variables between new tire and old tire:

• Rim diameter difference (-3" ~ +3")
• Section width difference (-30 mm ~ +30mm)
• Tolerable tire circumference difference (-3% ~ +3%)

You can conveniently choose one of the recommended tires to compare to the old tire by selecting the tire from the list.

2. Calculate tire sizes, and compare tires with the following specs, in either Imperial or Metric units:

• Section Width (145 mm ~ 395 mm)
• Aspect Ratio (20 ~ 85)
• Rim Diameter (10" ~ 30")
• Load Index (60 ~125)
• Speed Rating (L ~ Y)
• Suitable Rim Widths
• Section Height
• Tire Overall Diameter
• Tire Circumference
• Actual Speed when speedometer reads 60
• Actual Speed when speedometer reads 100
• Scaled visual graphs of the old tire and new tire

You can use the scaled tire graph to see the visual differences in tire section height (sidewall height), tire diameter, rim diameter, and circumferences, in the two modes:

• Side by Side: two tires displayed as two whole circles next to each other, great for seeing overall visual appearance differences.
• Half Circles: old tire as the left half, new tire as the right half, combined to form one circle, great for seeing differences in tire section height, tire diameter, and rim diameter.

Tap the tire graph to toggle between the two modes.

3. Calculate approximate equivalent car chassis (sprung) weight differences after change to the replacement/upgrade tire+wheel, in either Imperial or Metric units, using the following data:

• Car Weight (with old tire+wheel)
• Engine Max Torque
• Car 0-60 mph/0-96.6 km/h time (with old tire+wheel)
• Old Tire/Wheel Sizes
• New Tire/Wheel Sizes
• Old Tire/Wheel Weights
• New Tire/Wheel weights

Colors of the specs table cells indicate the compatibility of the new tire in that spec:

• No color: compatible
• Green: improved
• Yellow: tolerable
• Red: not compatible