Tire Size Calculator Program
Copyright© Scott Galaba 1998-2008
Version 2.4
by Scott Galaba
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This program is for comparing original equipment tire size to alternate after market tire sizes. All calculations are round up. Calculations are to be treated as approximate only, due to variations in how tires are manufactured.
To use this program you need to key in seven (7) pieces of information. The tire tread width, sidewall ratio, and wheel rim diameter from each of the two tires to be compared and a speedometer reading to be used to compute the effect the after market tire size has on your speedometer.
The following is an example to help to decode a tire size like 185/65R14
185 = tire width in millimeters, measured from sidewall to sidewall
65 = sidewall ratio, the ratio of sidewall height to tire width
14 = wheel rim diameter in inches
After keying in the seven (7) pieces of information, click on the "Compare Tires" button below to have the two tire sizes compared.
This program is setup to compare either U.S. (English) tires or Metric (TRX) tires.
Please select from one of the two choices below:
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Step 1: Key in the following information from the tires being compared.
| Original Equipment Tire | Alternate After Market Tire | ||
|---|---|---|---|
| Tire Width in (mm): | Tire Width in (mm): | ||
|
| Aspect Ratio: | ||
| Rim Diameter in (inch): | Rim Diameter in (inch): | ||
| Speedometer Reading: | |||
Step 2: To compare the above tires, please click on the "Compare Tires" button below.
Step 3: To see the results of the comparison goto the following: U.S. (English) Tires Comparison Information Section
When you are done comparing, check out the Gear Speed Calculator Program.
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U.S. (English) Tires Comparison Information Section
| Original Equipment Tire | Alternate After Market Tire | ||
|---|---|---|---|
| Side Wall Height (inch): | Side Wall Height (inch): | ||
| Tire Width (inch): | Tire Width (inch): | ||
| Tire Diameter (inch): | Tire Diameter (inch): |
| |
| Tire+Wheel Radius (inch): | Tire+Wheel Radius (inch): |
| |
| Tire Circumference (inch): | Tire Circumference (inch): |
| |
| % Difference: |
| ||
| Revolutions per mile: | Revolutions per mile: |
| |
| Revolutions per kilometer: | Revolutions per kilometer: |
| |
| Speedometer Reading: | New Speedometer Reading: |
| |
NOTE: New Speedometer Reading = What speed the car will need to go (with the after market tires on) to be traveling at the same speed if the car had the orginal tires on.
To compare additional tires, go back to the "Tires to be Compared Section" and type over the information you want to change. After making the changes, click on the "Compare Tires" button to recalculate.
To reset this form, click on "Clear Form" button below.
Step 1: Key in the following information from the tires being compared.
| Original Equipment Tire | Alternate After Market Tire | ||
|---|---|---|---|
| Tire Width in (mm): | Tire Width in (mm): | ||
|
| Aspect Ratio: | ||
| Rim Diameter in (mm): | Rim Diameter in (mm): | ||
| Speedometer Reading: | |||
Step 2: To compare the above tires, please click on the "Compare Tires" button below.
Step 3: To see the results of the comparison goto the following:
Metric (TRX) Tires Comparison Information Section
Metric (TRX) Tire Comparison Information Section
| Original Equipment Tire | Alternate After Market Tire | ||
|---|---|---|---|
| Side Wall Height (mm): | Side Wall Height (mm): | ||
| Tire Width (mm): | Tire Width (mm): | ||
| Tire Diameter (mm): | Tire Diameter (mm): | ||
| Tire+Wheel Radius (mm): | Tire+Wheel Radius (mm): |
| |
| Tire Circumference (mm): | Tire Circumference (mm): |
| |
| % Difference: |
| ||
| Revolutions per mile: | Revolutions per mile: |
| |
| Revolutions per kilometer: | Revolutions per kilometer: |
| |
| Speedometer Reading: | New Speedometer Reading: |
| |
NOTE: New Speedometer Reading = What speed the car will need to go (with the after market tires on) to be traveling at the same speed if the car had the orginal tires on.
To compare additional tires, go back to the "Tires to be Compared Section" and type over the information you want to change. After making the changes, click on the "Compare Tires" button to recalculate.
To reset this form, click on "Clear Form" button below.
Copyright© Scott Galaba 1998-2008
Tire Size Program, Gear Speed Calculator Program, are Copyright© Scott Galaba 1998 - 2008. These programs can not be copied, or used in this or any other media format without the written consent of the owner.
This web page is Copyright© Scott Galaba 1998 - 2008, this includes photographs, artwork, graphics, FAQs, Procedures, Tech Tips, and the web site logo. This information can not be copied, or used in this or any other media format without the written consent of the owner.
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