How to Find the Weight of a Car
The weight of your car affects its handling on the road. As "Grassroots Motorsport" magazine reports, any car used for racing can be customized to distribute its weight in the most advantageous way. For the regular motorist, it's important to know your car's weight limitations. A car carrying too heavy a load may be hard to steer and the tires may be prone to blow-outs. Since 2006, manufacturers have included a decal on the driver's door stating the maximum safe load of passengers and cargo that can be carried.
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Things You'll Need
- Tire pressure gauge
- Notepad and pencil
- 2 manila folders
- Ruler
- Calculator
Instructions
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Measurements
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1
Park the car on a piece of dry, level ground. Make sure the parking brake is set.
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2
Unscrew the valve cap from the front right tire. Press the tip of the tire pressure gauge against the exposed valve. You will hear a hiss of air and the the tire pressure will be shown on the dial of the gauge in pounds per square inch. Make a note of the reading with a pad and pencil, for example: "Front right, 32 psi." Replace the valve cap and check the pressure in the other tires, making notes of your findings.
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3
Push manila folders under the two opposites sides of the front right tire, as far as they will go. Measure the distance between the two folders with a ruler. This will give you the width of the part of the tire that is pressing against the ground. Make a note of the measurement, for example: "Front right, width 4 inches." Remove the folders.
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4
Push the manila folders under the front and back of the same tire, as far as they will go. Measure the distance between the two folders with a ruler. This will give you the length of the part of the tire that is pressing against the ground. Make a note of the measurement, for example: "Front right, length 7 inches." Remove the folders.
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5
Measure the length and width of the other tires, making notes of your findings.
Calculations
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6
Work out the area of each tire that is pressing against the ground by multiplying the length by the width for each set of figures you noted. Use a calculator to help if necessary. Make a note of the result in square inches, for example: "Front right, 4 inches multiplied by 7 inches. Area: 28 square inches."
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7
Work out how much weight each tire is holding up, by multiplying its area by its pressure reading. Use a calculator to help if necessary. In the example of the front right tire used here, you would multiply 28 (the area in square inches) by 32 (the pressure in pounds per square inch). The answer will be in pounds. In our example, it would be 896 pounds. Make notes of your results.
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8
Add together the weight held up by each tire. The total you get is the weight of your car. For example, you might add figures similar to these: 896 pounds, 894 pounds, 895 pounds and 897 pounds, giving a total car weight of 3,582 pounds.
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1
Tips & Warnings
Check the decal, or sticker, on the driver's door for the maximum load the vehicle should carry.
If you do not have a tire pressure gauge, you can measure your tire pressure at a gas station.
Check the owner's manual for your car to find information on its "curb weight," or how heavy it is without passengers or cargo.
References
Resources
- Photo Credit pression des pneus image by Nath Photos from Fotolia.com
