DIY weigh your car

[Garageaholic]

I found this article online. What do you guys think? i think it's dumb and there are many more variables than is described. Your thoughts?

"To weigh a car, take two sheets of paper, a ruler, and a tire gauge to a smooth, hard-surface parking lot. Find the car you want to weigh. Slide one sheet of paper under the front of a tire as far as it will go. Slide the other sheet under the back of that tire as far as it will go. Be sure the two sheets are straight. Then measure in inches this length of the tire’s “footprint”. Slide a sheet of paper under the outside of the tire as far as it will go. Slide the other sheet under the inside as far as it will go. Be sure the papers are parallel (straight). Measure this width (distance between the sheets)of the tire’s “footprint” in inches.

Multiply these two measurements to find the area of that tire’s “footprint” in square inches. Then press a tire gauge on the valve stem to find the air pressure inside the tire in pounds per square inch. If you need help, ask your teacher or another adult who has taken tire pressure before..

When you know the air pressure inside one tire, and the area of its “footprint,” you should draw a rectangle the size of that tire’s footprint. Mark this area into square inches. On each square write the pressure inside that tire. When you add up those pressure-per-square-inches, that is how much that tire is holding up. Do this same thing for each of the other tires. When you add up all four tires’ hold-up force, that is the weight of the car! What do you think happens to the area of each tire’s “footprint” when several people get in the car?"

[asubimmer]

or just go to a weight station lol

[mrsleeve]

^^^^^^^^
thats the way I would do it!

[browntown]

Ummm, no. Might be a good estimate for a kid's school project, but yeah go to a weigh station. There are unmanned ones on the little highways around here you can just drive up and look. Also the local recycling center (read: county dump) charges you by weighing your car in and out, they actually use fairly accurate scales there, and give you a printout with the weights.

[Garageaholic]

haha, i didnt' know that!. i'll give that a try next time im on the highway..

Do dyno's weigh a car also? do they have an internal scale?

[schmidty]

you think they'll get mad if you pull up to truck weight station and ask them to weigh your car? :p

how accurate of a reading do they give anyway? I would think that since they are made for semis they wouldn't be the greatest for cars? and don't they have two plates? one for the front wheels and one for the trailer wheels?

[euroshark]

You can weigh your car at the dump. My buddy had his '78 F250 (428 Cobra Jet ) weighed at a dump and it came in at 4700lbs, probably fairly accurate.

[JGood]

Check any local company that sells large quantities of products. Mulch, cement, etc... Most have scales.

That method is not good for our purpouses. Camber and tread block design variables would never let you get accurate readings.

[AdironRider]

Its not the most accurate (I did the experiement in high school with my car) but its pretty good to within 100 pounds. When I calculated it I was off by 87, other kids were as close as 50 or off by as much as 200. THeres a bunch of human error involved, mainly in the measurements as its easy to add a couple square inches via inaccurate measurements.

[325Projectz]

haha, i didnt' know that!. i'll give that a try next time im on the highway..

Lol, as he puts away his paper & ruler.

[Jscotty]

I have gone to the dump and to the industrial lot where they make sand and gravel and in both situations the weight is rounded off to the nearest 20 lbs.

[backtrail69]

My Eta was 2680 the last time I weighed it. All stock (interior/engine wise) Suspension is highly modified...with euro bumpers.

[uofom3]

yeah just got to a weigh station. I clocked my red m3 in at 2820 witha full tank

[ANDRÜ]

Its pretty clever for someone to think that up, but there are too many thinks that effect your calculations.

[Mot]

it really is easier to just find a weigh station, thats how I weighted my car for the other thread I made.