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Clever car weight determination

Old 05-22-07, 01:50 PM
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Clever car weight determination

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Anyone that knows their car's weight from an actual scale wanna try this and report back for the rest of us in towns that don't have corner scales?

Curious how accurate it could be. . . lots of variables that decrease its validity

It'd be interesting to see.
thanks
ryan
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Old 05-22-07, 04:14 PM
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Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
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Old 05-23-07, 06:23 AM
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Originally Posted by jgrewe View Post
Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
But if all of the tires are the same size and model you can get a very good approximation on corner weight percentage.
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Old 05-23-07, 07:13 AM
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Tires with stiff sidewalls will also throw this calculation off. You also need a very flat smooth surface to do this on.

But as a first order approximation, it's probably not too bad. My gut feeling tells me it's possibly good to +/- 100 lbs or so on each wheel. If I get the chance I'll try and remember to try this out on the FC (which is corner balanced and I do know the weights).

The engineer in me cringes when he sees them carrying their calculations out to seven significant digits - implying accuracy where there is none.

-bill
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Old 05-23-07, 10:58 AM
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this is prolly good if you've already built the car, and are just setting it up....
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Old 05-23-07, 05:27 PM
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They said "if you get within 10% of the weight stated in your owner's manual, good job!"


10 percent on my car would be about 279 lbs; I don't think any of us would be satisfied with the results. I've measured corner weights on a set of racing scales, so maybe I'll try this just for kicks.

-s-
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Old 05-24-07, 08:45 PM
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Originally Posted by jgrewe View Post
Good for general idea of weight but as you say the variables will kill the accuracy. The biggest being the contact patch isn't a rectangle.
I just tried one of the tires, and yes, the contact patch is not a rectangle.

I had a feeling my calcs were going to be off as I could see how much surface area fit inside of the "rectangle" but didn't touch the tire.

My car weighs about 2700lb, and I got 1000 lbs on one corner using the calc.
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