weighing a car - Moparchat

pishta · #1 05-12-2007, 01:02 AM

If you put a car on a scale, itll give you to total weight. How do you find the weight of the front end? I mean if you put the car on 2 scales. front and back and add the weights, do they add up to the total weight? 4 scales at the corners? This just sounds wrong.

wedgehead · #2 05-12-2007, 08:50 AM

This is what I did. I got the total weight of the car, then pull the car up as to get the weight of the rearend(only rear tires on the scales). Calculate what percentage of the rear of the car is to the total weight of the car. Ex: Car weight-3000 lbs. Rear of Car-1500 lbs. Then your weight distribution is said to be 50%. This is what really makes a car hook!! You want the weight distribution to be 48-50%. Most cars will only be in the low 40's. Sometimes you may even have to add weight to the car(trunk area) to bring the weight distribution up where it needs to be. Wedgehead

wedgehead · #3 05-12-2007, 08:57 AM

Sorry, you asked about frontend weight. This will be the difference of the total weight of the car minus the weight of the rearend. Having trouble hooking? A 451 can be a bit heavy in a 65 Barracuda. You're probably nose heavy. I own one. To get it to hook with a small block in it I had to add weight to the rear of it. I placed a piece of railroad tie in the very rear of the trunk area and had it welded in. Made it a different car!! Car started doing wheelies!! Wedgehead

Kevin Garceau · #4 05-12-2007, 10:17 AM

Most stock type chassised cars are going to be nose heavy, no way around it.

When I had my big block in my dart even with battery in the trunk, cell in trunk, and as much weight removed from the car as I could...it was still 52/48

Dont try to weight it on a truck stop scale, they are so far off. Either take it to a track that has a scale or find some stock car racing guys...the ALL have scales. All good scales that chassis shops, drag racers, or stock car racers have are all 4 corner scales. It is the best way to weigh the car, it will show you if you have too much weight on one corner etc.... this is where you make chassis adjustments, preload, coil spring adjustments etc.....

dwc43 · #5 05-12-2007, 10:28 AM

Quote:

Originally Posted by pishta

If you put a car on a scale, itll give you to total weight. How do you find the weight of the front end? I mean if you put the car on 2 scales. front and back and add the weights, do they add up to the total weight? 4 scales at the corners? This just sounds wrong.

We have tried it before and it wont work. It's not accurate at all. You need a 4 wheel scale set up to get the proper weights for the car. And most all good 4 wheel scales will show the total plus each individual wheel and percentages front and rear and side and cross on the best scales. You'll want to get 53 to 55% rear weight to get your car set up correcctly. Most likely you will need a large amount of lead to get it done properly.

John Kunkel · #6 05-12-2007, 04:50 PM

Quote:

Originally Posted by dwc43

We have tried it before and it wont work. It's not accurate at all.

Care to explain?

I've rolled cars on platform scales one axle at a time and the front/rear weight equals the total every time. The only way there would be a discrepency is if the wheel surfaces aren't at the same level.

Truck scales weigh one axle at a time for axle/weight law enforcement and their numbers stand up in court.

Kevin Garceau · #7 05-12-2007, 05:20 PM

When I say a truck scale not being close I mean they are not calibrated for small weights such as 3200 lbs.... they are designed for much bigger weights.

dwc43 · #8 05-12-2007, 10:49 PM

Quote:

Originally Posted by John Kunkel

Care to explain?

I've rolled cars on platform scales one axle at a time and the front/rear weight equals the total every time. The only way there would be a discrepency is if the wheel surfaces aren't at the same level.

Truck scales weigh one axle at a time for axle/weight law enforcement and their numbers stand up in court.

For one, as Kevin mentioned they are not designed for smaller weights. Two, they will jamb the scale plates if there is any side load as well. Also try weighing left side and right side weights with only the two side wheels on the scale. They wont total up at all. And yes, the level of the surfaces also make a difference.

And as for using single truck scales, they are not accurate either. And there's a lot of things that hold up in court that should not and there's a lot of things tossed out that should not be. That's just how the system works. Flawed, yes, but better than any other system around, plus it has nothing to do with weighing cars.

John Kunkel · #9 05-13-2007, 05:15 PM

Quote:

Originally Posted by dwc43

For one, as Kevin mentioned they are not designed for smaller weights.

Don't paint all truck scales with the same brush.

I pull my loaded dump truck on the scales at a rock plant, step out to sign the invoice and walk across the adjacent scales which have a digital readout on the scale house in five pound increments and it shows my "smaller weight" quite accurately from side to side and end to end (I like to play on the scales).

This certified scale will issue certificates of weight on anything from a bicycle to 120,000 lbs. "overweight" loads and they'll be accurate to within .2%.

Slant Cecil · #10 05-14-2007, 08:48 PM

At one time there was a self serve (honor system payment box) truck scale at a nearby closed down truck stop. The scale was an old mechanical unit. As long as it was zero'ed in before using and place the car in the middle, it would weigh our cars within 5 lbs of the track scales reading. It would also give your body weight within a few lbs The newer electronic scales self-zero, I would think they are accurate most all the time.