What I'm saying is, if I change to springs of a different stiffness, the scales under the tires will read the same as before, assuming all the springs weigh the same.
You can put pipes of equal weight in place of the springs and the scale readings will not change.

I don't think a formula is needed to see that.

To bring this back around to the original topic...
The springs won't affect the tire diameters on a standing vehicle.

 

So if you hold 50 lbs a foot off the ground it's going to weigh something different 3' off the ground?

 

Whether it's a ton of feathers or a ton of bricks, it's still 2000 pounds....
This is why tradesman always laugh at engineers....

 

I'm glad you guys are enjoying this after you asked me to further explain.

You guys are correct that 6000lbs of weight will weigh 6000lbs. The part you seem to be missing is that there are 4 tires on the ground supporting that 6000 lbs and how that weight gets distributed between those 4 tires will be different depending on the height and stiffness of the different springs used on a JK.

So I'm glad I could humor you guys with an obvious feeble attempt by responding to your request, even after attempting to dumb it down into simple to understand examples.

Yeah, simple minds think simple and can't understand a simple thing known as weight distribution. Stupid is as stupid does.

And this is why engineers just shake their heads at the tradesman and say it isn't worth going on trying to further explain, while we collect our nice size paychecks and call the tradesman to come fix our toilets because we have better things to do for a living than cleaning up other people's sh*t.

 

I'm not enjoying this at your expense. I'm trying to get you to see the stiffness of the springs will not change the weight on the tires.

Now, if you jack up the rear and leave the front low, sure the cg will shift forward a little, (very little), but simply changing to stiffer or softer springs won't change the weight on each tire as the jeep sits on the scales.

 

15 posts and not a single person has responded with the information the OP asked for. These threads always fade away from lack of participation, so beating the specifics to death really doesn't solve anything.

How about just specifying that the measurement is taken from the spare and forget about weight and coils and distribution and engineers vs tradesmen and whatever else that no one is willing to agree on?

 

I don't understand the obsession with trying to find out if X brand tire is 1/4in taller the y brand when your jeep is sitting on the ground. There are way to many variables to try and worry why your buddy sits 1/4 taller than you because you bought Y tire instead of X.

Go out and enjoy your Jeep the way it is.

 

Great idea!
However, there is quite a difference between a new spare and one that been getting rotated into the mix.


I am thinking the same thing.

 

This is the exact same thing I'm saying will occur with different springs being present on different JKs. The weight distribution will change depending on how the Jeep is sitting and how the Jeep sits absolutely is a function of the springs used. So what is it that you're really trying to get me to understand? You want me to understand that there's no such thing as different forward and rearward bias rakes on the different Jeeps on the road due to their different springs? Is that really what you're trying to get me to understand because it certainly seems like it?


Example 1: Which point has more weight on it? A, B, or the Same?


Example 2: Which point has more weight on it? A, B, or the Same?


Did the CG change between Example 1 and Example 2?


I'm hoping this is now simple enough to understand, where even a furniture moving tradesman can understand it, if they've ever worked in a 2 man team moving a couch. This couch just happens to weigh 6000 lbs.

What you're currently telling me is that your answers to Example 1 and 2 would be "The same". Is that really what you're saying and trying to get me to understand?

 

That would have been my proposal all along to remove the majority of the different variables. I would have also suggested to perform the measurement taking a circumference measurements to reduce likely measuring variable errors, but what the hell do I know? I'm only a dumb engineer wasting his time trying to explain things to the likes of some Beavis and Butthead jokesters.