Assuming pretty arrows are force vectors in post 115 why are they pointed to the unloaded wheel? The forces go from inside to outside and the percentage that is vertical is a result of all those un needed details. The forces go from inside to outside wheel. The amount of vertical is a function of the roll center height and CG height and the lever arm it creates ignoring anti dive. I suspect I am not the one with my head in the sand.

BTW where did the displacement data come from for the pretty pictures with painfully low wheel rates that are more suitable for a little red wagon?

This has actually become a source of amusement following theories of things that don't actually happen short of the spring moving some unknown amount so far on the inside wheel.

 

You are when you throw down "I'm a 200 mph IMSA racer so I'm the rightest, I'm not going to listen to anyone else!" That is precisely stuffing your head deep into the sand.
Here's the part that you're missing, at this point; we're talking about the spring and what it can do. That is all we're talking about. In post #115, the illustration is of the spring. That's all it is! There are no control arms, no suspension geometry, no roll centers....it's just the spring in the illustration, to show what the characteristics of the spring, are. The illustration attempts to make a visual representation of what is happening with the spring, in operation. It's there so you can "see" what is happening to understand it. This isn't about "spring moving some unknown amount so far on the inside wheel"...in the car, the spring may not move at all....but the downward force in the inside wheel decreases, as compression on the outside wheel increases. Just as happens w/the sway bar hooked up.



You're right about this part...at least.

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You can repeat this all you want and you will still be wrong. You are confusing wheel rates with weight transfer and suspension motion during lateral acceleration. We aren't talking about weight transfer, or tire loads at all for that matter. We are talking about static wheel rates in roll vs wheel rates in heave/pitch. That's it. RC and CG locations have absolutely nothing to do with it.

Wheel rates remain the same whether the tires have loads on them or not, and regardless of what motions or forces are acting on the car at any given time. Static wheel rates are a function of the sum of all springs acting on each corner divided by the motion ratios of each of those springs.

You are literally correct that this thread has become a source of amusement. Currently a highly placed IndyCar engineer and an aftermarket suspension engineer (not fabricator - engineer), with whom I am friends, are both getting a good chuckle out of your moronic posts. There might also be a physics major who is also a rocket scientist doing the same thing, but I haven't asked him yet.

 

Tom is correct, this is only a model of a spring for demonstration purposes. While you are correct that the load on the tires is the result of lateral forces as well as static load (assuming no longitudinal acceleration) at the end of the day the forces applied to the springs are roughly vertical with respect to the chassis. Yes, the spring rates aren't realistic. Then again neither is the simple spring shape (a constant section arch of homogeneous material). I also used a linear solver in a case where deflections were large. As Tom said, this model only illustrates the point.

Anyway, note a few behaviors that are "anti-roll bar like". For instance, notice that when 100lbs is applied to both sides they each move up 8.6". But, when only one wheel is pushed up with that same 100 lbs we see less deflection but we see the unloaded side move up as well. That looks like the behavior of a traditional suspension with an anti-roll bar.

We have a system with an equivalent ride spring rate of 11.6 lb/in. And I think we would all agree if this were a two coil spring model with a 11.6 lb/in spring rate we would again see 100 lbs displace both sides 8.6" and the connecting anti-roll bar would show no twist and have no impact on things. However, with that conventional coil + bar setup we would expect pushing up on just one side would cause the sway bar to twist a bit pushing "up" on the unloaded spring and "down" along with the loaded spring. Thus, when only one wheel is loaded the coil spring rate + the downward force from the sway bar effectively make the total spring rate on the loaded tire higher. At the same time because the sway bar is pulling up on the unloaded side it will compress the spring a bit on that side.

What do we see in our 100 lb, 0lb case, we see the loaded side doesn't displace as much (ie the total spring rate is higher) and the unloaded side moves up, just like our sway bar case.

GM says it happens this way. Other say it as well:
Honda in a 1988 patent says a similar configuration does away with conventional ride springs + stabilizer
https://docs.google.com/viewer?url=p.../US5141209.pdf
I believe Ford and Porsche have similar patent descriptions.