[quote=“Ranger” post=64489][quote=“juliancates” post=64382]
Things that could possibly be distorting my findings:
- I didn’t fill the tires to race pressures.
- I don’t have my weight in the car.
- I didn’t unhook the sway bar.
That said… could they really be making THAT big of a difference that I couldn’t even get close to zero toe?
Potentially useful info. None of the “* I didn’t…” should matter. A year or two ago I experimented with how toe might change with suspension travel. I wanted to know if suspension compression added some toe-in, which some folks say is desirable. This is discussed in detail in some old thread but the bottom line is “no, toe doesn’t change with any reasonable amount of suspension travel.”
Note that my method of measure toe multiplies the delta by 6x so if there was the tiniest amount of toe change, I’d have seen it. IIRC my conclusion was something along the lines of…“there might be a little toe in added during significant compression but it’s so tiny that I can’t be sure.” My ability to resolve absolute toe is prob 1/3 of a mm, which might as well be zero.
In a somewhat related issue, yesterday I did a quick experiment to see if camber changed due to air pressure. I think that it’s common wisdom that camber does change if you add air, but I’d have to say that I’m not sure what the physics are behind that. I figure that if you measure camber on a flat surface, and then measure it again after moving the car on to a 5mm platform, there’s no reason to expect camber to change. And shouldn’t the 5mm platform replicate putting some more air in the tires?
All I can say for sure is that if you go from 24psi to 34psi, the difference in camber is too small for my device to measure.[/quote]
I can’t see the toe staying the same unless you have solid bushings and 0 bump steer. I don’t think these cars have this with the lowered suspension, but hey I haven’t measured it yet.
Typically, I’ll just take the measurements from tie rod to tie rod, estimate a center point and take measurements from there and input to a CAD model. Then you can pretty easily tell exactly how much the toe will move given a linear amount of jounce.
Couldn’t see tire pressure making much of a difference in static camber. The difference would be the increase in stiffness of the tire and resistance to the tire rolling under given the large amount of camber gain built into a strut type suspension.
Interesting experiment though.