bad turning radius

"Then given that, your limit of wheel width is how far inboard you can add to it before interfering with/rubbing on things." In the simplest term....Yes , as you offset the wheel to a more Positive inboard location you have to pay attention to inboard clearance at the spring or chassis. The wheel must also be able to clear whatever brake package one decides to use inboard. .........The benefit of the Positive offset wheel normally comes in easier steering and less leverage at the wheel bearings and ball joints as compared to a Negative offset wheel. Of course the math still has to be done.
The best way to complement this issue is during the early construction thought process of a project when one has a choice of axle width ( wheel mount surface to wheel mount surface IE; WMS) by either cutting or finding the correct width needed and using a wheel with an offset that does not add additional tread width and or scrub radius..........Basically a wider axle WMS but through the use of a Positive offset wheel it has less overall tread width.

"Does the addition of a spacer move your zero outboard or does it just add to the negative offset?"

It does both.......it moves the contact patch further away from the steering axis inclination center while offsetting the wheel further out which adds to the increased leverage on bearings and other steering components.

This really shows up when folks add larger , heavier 35"-40" inch tall tires with widths of 12-13 inches. In most cases it forces the individual to use a deep dish wheel or spacers to move the wheel & tire further away from any inboard clearance problems........the leverage on the spindle and related components along with the inherent increased tire wear is just the price you pay!

Not to say that you can control all of this with standard components............but at least it helps to understand it a little better.

 

Thanks, that makes sense. Kinda like my signature line, when you change something, you gotta be willing to do it so as to minimize whatever negative impacts it could cause/be prepared to do the necessary homework and mods.

 

Just for clarification purposes when we were discussing stability I was referring to vehicle dynamics in the sense that a vehicle will be predictable with minimal changes and also that the vehicle will tend to stay in one plane of motion. Example: you are traversing across the face of a hill in your Jeep. The Jeep has narrow tires on it. You feel the vehicle wants to tip sideways down the hill. This is UNstable. You traverse the same hill in the same spot with wider axles, wider tires, whatever, and the vehicle does not want to tip sideways. This is stable or stability. Another example might be a 50lb tv on a tv stand. If touched it wants to wobble and fall over. This is an example of being unstable. Put the same tv on a heavy wood dresser and it does not want to wobble. This is stable.
This is NOT a wide vs. narrow argument. They both have their places.
But, a vehicle with a wider track width, regardless of wide or skinny tires, will be more stable on the road, trail, etc. although with various tradeoffs.

Doublebit, I was simply asking for clarification trying to learn something new and certainly not "mudslinging" or whatever and it was not unfriendly.
I too have worked on tons of antique as well as modern suspension systems. Some important understanding of things like scrub radius, Ackerman principle, etc. is important for when we do make modifications. Tarry99's most excellent explanation and pics illustrate some of this phenomenally. Unfortunately in my earlier posts I had limited time and could not post more thorough explanations.

Keep in mind folks, this thread (and most threads) may be pulled up on searches in the future so the more accurate information we can post the better our information will be on this site. Which is why this is such a good site, lots of good ACCURATE information.