Did an experiment today.
What I did was measure the circumference of a tire at different pressures.
Why did I do this ?? I wanted to know if I could adjust out a chassis twist using tire pressure. It's similar to what the hillbillys do (NASCAR). They ad or subtract tire pressure to get the car to turn better. I am doing this to compensate for the 1/4" chassis twist in the death machine. I already took some twist out by adjusting the rear top shock mount. I unscrewed it a bit but you can't get a 1/4" because the shock rod would not be threaded into the eye far enough to be safe. There is just not a lot of thread there.

So here is the method and the results.
1) I used a worn out mud lite tire. (My brother actually likes these worn outs a lot because he can turn the machine real easy. Draw back is spin outs at speed going around a corner).
2) Wrapped a string around the tire and made a red mark on it.
3) Marked the circumference (made a red mark on string) each time I added more air.
4) Started at 5 psi because I believe that is what most of us run.

Results:
5 psi = 73 3/4"
7 psi = 74 1/4"
10 psi = 74 7/8"
12 psi = 75 1/2"

Basically: 1 psi = 1/4" difference in circumference. That works out to 9/16" diameter difference from 5 psi to 12 psi.

You may notice that when you push your machine in the shop it may not track straight.
It will try to turn in one direction or the other. A couple of years back ( I don't remember when) my brother would go down a paved road and just get the machine up to about 10 mph and let go of the wheel. It would track off left or right. Then I would adjust the front steering rods so it would track straight. Wheel air pressure was the same.

1/4" on the dirt i wouldn't worry

Rim widh also has an impact on circumference. Tire won't be as curved, rounded or arched on a wider rim.

Yes I do agree but these little machines have good feed back.
You can actually feel the chassis twist and you can feel the chassis bind.
We ride on logging roads. They're hard pack, wash board, and sometimes excessively rough with large rocks laying around. But there are areas open to some speed and corner drifts. That's where you can feel the chassis bind and twist.

CO, is this on your repaired ody or your brothers. Either way maybe take a good look at it. That's not a good sign. You being a professional driver can add more to that subject and why it's not good. I would say if you notice it that much you got issues that need resolved before a failure accures.
The only time I can remember any stressers is under exsteam load. Like coming down hard on an angle. Or the face if a jump. Any thing else I feel would indicate an issue maybe needing addressed.
I was under the impression that chassis twist or too much was very bad. If the chassis move the suspension is not doing or can't do it's job. Unless it's designed to do so.

When I say chassis bind I am talking about the feel you get through the seat of the pants when you are going around a corner. You feel it load up as you are forcing the car to turn.
When I say chassis twist I am talking about lifting the inside front tire when you are going around the corner.
It's the feeling you get through the seat of your pants because the car is talking to you.

I tear these things apart every chance I get. I love working on these machines. If anything is wrong I will fix it, just need the smallest of reasons. The only thing I won't spend money on is shocks. That's why I rebuild the rears. I know I should spend the bucks but the shock prices are just unreasonable as far as I am concerned. By the time you factor in the exchange rate and the shipping, you almost have to get a second job to pay the credit card mortgage. My credit card is ALWAYS paid off to zero EVERY MONTH -- no exceptions. So I sure as hell ain't gona pay those prices for shocks. The draw back is that the oddy's could handle better and give better seat of the pants feed back.

Thanks, so as you say load forcing it to turn.
Is that to say as the weight transfered and the way the steering wheel feels in relation to that load.

Could this be in part to the type of suspension on the ody versus the pilot. Would this have an effect on torsional stiffness? Hope I used the right word, if not sorry.

What would your opinion be on this if it was an a- arm design versurs the ody design, double trailing arm.

Wonder what the effect the two would have based on similar load in way of bind. If the tire is in the air then would it zero for traction force. So no way for it to aid in pulling the car around.
Would this also aid in overloading the outside tire reduceing it's available traction as well.
Would that help explain the feeling in the wheel.

As a driver how would one combat this as it goes into undesteer/ push. Again hopefully used the correct words.

I am not sure how to explain it properly.
To answer your first part, it's the feel you get in your bum and through the steering as the weight shifts. You can "feel" the car "load". You don't want the car to "load" up so heavy that it breaks loose or scrubs off all your corner speed. That's what I mean by chassis bind.
You want to "load up" the chassis without "binding" it and causing it to loose corner speed or go into a push or oversteer. This is why taking the correct line through a corner is so important.
Obviously your suspension design would make a huge difference in cornering.
Not really sure how to explain this chassis bind any other way.
I think there are three types of turns. If I remember right a type 1 turn is a turn that leads onto a straight. This is the most important one as you want to carry as much speed through it as you can so that you get max straightaway speed. Type 2 is a sacrifice corner where you give up speed to get a correct line into the next more important corner. Type 3 is a corner at the end of the straight. This one is important if it leads to another straightaway. If it leads to another Type 2 corner then you try to be the king of the late breakers and can "bind" the chassis. "Binding" the chassis is never a desirable thing to do because it causes you to lose speed.

I'm doing my best to follow this but I am still unsure what the fix is.

Would you subtract/add the tire pressure in both of the rear tires to make up the 1/4 frame twist or would you subtract/add the pressure in just one rear tire?

You would put air in one tire.
The left rear shock mount got bent up a 1/4" approx during that crash. You can physically see it by eye. I unscrewed the shock head about an 1/8 or a bit more. So I will just add about 3 or 4 psi more in that tire. So I will be running 5 psi all around except the left rear which will now have 8 psi.

Edit: Just to clarify -- The numbers in the pic at the top of this thread are the circumference measurements. You need to divide by 3.14 to get the diameter. So basically 1 psi works out to a little over 1/16" (.062) in diameter.

Well I got a job now, starting next Monday. It's an 8am to 4pm. I haven't had an 8hr a day job since 2002. Most have been some form of 12hr shifts. Will be working with a guy I went to high school with and we worked in the same factory as millwright shop helpers. Worked together for ten years (or more) and then he started his own business. Not sure if I like this because it cuts into all my spare time. This will also cut into my posting here LOL. Have fun everyone.

Goodluck CO - Now get to work!