Right front ball joint

[HEAVY DUTY]

I see what you mean about the roll center moving front to rear. I have a 3 dimensional front end program that should account for that somewhat. I heard that Larry Moore once said," if you bolted a solid bar with hiems in place of the lf shock, where would the roll center then be?" The car would have to rotate around the shock mount on the LF a frame, or the LF tire patch, regardless of where the instant centers of the front a arms were. What about the roll center when the lf tire lifts off the ground? Most of the good roll center programs are figuring a force based (loaded) suspension and taking jacking forces into account, and assume that the car is semetrical side to side, with the spring rate and weight equal from side to side. I personally don't believe that the roll center is a solid pivot point that the front end moves around, like a lot of people teach, and that the spring rates have to play a part in the front roll centers.

[Lizardracing]

Tires act like springs too so how does that adds to the complexities of calulating RC's

Because dirt track surfaces are generally pretty eratic in the terms of calculating RC locations(bumps, banking, car attitude) are constantly changing than I surmise that RC locations are more of a generality with some useful info but by far any absolute. Finding practical application for the knowledge will be needed.

Maximizing the average contact patch and wheel loading to balance the car front and rear for driver preference and tire wear through Camber, Caster, and Bump Steer has much more impact on the common racer than current RC theory in my opinion. Maximizing the drivers ability to feel the car traction limits and provide quality feedback for adjustment purposes is probably even more important than anything else.

[1Blacksheep]

Back when we raced solid front axle Micro sprints we adjusted Dynamic turn ability with Springs and left the front pan alone. We could not give a Ratts Azz where the MOMENT Center was especially when the Left front tire was only for getting the car to the green flag and the first 10 ft of entry to the corner. The rest of the time it hung there for ballast .You can safely bet your Hiney springs effect the SAID MC ! Which is just a Thought Guide to start with . IMO

[Lizardracing]

I got to studying an Indy car the other day my local University builds in the engineering dept and I pondered the question. How do they calculate RC and MC when the upper and lower control arms are parallel and don't intersect to create the IC to map the RC?

[1Blacksheep]

I got to studying an Indy car the other day my local University builds in the engineering dept and I pondered the question. How do they calculate RC and MC when the upper and lower control arms are parallel and don't intersect to create the IC to map the RC?

That's some canti lever stuff that when you connect all the lines the IC points to the RC which falls somewhere between the Big and Little Dipper ! LOL just kiddin

[speedbuggy]

I got to studying an Indy car the other day my local University builds in the engineering dept and I pondered the question. How do they calculate RC and MC when the upper and lower control arms are parallel and don't intersect to create the IC to map the RC?

Do you really want an answer to this or you just joking around?

Smart as you are, I think you already know the answer. Just consider that the IC's are infinitely distant from the contact patches. At least, that's how I would look at it.