There isn't enough sidewall strength on even an E load range tire to change tire height unless aired down. If you have a thousand pounds sitting on top of a 25psi inflated 10" wide tire the contact patch is going to be 40 square inches regardless of whether it's a C or E load range tire (1,000lbs/25psi=40" contact patch, 4x10"). Only when you have aired down to the point where the sidewall exceeds the psi of the inflation rate will you change tire height.

I've never actually tried anything scientific but it takes less than 25lbs per square inch of pressure to flex an E load range tire's sidewall.

 

So basically a C will ride softer on road and not have as strong a sidewall off-road??? Will a C range tire wear quicker than a D range or are they both pretty much the same? I can't imagine theres that much of a difference and at this point I am leaning more towards a C range on the JK, but if they wear super-fast, I can put up with a D range for the extra mileage. I guess it depends more on the tire maker than the load range???

 

More sidewall flexing equates to more heat. More heat equates to quicker tire wear given the same compound. Stiffer side walls and the appropriate tire pressure (about 30lbs for 34" tires) will make the ass end less flighty, especially on a 2 door.