Noone learns much from discussions they can't read, so I'm trying to make this open. This disagreement began in Smudge's 2.7L Tacoma thread, and I guess I did feel slighted, when my laborious testing was refuted. CapriRacer kept his cool better than I did, and I should have done better.
Even so, The issue is how many times any given tire actually turns, per mile. Some thing revolutions, some think rotations, I'm side-stepping that mess with turns, to keep the focus on the real issue.
So I'm going to start by detailing my testing, that will be a long read. But it took a lot of physical labor, and I am clear on the scientific method; establish a baseline, repeat to confirm, change only one variable, test again, then repeat to confirm. Then go back to the baseline, by undoing the change, and see of original test results repeat, and re-test that. I did all that. Took me a long summer saturday and plenty of Gatorade, just for the first test.
That was a C2500 pickup truck on LT245/70R17E tires, then after that, I realized I needed a subject with short-sidewall, non-LT tires. I had an Isuzu mini-truck available, and I had a set of P245/50R16 tires. So I tested that as well.
I know a place with just over 2/10 of a mile of straight, flat, level asphalt and no traffic. Farm country. I took gloves and 2 shovels as well as my Gatorade and sandwiches, and I took my then girlfriend and her brother. He borrowed one of those measuring wheels on a long handle. You walk, it rolls and shows distance.
It was about 70 and overcast when we started. At the local salvage yard, their scales showed my C2500 had right at 2000# on the rear axle, with nothing in the 8' bed. So while she went marking distances with that device and some chalk, I equalized the rear tires at 78 psi.
Chalking a mark on each rear tire wasn't hard, Once I had one beside the first mark on the pavement. I had her drive at walking pace. Us guys counted. Then he drove back, us lovebirds counted. Multiply that by 5 to equal a mile. I lost the notes a few weeks after I had my answer, I had no idea I'd ever need them again. All that mattered to me was I got proof that the advertised numbers are always wrong.
In fact, get on
www.tirerack.com, find a size with 100 or more choices, and you'll find no consistency there in r/mile even when they're all the same diameter.
Anyway, Baseline in hand, we shoveled dirt until the bumpstops touched the axle. Never got a weight, but the tires were bulging. And the count was the exact same. Why? Because the circumference didn't change, only the vertical measurement from the center of the hub down to the road. Whatever the circumference is, that's how far you will travel for one turn of the tire, unloaded or overloaded. This is basis physics. It can't be refuted, and that's why my gal thought the day wasted. All we did was confirm what the math told us.
Same deal again wit the Isuzu. She didn't help that day, nor did her brother. I had to bribe another friend with a steak dinner.
Maybe I got over invested in something the average Ecmdder doesn't need to think about. But I'll not be told I'm wrong when an independently verifiable test proves I'm not.
Fir all your future calculations, use measured circumference, if need be divide by Pi for diameter, divide diameter by 2 for real radius. Then if there are discrepancies, you'll know where it can't be.