[CapriRacer]

Originally Posted by RidingOnRailz

I ran the calculations using the formula posted elsewhere in this forum, assuming original size tire on a 2WD 1997 Explorer(using GAWRs from the placard image in the Barry's article you linked to). ……

So first off, that formula is faulty. The formula used by the tire manufacturers is quite complex, which is why they publish charts - which is where I got my values.

Here's a version of that chart:

https://www.toyotires.com/media/2125...s_20170203.pdf

Yes, it is from Toyo tires, but the chart is the same regardless of who manufactures the tire. (and for completeness sake, there is some complication that makes it harder to understand. I go into more detail here):

http://www.barrystiretech.com/tirest...izingorgs.html

Originally Posted by RidingOnRailz

…….. Specifying the 2WD 1997 Explorer on TireRack, the recommended tire is 235/75R15, 105T, Max load 2,039lbs at Max cold pressure 44psi: ……..

No, do not use the max pressure for anything other than the max pressure.

Originally Posted by RidingOnRailz

…...

FRONT = 2,510/2 = 1,250/2,039 * 44psi = 26.97 cold (27)

REAR = 2,900/2 = 1,450/2,039 * 44psi = 31.28 cold. (31)

…….

No, the 44 psi value is not tied to the 2039# value. The 2039 value is tied to 35 psi.

So if you use the correct 35 psi value, you get 21.46 psi front and 24.88 psi rear.

Originally Posted by RidingOnRailz

…… So the formula suggests significantly higher rear cold pressures, and only a slight bump up in the front pressures, presumably to maintain steering feel. …….

But if you use the correct values, it says the pressures were OK. Don't forget that the government (NHTSA) looked at all this and had the tires recalled, not the vehicle.

Originally Posted by RidingOnRailz

……. Most large legacy rear-drive vans(think: Econoline, Express, B2500), run at least that front-rear difference, if not at least 20psi higher rears than fronts. …..

2 thoughts:

First, those are vans, not SUV's

You are pointing out vehicles that use LT metric tires, Look up the base vans that used P type tires (E-150, B1500, etc.) and you'll find a different story.

Originally Posted by RidingOnRailz

….. I still implicate the low pressures on those Explorers as at least 60% of the culprit in those tread-sep/blow-out cases. Those cross-section photos(Figure 9) in the Barry's article could have been of any tire, from any vehicle or tire mfg. We'll never know definitively.

Those photos were in Dr. Govindjee's report and were published in the NHTSA EA00-023 report used to justify the tire recall. Are you implicating that NHTSA (and Dr. Govindjee's) didn't use photos of the tire in question when they had abundant samples available?

Oh, and I don't think you've yet realized that I am Barry.