[Land-speed] Contact patch size

[Benn]

Awright, my 2 cents:
If your tire were a 1-mil-thick balloon, then the approach strictly using
tire pressure might be appropriate.  But tires aren't balloons--e.g. "run
flat" tires can have zero pressure and still have close to the original tire
patch.  Obviously stiffer (and/or shorter) sidewalls are required for
run-flats (I don't think they make any 70-series run-flats), so the sidewall
stiffness has a LOT to do with it.  And said sidewall stiffness will
therefore influence the contact patch....I'd be v. surprised if you found a
tire that had anything approaching a linear relationship between pressure
and contact area, unless you're looking at a v. small range.
Benn
opinion worth what you paid for it, and two cents ain't much