Hi, Mike....
Traditionally, the larger the "footprint" relative to the "stock"
footprint, the lower
the tire pressure in terms of load upon
the shocks, springs, etc.
IOW, for any given "shock" to the car
caused or originated by the road surface
to the vehicle, the "harder" it will impact
the vehicle the larger the footprint at
the same tire pressure, all other things being equal.
(Now, I am not an engineer. This is what
I have been led to believe. So if there are
engineers or others out there who know
differently, please pipe up and we'll all
learn something, inclusive of your's truly!:)
So, I would start with the STOCK pressures (cold) and see if the ride is
too harsh, 'cause underinflation is not
a good thing either (causes heat buildup).
You really want the performance the tire
is capable of delivering with the larger
footprint without beating the hell out of the
suspension parts. So a lot of this is really
"tailoring" to the road surfaces you normally travel over.
The sidewall shows the max. pressure for
the tire. Generally for the road, this is way
above what you will be using considering
comfort and wear and tear on shocks, springs and suspension parts in
general.
Anything under 20lbs. is going
into "underinflation", wherein the tire begins squirming as it travels
and high heat buildup occurs.
So I would go with stock to begin with and
get a feel for this tire/wheel combo to begin with. Then I would begin
upping the
pressure in two pound increments (front
and rear) until the ride started getting
rough and/or uncomfortably "bouncy".
At that point, back off a bit and you are
"there" for your application and personal
taste.
While you don't want to beat the hell out
of the car, handling in terms of crispness
of response as well as grip will be better
at the higher end of the "acceptable" range, as will fuel economy due to
less
rolling resistance ("peppier" vehicle).
So you do want to be up toward the high
end of what is acceptable to you, rather
than the low end of acceptable.
Cap'n. Bob
'60 :{)
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