<VV> The Radial Conundrum (long)

[Rick Loving]

You will get many answers.... the largest majority will recommend a
6-10lb difference front to rear and a small group will say same all
round is fine.  They may all be right for there driving style and car
setup.

The true answer is that the tire pressure is dependant on the tires you
have bought (sidewall strength), your driving style, and your
expectations of the ride quality.

You didn't mention what year your vair was...generally 60,61-63, 64, and
65-69 will exhibit different driving experiences due to the suspension
changes that occurred during the different years.

The lower tire pressure in the front helps reduce push or under-steer
while cornering, under the situation that your driving style is
aggressive enough to exceed the traction that the light front weight of
the Vair is putting to the ground.  The higher pressure in the rear
keeps the sidewalls from rolling under due to cornering forces generated
by the tail heavy, pendulum like swing of the rear end during corning.

The lower pressure range allows for the sidewalls to "yield" and act
like air cushions in addition to your shocks.  The higher pressure range
increases the sidewall stiffness and allows for a higher limit of
driving performance.

I personally run 22 front and 32 rear in my 63 vert.  The vert is
heavier than a coupe and I keep my spare and toolbox in the front and
generally drive more aggressively than the average driver (think cab
driver).

Keep in mind that 99% of the time you will not need the traction and
handling that proper tire pressure will provide, but the 1% of time that
you do need it is when you are in an emergency situation and your life
or others may be on the line.

To test your tires, once installed, fill them to around 18-22 front and
28-32 rear, take some shoe polish and smear it in right at the edge of
the sidewall and tread at 4 spots around the tire on all 4 tires.

Find a big (empty) parking lot and start driving around.  Act like you
are doing a driving test and make a series of 90 deg turns and "U" turns
continue to increase the speed and tightness of the turns until you feel
the handling characteristics of the car change (under-steer or
over-steer)

Check the polish on your tires and see if the sidewalls rolled enough to
be in the polish, too much roll means you need more air, no roll means
you need less air.

You will also have to decide on ride comfort level as the higher
pressure makes the car handle better but ride a little rougher.

Rick Loving
63 Vert
63 Coupe
64 Coupe
65 Coupe 

<SNIP>
Subject: <VV> The Radial Conundrum

Hello again, groupies.

My question is about the best tire pressure.  I've been told that too
little
pressure in a radial will damage the steel belts, and on the other hand,
radials.. in a perfect world should have approx. equal pressure in all 4
tires.  I think 15 psi in the front is too low for radials, so I
currently
have about 20-22 psi in the front, and approx. 28 psi in the rear tires.
I
do only normal driving around town and on the H-way.  The tires feel
fine,
etc., but I seek the "wisdom of the group" on whether there is an ideal
range for air pressure.