Maybe some of the racer/gurus out there can speak more definitively on this
subject, but
it seems to me that softer tires would exacerbate the tendency to roll - based
on this
line of logic: The high CG placement of these vehicles means there is a longer
moment arm
between the center of mass and the tire contact patch; the large mass acting
through this
distance results in a large (and aptly-named) overturning moment. Any increase
in
flexibility in the structures (suspension, that is shocks/struts, and tires)
that resist
this overturning moment results in higher deflection angles; that is - greater
displacement of the CG from center and a greater tendency to ROLL OVER!
It is exactly the combination of high CG, large mass and soft suspension that
makes SUVs
so roof-happy, especially in avoidance maneuvers at speed, when a high rate
steering input
combined with the vehicle's velocity create very high forces acting against the
cushy
suspension systems these vehicle are typically equipped with. The sudden inputs
required
to correct for a blown tire are an example of what to do if you want to put
your typical
SUV on it's roof. If it were me, I'd crank the pressure up to reduce tire body
heating on
my way to the tire store to buy some Michelins...
Gay McCormick
San Jose, CA
Pamela Pepoy wrote:
> [snip] However,
> Ford says to only inflate them to 30 psi (soft to avoid the Explorer's
> inclination to tip over and roll). Firestone says to inflate them to 35
> psi to stop them from heating up and peeling off like a bannana skin and
> also causing the Explorer to roll. So, my NEW, SAFE family vehicle is
> an unsafe, certified turkey.[snip]
> Guy
> 67.5 SPL311
> Tempe, AZ
>
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