It's really not rocket science. If you raise the pressure to the extent
that the tires round the tread, you lose traction because the amount of
rubber on the ground is decreases.
On the other hand, if you decrease the pressure so much that you cause
the sidewalls to flex, you increase the lateral movement of the car and
that is not helpful for handling. You also risk rolling the tread and
lose traction that way.
So the trick is to find that happy point where the pressure is right in
between those tow points.
Joe Curry
P.S. You never (as was pointed out) want to exceed the manufacturer's
recommended inflation pressure. They obviously know more about their
tires than we do.
DANMAS@aol.com wrote:
>
> In a message dated 98-08-15 14:52:02 EDT, gernot.vonhoegen@stir.ac.uk writes:
>
> > while I agree with the thread on pressures, I disagree with the
> > improvement in handling due to higher tyre pressure. Typically the
> > improvement is a lower pressure. Higher pressure will give you a better
> > fuel economy when you drive on motorways where you don't expect much
> > cornering etc. If you want better handling, you will find that dropping
> > the pressure by about 5 psi below the recommendet setting will improve
> > matters. However, that depends on the individual tyre make due to
> > different grip and wear qualities.
>
> Gernot,
>
> I'm no expert (not even close), but according to Fred Puhn, author of the book
> "How to Make Your Car Handle," higher pressure will improve handling. I quote
> from the caption to figure 4, page 19:
>
> "Notice that you lose more by a small amount of underinflation than a small
> amount of overinflation. When in doubt, increase the pressure before you try
> decreasing it."
>
> Figure 4 is a diagram plotting grip vs pressure. Grip drops off much more
> sharply on the low pressure side of the curve than on the high pressure side,
> using optimum pressure as a reference.
>
> In the few years I hung out with the SCCA showroom stock racers (as a
> photographer for a local TV station), I was amazed at the high pressures they
> used - often in excess of 45 psi, all on street tires.
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
> http://www.sky.net/~boballen/mg/Masters/
> '74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
> '68 MGBGT---organ donor for the '74
--
"If you can't excel with talent, triumph with effort."
-- Dave Weinbaum in National Enquirer
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