Re: [DML] Re: Goodyear tires

["Hank Eskin" <heskin@xxxx>]

> Well right now my Eagle GT II tires are at 40/40 the tires say 44 max
> psi. Are they up to high?

Yes, and here's what I was taught about tire pressure and how it relates
more to car and it's load than the whatever is printed on the tire. (This
analysis might be flawed, but it we argued this point at work for weeks, and
finally came to a consensus with the help of a couple of physics majors - if
it is way off base, kindly correct.).

Assume the curb weight of the Delorean is 2,712 pounds, with a 35/65
front/rear distribution (From the Delorean FAQ). That means that each front
tire supports approximately 475 pounds and each rear tire supports 882
pounds. Under the Delorean recommendations, the front tires should be 23
PSI. If you divide 475 lbs by 23 PSI, you will get a tire contact patch of
20.65 square inches. For the rears, you will get a contact patch of 29.4
square inches. (If your tires are properly inflated, and you accurately
measure the area of your contact patches, you will come very close to these
numbers - trust me - we did this and it worked out.)

Now assume you inflate your tires to 40/40PSI. That means the contact patch
for the fronts becomes 11.87 square inches, or a 42.5% decrease in the
amount of rubber hitting the road. The numbers for the rear are 22in^2 and
a 25% decrease in rubber contact. Do you really want to be driving on tires
inflate so much you lose a significant amount of traction, stability and
control?

On the flip side, if your tires are under inflated, the contact patch
becomes much bigger, and causes uneven wear on the tire as well as excessive
heat and poorer handling, among other things, I'm sure.

-Hank Eskin #1619