Tires: tire, inflation pressure, fuel savings

Question
I would like to know about lrr?
My question is does running temps of tires affect
the rolling resistance?
I have just purchased Kumho 793 155 80 x13" tires.
Do you know the rolling resistance of these tires?
It seems they are running softer than my invicta gl OEM tire on my car. any info would help thanks..

Jeff @  pro65mustang@hotmail.com

Answer
Jeff,

Since rolling resistance is the result of consuming energy and the output is heat, the running temperature of a tire might be a good way to determine how good the rolling resistance of a tires is.  But there are some factors that would be left out and there is probably an easier way to get directly at rolling resistance.

But inflation pressure plays more of a role in RR than the differences between tires, so the most important thing if fuel savings is your goal is to check your tire pressures.  I recommend 3 to 5 psi above what your vehicle placard says.

And be careful thinking that "soft" tread rubber generates more RR.  Also be careful thinking soft riding tires generate more RR.  It's a ton more complicated than that and some of the best RR tread compounds are fairly soft and ride qualities are more a function of inflation pressure and tire shape.

Lastly, I just don't have enough information about all the possible tires that are on the market, so I won't be able to help you with specific tires.