Quote:
Originally Posted by Big Dave
I have been running 100 psi in my E-rated tires (sidewall pressure = 80 psi) in warm weather and cold. No "crowning" is visible and the wear seems even across the tread.
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Hey Dave,
I'm also driving an F350, except that mine's a crew cab, long bed, automatic transmission, 4x4 with 4.10 gears. Totally stock, I was getting <12 mpg city, and ~13.8 hwy. Changing my driving style has now got me >17 mpg city, and >23 hwy, still stock, but with higher tire pressures.
I was running my tires at 80psi for a while, then tried some testing using the Scan Gauge. I ran a few miles of a section of a road with the cruise control set, noted the mpg, then ran it again with the tire pressure at 70psi, then again at 60psi, etc. Strangely, the fuel mileage got better and better as the tire pressure was reduced. Then I realized that the lower pressures were allowing the tires to "squish" more, reducing the rolling radius of the tire (the truck weighs just over 8,000 lbs full of a fuel and me). With lower tire pressures, the odometer was indicating that I had driven farther than when the pressure was at 80psi. =) Not a good test. I'm now searching for an appropriate hill to do a "coast-down" rolling resistance test instead and will determine rolling resistances by the distance the truck rolls at different tire pressures.
My question for you is if you've done similar testing, and found measurable/repeatable benefit going above 80psi, or if you just assumed that higher pressure = lower rolling resistance?
Also, thanks for all your posts. Your successes were instrumental in encouraging me to try to get better mileage with this beast.