Theoretically larger rolling diameter will increase highway MPG... the reason is because it changes the ratio of RPMs to tire rotations such that your engine doesn't need to spin as fast to go the same speed.Originally Posted by taylorRichie
You know there are two sides to the tire inflation deal.
1- over inflated / highly inflated = less rolling resistance = better MPG
2- under inflated = smaller rolling diameter = better MPG
"Shifting into 4WD" by Harry Lewellyn make the claim that lower PSI = higher MPG.
Someone should run a test using LT tires. 40 PSI, 35 PSI and 30 PSI.
I'd do it, but I haven't driven my car in almost 4 weeks, so It'd take me a while to go through 3 tanks of gasI'm still on the tank of gas I filled up BEFORE I ran the trail with Todd, and Zeus.
Please keep us posted on your hydrogen findings.
the down side is added weight which means it takes more energy to build momentum (eg: stop and go city traffic mileage would be worse).
Wider tires will suck down your MPG because the more contact area you've got the more rolling resistance exists, especially when turning.
consider that most people running 33s are also running 12.5" wide as well... the wider track and added weight will do more damage than the added diameter will help.
Proper alignment and proper inflation help too.
if you want the best mileage though you're looking at installing some wagon wheels on your VX
seriously though.. I've heard from more than one trooper owner that the 3.5L with factory gearing likes 265/70/R16s the best for MPG... moving to that size over the factory 245s was good for 1-2 MPG (that's a 5-10% increase right there)
By that metric consider that moving to higher octane may increase your mileage by 1-2 MPG would be more than enough to eat the extra cost of the fuel.
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Personally, I'm wondering how much damage the EGR valve is doing...
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