Comfort vs MPG with our Newell Coach

[Newellin Thunder]

How much difference does tire inflation make for MPG? I am running 90 PSI front and 80 PSI rears, I had been running them at the maximum. Am I killing my MPG by lowering the PSI?

[Newell Attack]

Over-inflated steer tires have been known to contribute to wandering.

Proper contact patch is pretty important for lateral traction in the rain.

Pounding the crap out of the coach suspension and frame with harder tires might have some issues down the road.

Adjusting one's driving style and terminal velocity are the surest way of moderating fuel use.

Stop putting the pedal all the way to the floor.

Best to count anything over 5 mpg as a bonus and be done with it?

happy coaching!

[The Newell]

Generally, the higher the tire pressure, the better the fuel mileage. In addition to ride comfort, you will also be sacrificing safety by running your tires over the recommended pressure, and the tires will also wear out faster.

The safety aspect comes from the fact that there is less rubber in contact with the road. That means increased braking distance on all surfaces, and also less cornering traction in emergency handling situations.

The tire wear has to do with the fact that the smaller contact patch will mean the center of the tread will wear faster than normal, and the shoulders will wear more slowly. The uneven wear will get you to sub-legal tread in the center in fewer miles. For many this is a red herring, because the tires need to be replaced from age (7 years maximum, generally) long before the tread wears down. (We would generally wear our tires out every four years, give or take.) It becomes very difficult to calculate whether the improved mileage offsets the increased tire wear in lifetime cost-of-operation; obviously, the more expensive fuel is, the more lopsided the equation gets.

Personally, I would not trade the safety off for minor fuel savings

[NewellCrazy]

[h=2]

Properly Inflated Tires

• Properly inflated tires will give the most efficient gas mileage. Tires that are properly inflated to the manufacturer's specifications can improve gas mileage by as much as 3 percent over driving with improperly inflated tires.
  
  

Too Little Tire Pressure[/h]

• A vehicles gas mileage decreases by 4 percent for every pound of recommended air pressure that is not in the tire. As the tire pressure decreases in a tire, the tire hugs the pavement more and therefore causes the tires to rotate slower and the car to use more gas.
  
  

[h=2]Too Much Tire Pressure[/h]

• If tires have too much air pressure in them, they will not hug the ground very well and this will make it difficult to handle the vehicle in a safe manner. Although over-inflated tires may increase gas mileage by one percent over the manufacturer's recommendations, the decrease in safe handling of the vehicle can be detrimental to the driver and any passengers.
  
  

[pairodice]

Originally Posted by NewellCrazy

Too Little Tire Pressure

• A vehicles gas mileage decreases by 4 percent for every pound of recommended air pressure that is not in the tire. As the tire pressure decreases in a tire, the tire hugs the pavement more and therefore causes the tires to rotate slower and the car to use more gas.

That makes sense, if my tire should be at 100psi and I run it at 25psi I probably won't go very far, hence I would get close to 0mpg... or maybe not...