PSI vs MPG

Has anyone done experiments with higher PSI in their tires, and it's affect on MPG, maybe with data to share?

For example, the tires I have on my Tacoma have a 51 PSI Max rating, which is like 70% higher than Toyota recommends!

Obviously whatever PSI you're at would need to pass the chalk test, so you're not wearing the tires irregularly. And I know the higher the PSI the firmer the ride so there would be some give and take there.

Anyone?

 

Yes higher psi increase a tad bit of your fuel economy but it will cause your tire uneven thread long run.

 

That's what I wonder.... why would my tire be rated at 51 PSI and yet cause uneven tread long run?

And with increasing fuel economy by a bit, what are we talking exactly?

 

The tire can go on many different vehicles, and that PSI rating is simply for the load numbers printed on the tire. Max load at X PSI. Generally speaking, when your tire pressure is increased beyond optimal it reduces the contact patch of your tires---wears in the middle. 51 PSI is pretty high for a light weight vehicle like a Tacoma.

 

51 psi is the maximum allowable pressure, higher pressures may/will affect the tire's structural integrity. Proper working inflation pressure is application dependent and determined by load, road surfaces, handling and ride quality, etc. Manufacturer recommended pressures are determined by their consideration of those factors.

Re: mpg, keep in mind that meeting the CAFE (Corporate Average Fuel Economy) standards is a top concern for automakers; they pay stiff fines when CAFE requirements are not met. I.e. they have no reason to recommend tire pressures--or intake/exhaust systems or engine/transmission tunes--that would significantly reduce fuel economy.

The Dunlop 265/65-17s on my '09 DCSB are each rated for 2337 lbs maximum load--so unless I loaded the truck to 9348 lbs (2337 * 4 or 4000 lbs over the TRUCK'S 5350 lb GVWR) there is no reason to run them at the 51 psi maximum rated pressure.

Somewhat elevated inflation might improve fuel economy a bit, but definitely not all the way to 55 psi...

 

I've found that higher pressures improve my fuel mileage a small, but noticeable (measurable) amount. However, the ride of the truck was negatively impacted and road noise increased quite a bit, and in the long run I think the uneven tire wear will cost me more than the money saved on gas.

 

The mpgs really improve once you wear down to a smooth strip in the middle! You still have tread on the sides for traction when you air down too! Win-win!!!

My tires are max 80psi, but my ideal pressure is around 40. I run 45 on longer trips and during the hot months. I run 35 in the cold months. The rest of the year, I keep them at 40.

 

My OE Dunlops are 51 # tires.
The owners manual wants 30.
I set all 4 at 30 and reset the TPMS there.
I then ran them at 40 for a couple of years.
I noticed a half a mm less tread depth in the middle compared to the edges of the tread.
Therefore I now run them at 36 #.

 

Its not worth it for the small MPG gain.

 

Title made me think this was a boost question. I'm out....

 

This ^

 

Real life? Excessively high PSI will kill you. It has nothing to do with tire blow outs. It has to do with the contact patch. At 51 PSI a Tacoma won't have enough weight to stop the tire from bowing out in the center. That means only a smaller percentage of the tire is touching the road. The less the tire touches the road the less contact there is for things like braking, steering, and not dying.