I just purchased my TCH about 2 months ago and am loving it. Lately I noticed the mpg rating has decreased so I came here to find out what others are getting. After reading probable causes I figured to check the tire pressure. Sure enough mine were at 26psi. The door recommends 32psi, others on this board recommend 40 or a little more but my Bridgestones says "max psi 51lbs". What is the real consesus here?

Thanks
Ric

 

Great question. I am also in the same situation. I just recently up'd my tire pressure to 45lbs. So far I don't see any changes however I am only about a quarter of a tank into this. I will post what I find out. But anyone with some experienced input would be helpful!!

 

Go as high with tire pressure as you feel comfortable with. It helps a lot from say 32 to 45 or so. After that the benefit kind of slows down. I recomend max sidewall.

 

The "consensus" is don't go over the sidewall rating, but you can approach it to improve MPG. If the door panel suggests different Front/Rear PSI, maintain the difference when you run higher PSI overall.

Most of those that run 42/40 (including me) have a sidewall rating of 44 PSI max pressure on their tires.

JeffD

 

http://www.tirerack.com/tires/tirete...currentpage=38

Disadvantages of Overinflation

An overinflated tire is stiff and unyielding and the size of its footprint in contact with the road is reduced. If a vehicle's tires are overinflated by 6 psi, they could be damaged more easily when encountering potholes or debris in the road, as well as experience irregular tread wear. Higher inflated tires cannot isolate road irregularities as well causing the vehicle to ride harsher and transmit more noise into its interior. However, higher inflation pressures reduce rolling resistance slightly and typically provide a slight improvement in steering response and cornering stability. This is why participants who use street tires in autocrosses, track events and road races run higher than normal inflation pressures.


Disadvantages of Underinflation

An underinflated tire can't maintain its shape and becomes flatter than intended while in contact with the road. If a vehicle's tires are underinflated by only 6 psi it could weaken the tire's internal structure and eventually lead to tire failure. Lower inflation pressures will allow more deflection as the tire rolls. This will build up more internal heat, increase rolling resistance (causing a reduction in fuel economy of up to 5%) and reduce the tire's tread life by as much as 25% while increasing the probability of irregular treadwear. Drivers would also find a noteworthy loss of steering precision and cornering stability. While 6 psi doesn't seem excessively low, it typically represents about 20% of a passenger car tire's recommended pressure.

 

Do a search on "tire pressure" on this website. There are EXTENSIVE discussions available for perusal.

 

You may as well head to Washington and look for a consensus among politicians. More of a chance of that happening. Personally, I upped mine from 32 to 40 psi. Can't say as I see much of a change.

 

I run the Bridestones and Continentials on my HCH and FEH at sidewall max.

I think that almost everyone will agree that the 26 psi they were at on your car was far too low.

As cooler weather rolls around, you will find that the cold pressure in the tires will reduce by about 1 psi per 10 degrees. So, if a normal low in your area is about 65-70 in the summer, and is now at 45-50, you may see the tires at 2+ psi below what you saw it in the middle of the summer.

Good luck!

 

I guess the unasked questions are "why did the tire pressure drop to 26psi?" and "why didn't that drop trip the low tire pressure sensors?"

 

My guess is that the dealership of factory set it to 26 psi. The TPMS would not indicate a fault as that was the pressure it was calibrated to.