[ryude]

Yup, finally hit 35 MPG today. At the beginning of this tank, I aired tires up from 32 to 40 psi. I was thinking it would make for a harsh ride and such, but it's actually a little smoother and cornering has really improved.

But one thing I didn't expect was the increase in MPG!

32 PSI same trip to/from work @ 60 MPH = 31.90 MPG
40 PSI same trip to/from work @ 60 MPH = 34.97 MPG

Disclaimer: I do not represent forteforums.com, do this at your own risk, yada yada yada.

 

[my forte koup]

I tried that with my koupe sx, and i felt like a was driveing a pick up truck, i felt every ripple in the road, set back to 32 psi and my car was back!!!

 

[ryude]

You have the SX, different tires. Some tires perform better with higher PSI.

 

[Doolie]

My tires came @ 42psi from the dealers, lots of people here have also had this too.

 

[ryude]

Mine came at 32 PSI, because that's what the dealer recommends.

 

[jeff613]

Disclaimer: I do not represent forteforums.com, do this at your own risk, yada yada yada.

Love the Disclaimer!!
Perhaps you should inform your dealer of this mod!

 

[jarret_g]

My tires came @ 42psi from the dealers, lots of people here have also had this too.

That's because your dealer didn't do a proper PDI

 

[hazmat]

mine are at 35 psi and im getting about 33 and its the sx.. love it! may put them to 40 tomorrow morning before i go to work....

 

[Aidensgrand]

i get about 30 if im lucky! i usually avg btw 25-28 but that's cuz i have places to be son and i like hearing my CAI roaring at the other drivers to move the eff over!

but my psi is at about 34

 

[ryude]

Love the Disclaimer!!
Perhaps you should inform your dealer of this mod!

I'm sure they'd get a kick out of it

 

[KiaTech]

Cost of fuel lowered.... ok... but verses the cost of prematurely wearing your tires and buying a new set of those? There's some math here to be done but it's late and my point is that this is a trade off.

 

[caroach]

Doesn't an over inflated tire loose wet weather traction? This isn't a dig at anyone, this is an honest question.

 

[CorsaKoup]

If it's overinflated to the point that most of the car's weight is concentrated on the center-most tread blocks, compromised traction and accelerated tire wear are what you get along with your better gas mileage. Wet grip will be worse as well.

 

[MFury]

I set my Nexen's on my EX to 40 for a month and did get better fuel economy, especially on the highway but I found the ride too harsh for our roads here so I set it back to 32psi which is nice and smooth running now. I do 99% city anyways and rarely travel long distances.

 

[ryude]

Can I just say that the tire manufacturer's max psi rating will get you the best fuel economy, the longest tread life, more even tread wear, BUT you will sacrifice ride quality and a little traction.

There has been no evidence that running a higher tire pressure was the direct cause of what you claim CorsaKoup.

Here are published numbers for Goodyear Tires with a Max Sidewall Inflation Pressure of 35 PSI for vehicles that 'recommend' a pressure below the maximum.

#############################

Dry Macadam Surface
(Stopping Distance in Feet)

2001 Dodge Grand Caravan Sport__20 psi__28 psi__35 psi
Full Depth Tread with ABS_________75.5____76.2____75.8
1/2 Depth Tread with ABS__________69.9____68.1____66.3
Full Depth Tread without ABS______98.3____95.9____91.6

1997 Ford Ranger
Full Depth Tread with ABS_________80.8____78.2____77.6
1/2 Depth Tread with ABS__________79.0____74.8____71.4
Full Depth Tread without ABS______97.8____96.5____94.1

#############################

0.02 Inch Wet Macadam Surface
(Stopping Distance in Feet)

2001 Dodge Grand Caravan Sport__20 psi__28 psi__35 psi
Full Depth Tread with ABS_________79.8____78.5____77.1
1/2 Depth Tread with ABS__________84.7____73.7____81.4
Full Depth Tread without ABS_____111.1___110.2___108.6

1997 Ford Ranger
Full Depth Tread with ABS_________83.8____81.5____79.8
1/2 Depth Tread with ABS__________91.5____89.4____84.6
Full Depth Tread without ABS_____131.9___126.0___118.4

#############################

0.05 Inch Wet Macadam Surface
(Stopping Distance in Feet)

2001 Dodge Grand Caravan Sport__20 psi__28 psi__35 psi
Full Depth Tread with ABS_________80.0____81.1____82.7
1/2 Depth Tread with ABS_________103.7____99.7____92.2
Full Depth Tread without ABS_____118.0___112.2___111.7

1997 Ford Ranger
Full Depth Tread with ABS_________89.7____86.0____81.5
1/2 Depth Tread with ABS_________125.7___118.5___104.5
Full Depth Tread without ABS_____142.9___134.8___125.7

#############################

Picture of a tire with over 35k miles at 50 PSI, if you can see any signs of abnormal tire wear please let me know.

Taken from: http://priuschat.com/forums/gen-ii-...24-integritys-over-35k-miles-50-psi-pics.html

Same tire at the recommended 32 PSI

 

[CorsaKoup]

My sister's Mustang is all the evidence I need of what happens to overinflated tires. All four were bald right down the middle because in her infinite wisdom, she filled them to 50+ for her trip from PA to WY and forgot to let it out when she arrived. A few months later, she found herself replacing them and got some stern advice about tire pressure from the guy at our Firestone store.

 

[ryude]

Now I wouldn't necessarily recommend 50+, but I always go by the max psi rating on the tire's sidewall. If it says 44, I recommend 40. If it says 51, I recommend 45. If you put 32 psi in a tire that has a max psi rating of 44, you WILL see uneven tread wear.

 

[CorsaKoup]

Mine aren't wearing unevenly.

 

[ryude]

How many miles, I bet they start to show uneven wear by 12,000 miles.

 

[CorsaKoup]

5200, haven't even rotated yet.