opinions on tire pressure

[clummus]

I am curious about your opinions on optimal tire pressure .. Not the owner manual recommendation. I've read threads that say to increase it for better mpg. I'm not a car person normally and my ex always took care of that stuff.

[jsolan]

Higher pressure gives slightly better mileage because of reduced friction (less rubber on the road).

But it also reduces handling/breaking slightly for the same reason. It can also cause uneven tire wear if the pressure is too high (or too low).

 

I used to run mine somewhere between the manual suggested and max of the tire during the summer. My '06 fusion recommended 33 and my tires had max of 45, so I ran at 36-38. I saw at most a 1 mpg difference. During the winter I would always drop them back down to the recommended for better traction.

 

I haven't played with the pressure at all in my '13 yet.

[hermans]

I run both my hybrids at the factory pressure. I meet and often exceed the EPA ratings for both cars. Some have really pumped up their pressures and I think that spells trouble, as Jsolan stated above.

Edited June 14, 2013 by hermans

[neod192]

I'm running mine at 44 PSI. The ride is rougher, but I get decent mileage. Thinking of going back down to 37 ...

[GrySql]

My tires are the 51psi maximum type, I've settled on a working pressure of 42psi when cold.

[thavil]

My manual for the FE Fusion says 35psi. Took delivery with 40psi but after 2 weeks of rough driving, running mine at 36psi with great results.

[jeff_h]

I ran 40 psi on my 2010 FFH and still had more wear on each of the outside edges than in the center, so it definitely was not overinflated.

 

I've done the same on the 2013 FFH, IMHO the door sticker pressure may make for a smoother ride but causes too much wear on the outside of the tires, which is aside from the minimal MPG gain from the higher psi.

 

I recommend that you do some sampling on your own - if you have predictable trips (like a daily commute) then run a tank or two of gas with a lower pressure, run a tank or two with higher pressure, see what the difference in MPG is (as above, I think higher psi will get you more but the gain is minimal) - and see if you can tell the difference in the ride quality. Or better yet, have someone else adjust the air so you don't know which tank(s) is on which psi and see if you note a difference in ride and MPG, so you are less likely to change your habits to skew any results.

[vangonebuy]

The door jamb sticker noted 34psi as I recall.

Came from the dealer with 44psi..

I left it. Seems fine.

Very Quiet tires, I would add.

[gadgetguy]

When I first got mine I ran the tires at 45 psi and the car drove great (albeit a little rough) and as it got a few miles on it I started getting so good mpg numbers. I drove that way for a good 4000 miles or better and then decided to drop my cold pressure down to 37 and see how it did. The last 3 tanks have now been at 37 psi and I get the same mpg numbers as I had been getting and the ride is much smoother. I will be staying at the 37 mark.

Edited June 17, 2013 by gadgetguy

[acdii]

I have run it at 44 and 34 on the first one, and right now, not a clue what the pressure is at. Been meaning to check them, but 44 seemed to be a good number, even in snow.

 

Best way to find out the exact pressure for even tire wear is to take a piece of chalk and run a heavy line across the tread, then drive the car forward at least two revolutions in a straight line on pavement, and check the wear pattern. If more is rubbed off the center, reduce the pressure, if more is rubbed off the outer edges, increase the pressure. If more is rubbed off one side than the other, get an alignment done. If it takes more pressure than the sidewall to get an even wear, I dont know what you could do.

 

 

Whether or not the even tire wear will also give optimum MPG, I havent really tested it, but the above method is great for getting the most even wear out of your tires, and best overall traction too.

[hybridbear]

Our car came from the factory at 42 PSI all around. I haven't touched the tire pressure. I try to check it monthly and as of the day before our trip all 4 tires still show exactly 42 PSI after over 10,000 miles of driving. The ride has been quite comfortable at 42 PSI. I will rotate the tires when we get home from our road trip and will then look at the wear pattern. By that time we will have close to 16,000 miles on the tires and I should be able to see if they are wearing unevenly, indicating overinflation

[Jamone]

I've been playing around with tire pressure for a while on this car, and I don't see much difference between 36 and 44 psi. At 44 psi I'm averaging around 43 mpg on my daily commute. Down at 36 psi I see 42 mpg. The ride is much better when the pressure is below 40 psi. So I'm currently running 38psi.

[dalesky]

Here's a quote from Tire Rack:

 

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 running over potholes or debris in the road. Higher inflated tires cannot isolate road irregularities well, causing them to ride harsher. However, higher inflation pressures usually provide an improvement in steering response and cornering stability up to a point. This is why participants who use street tires in autocrosses, track events and road races run higher than normal inflation pressures. The pressure must be checked with a quality air gauge as the inflation pressure cannot be accurately estimated through visual inspection.

And from the Rubber Association of Canada:

 

Over-inflation

Over-inflation can be a problem too. An over-inflated tire rides on just the centre portion of the tread. The smaller contact area means reduced grip on the road, leading to a harsh ride, handling issues (such as steering and stopping problems) and increased wear on tires and suspension components.

I inflate all my tires at very close to the door sticker, maybe 1 or 2 lbs over at most.

[hybridbear]

The new thread created by Eddie and link by Jeff_h reminded me that I had previously commented here about checking our tire wear after 16,000+ miles at 42 PSI and then I forgot to come back here and do it. Our FFH is now pushing 18,000 miles. I have not yet had to add air to the tires and all 4 currently show 41 PSI. The wear pattern looks very even. At some point I hope to follow acdii's suggestion above with chalk to see how even they are.

[vangonebuy]

Just checked my tire pressure while up in Rochester, NY.

All 4 tires dropped down to 36 psi from 44psi.

Looks like the cold weather is coming and has a big effect on our low profile tires.

 

My trip home has slightly better mileage. But it also didn't have such a crosswind.