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Long time lurker, first time poster. I just received my 5-door and was curious what psi others are running in their tires? The Continentals that came with the 17" polished alloys indicate a max of 51psi - currently set at 40psi.

Two-thirds of my commute is highway and I have been averaging ~38mpg although I did manage to squeeze out 51mpg (no stops, 40-50mph for approx. 15 minutes[headbang]).

 

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Long time lurker, first time poster. I just received my 5-door and was curious what psi others are running in their tires? The Continentals that came with the 17" polished alloys indicate a max of 51psi - currently set at 40psi.
You should use the recommended tire pressure (35 PSI) as a guideline.

I usually set the tire pressures to 2~3 PSI greater than the recommended pressure.
 

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A good place to start is what ever the sticker on the door jam recommends. The tire rating is the safe maximum pressure the tire can handle.
 

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I have the 18" summer tires which recommend 39psi. I was wondering if it would be dangerous to drive with about 5psi more than this? Do you think there would be a noticeable difference in gas mileage - especially at lower speeds?
 

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[welcome] to ff.com

as stated above 35 psi is normal

the reading on the sidewall of the tire is the max the tire can handle, however this is set by the manufacture of the tire. The 35psi that ford stated for the car, which gives you the proper footprint where the tire meets the road, this insures proper traction, tire wear, and fuel economy, always set tires at what the car manufacture says, Never set your tires at the max rating on the sidewall.
 

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The 35psi that ford stated for the car, which gives you the proper footprint where the tire meets the road, this insures proper traction, tire wear, and fuel economy, always set tires at what the car manufacture says, Never set your tires at the max rating on the sidewall.
But...but... hypermiling and such? (I've never tried, but I'm tempted to)
 

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I have found having the front tires at 5 to 8 PSI higher than the rear gives the actual equal tire footprint.
The front of a front engine car IS HEAVIER, and thus the tires, to actually have the same footprint oval, fronts have to have higher pressure than the rear.
Also with too much pressure in the rear tires, the ride gets really choppy.

So if you are trying to save gas with higher pressure in the tires...
If the recommended all around is 35, go 37 rear, 42 front. Even 43 front
(A V-6 i would go 8 pounds heavier front than rear, with a small four banger, like the Focus, four to six pounds more air front is great.)
If you want a good ride, then stick to 36 instead of 35 rear, and 40 or 41 front.
I am using 41 front, 36 rear and the ride over concrete is MUCH better than 38 all around.
I may go up to 43 front and 36 rear just to try it out. (When the front steering is very 'light' then your front tires are too high a PSI)
IMO the 'even' all around tire pressure is for simple folk not to get confused. [poke]
(Feel free to dis' me for that comment, no problem, I stick by the reality of actually measuring the contact oval and IF YOU DO, the front PSI will be higher to aquire a similar oval contact patch (the golden ring of tire pressure, read up on it...), as I said, by anywhere from 4 to 8 pounds.. in a front engine car. ALWAYS
[hihi][hihi][hihi] [welcome].
 

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I have found having the front tires at 5 to 8 PSI higher than the rear gives the actual equal tire footprint... Feel free to dis' me for that comment, no problem, I stick by the reality of actually measuring the contact oval and IF YOU DO, the front PSI will be higher to aquire a similar oval contact patch...
Wow - I took a automotive design class last semester and for all of the "contact patch" talk we went over, we never talked about higher pressure in the front tires. But it makes sense to me!
 

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But...but... hypermiling and such? (I've never tried, but I'm tempted to)
true, hypermiling is a different story, in order to do hypermiling you will need to set your tires higher to get the best results. While I will admit a higher set psi will get you better mileage, there are many more factors in how you drive in order to get the same result of higher mpg's. But consider this the higher pressure puts more wear on the middle of the tire, resulting in premature wear. also with less rubber on the road less traction, while this isn't an issue with dry roads, when it rains you have a much higher chance of hydroplaning than if you had your tires set at the recommended setting due to the size of the foot print.

I have found having the front tires at 5 to 8 PSI higher than the rear gives the actual equal tire footprint.
The front of a front engine car IS HEAVIER, and thus the tires, to actually have the same footprint oval, fronts have to have higher pressure than the rear.
Also with too much pressure in the rear tires, the ride gets really choppy.

So if you are trying to save gas with higher pressure in the tires...
If the recommended all around is 35, go 37 rear, 42 front. Even 43 front
(A V-6 i would go 8 pounds heavier front than rear, with a small four banger, like the Focus, four to six pounds more air front is great.)
If you want a good ride, then stick to 36 instead of 35 rear, and 40 or 41 front.
I am using 41 front, 36 rear and the ride over concrete is MUCH better than 38 all around.
I may go up to 43 front and 36 rear just to try it out. (When the front steering is very 'light' then your front tires are too high a PSI)
IMO the 'even' all around tire pressure is for simple folk not to get confused. [poke]
(Feel free to dis' me for that comment, no problem, I stick by the reality of actually measuring the contact oval and IF YOU DO, the front PSI will be higher to aquire a similar oval contact patch (the golden ring of tire pressure, read up on it...), as I said, by anywhere from 4 to 8 pounds.. in a front engine car. ALWAYS
[hihi][hihi][hihi] [welcome].
You make a very valid argument here. and while I do agree with most of what you have said, and it is true that a higher will result in a better ride typically, but once again your making a smaller footprint with the road. Yes there is more weight up front, and yes it has a larger foot print due to the weight, but going again back to traction, since the car is front wheel drive you will get more traction, and the majority of the breaking is done with the front breaks as well. So with a higher pressure up front making the foot print smaller, it could affect traction negatively, and increase breaking distances.
 

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Keep in mind the recommended pressure is with the tires cold. Driving the car with the tires flexing raises the temperature and increases the pressure. In hot weather the tire pressure can go much higher than the recommended pressure. Also, if the tires are too hard (over inflated) they are prone to damage from rough roads, curb and junk on the street.
 

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Keep in mind the recommended pressure is with the tires cold. Driving the car with the tires flexing raises the temperature and increases the pressure. In hot weather the tire pressure can go much higher than the recommended pressure. Also, if the tires are too hard (over inflated) they are prone to damage from rough roads, curb and junk on the street.

I have to disagree. Hard tires are way LESS likely to be damaged than underinflated.
And even hard vs standard inflation i would still bet the hard tire (as long as the cold inflation pressure does not exceed the tire's rated pressure) will suffer LESS damage. and bet money on it. (the tire in use pressure/temp does not matter if the cold inflation pressure is under the rated one)
The cars suspension might not fair so well for a really big pothole with really firm tires, but the tire? no way will it be damaged.
 

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I have to disagree. Hard tires are way LESS likely to be damaged than underinflated.
And even hard vs standard inflation i would still bet the hard tire (as long as the cold inflation pressure does not exceed the tire's rated pressure) will suffer LESS damage. and bet money on it. (the tire in use pressure/temp does not matter if the cold inflation pressure is under the rated one)
The cars suspension might not fair so well for a really big pothole with really firm tires, but the tire? no way will it be damaged.
It always amazes me that people think they know more than the actual engineers/designers/manufacturers when it comes to their vehicles. The tire pressure postings on the vehicles sticker are there for a reason, I'm sure it's not an arbitrary number pulled out of the "air", excuse the pun. IMO.
 

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It always amazes me that people think they know more than the actual engineers/designers/manufacturers when it comes to their vehicles. The tire pressure postings on the vehicles sticker are there for a reason, I'm sure it's not an arbitrary number pulled out of the "air", excuse the pun. IMO.
I agree.
Asking a question about tire pressure is like asking a question about oil, too many opinions to get a good answer. With that said, here's my opinion. As stated above, people much smarter than me determine what the best pressure should be for the weight, suspension and driving characteristics of the vehicle. I keep a close watch on my pressure because of temperature variations (the temp dropped 30 degrees here in 5 days). I checked mine yesterday and added 3 pounds all around. I keep mine at the recommended 35 psi because of the reasons above and because I'm worried that if I'm ever in a collision where there the tires were a factor, I want to be at the recommended pressure so some slick lawyer can't shift fault or negligence to me. I know it was a while ago, but after the Firestone incident, Ford, or any auto or tire manufacturer isn't going to take blame for a tire or wheel failure without doing a thorough investigation. This may sound a little paranoid, but if something "they" built and not my negligence was the cause, I want to be covered.
 

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The engineers got it right...period...well except for that time with the Explorers and Firestones (which was the fault of both companies (28psi? Really?)). Just keep the recommended pressure in your tires TO KEEP YOU AND EVERYBODY AROUND YOU SAFE. You're giving up traction by adding more and risk rolling the tire iff the bead with too little.
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I run my tires about 5 psi higher front and rear to squeeze out a few more MPG's - on my 08' (I know, wrong section) I gained 2-3mpg with a drop in K&N and the tire pressure increase.
 

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I run my tires about 5 psi higher front and rear to squeeze out a few more MPG's - on my 08' (I know, wrong section) I gained 2-3mpg with a drop in K&N and the tire pressure increase.
2 or 3 mpg is actually a pretty good gain, 5-10%?
 

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The recommended pressure is an average pressure for average driving.
If you do average driving and want to have no problems and no concerns, then YES OF COURSE run the pressure recommended.
If you want any other considerations to apply, then you will be on yor own.
Fo those interested, i gave my opinions and experiences.
The people who worry about it do NOT need to do anothing different. period.
For those interested, then they can re-read my comments to good advantage.
The ones who want to not think for themselves, please do not even READ my stuff.
no problem. [woot]
 

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It always amazes me that people think they know more than the actual engineers/designers/manufacturers when it comes to their vehicles. The tire pressure postings on the vehicles sticker are there for a reason, I'm sure it's not an arbitrary number pulled out of the "air", excuse the pun. IMO.
Agreed! I run 35psi, which is what's recommended. I would think that over-inflated tires would affect grip, handling, braking and tire wear. Not going to second-guess the engineers...
 

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It always amazes me that people think they know more than the actual engineers/designers/manufacturers when it comes to their vehicles. The tire pressure postings on the vehicles sticker are there for a reason, I'm sure it's not an arbitrary number pulled out of the "air", excuse the pun. IMO.
The manufactures recommendation is a compromise based on all the different things people have said. You are free to change the compromises the engineers made and it has nothing to do with thinking you know more than they do.

I have been an engineer for more than 30 years and I rarely use a product at the recommendations I have contributed to in the user documentation. I have my own set of compromises that I am willing to make and do just that with everything I use. Sometimes that matches the documentation sometimes it doesn't.

A lot what goes into user documentation is to protect the company from liability if misused and is written to the intelligence of the lowest expected user.
 
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