Tire Pressure for Best MPG? What's your tire pressure ..

Post by **ayap888** » Sun Nov 08, 2009 8:10 am

What tire pressure gets you the best MPG ? What kind of difference have you observed .. let's say going from 30-32 psi to 35-38 psi ?

Post by **RioD007** » Sun Nov 08, 2009 8:23 am

ayap888 wrote:What tire pressure gets you the best MPG ? What kind of difference have you observed ... let's say going from 30-32 psi to 35-38 psi ?

With the way I drive i'm lucky to see 15 MPG... But I ALWAYS run 36-38 PSI cold (greatly improves the cars handling as well as lowering my rolling resistance...

One would assume that running 36-38 cold would help you if you're trying to achieve better fuel economy.

Other steps you could take:

Always use manual mode and short shift to the point that your in 5th then click in into drive to activate the cars overdrive only accessible in the cars D Drive mode not manual or SD mode.

Swap your cars air filters out for K&N units ( sounds MUCH better and gives your a slight boost in performance and fuel economy)

Take out the spare tire tools and all your floor mats.

Drive like a wimp.

But hey whats a few mpg spent for the sheer plesure of driving a truly amazing car thats made to be driven... its not a Honda Civic Eh?

Post by **Timmbo** » Sun Nov 08, 2009 5:10 pm

I would stongly suggest simply keeping your tire pressure at the suggested cold PSI listed on the inside of your door. That will give you the best MPG. Some say filling with Nitrogen will help, but I think the jury may still be out on that one.

Post by **wolf1** » Mon Nov 09, 2009 1:42 pm

My tires are at 40psi and I am averaging overall 24.6.

Post by **ayap888** » Mon Nov 09, 2009 5:07 pm

wolf1 wrote:My tires are at 40psi and I am averaging overall 24.6.

40psi ... hmmm ... I should try that.

Post by **Timmbo** » Mon Nov 09, 2009 6:03 pm

40psi seems high, just keep in mind your TPMS might go off because of it.

Post by **ramprun** » Mon Nov 09, 2009 7:09 pm

Timmbo wrote:40psi seems high, just keep in mind your TPMS might go off because of it.

it will only go off if the pressure of tires are low.

Post by **majorg** » Tue Nov 10, 2009 7:11 am

Running tire pressures very high will drastically reduce tire contact patch. This will adversely affect your braking ability. Unless you drive your car on the track and concerned about tire coming off the rim, it's best to use manufacturer suggested air pressures.

Post by **wolf1** » Tue Nov 10, 2009 2:58 pm

40 psi is what the dealership set them at. I typically run my tires on any vehicle at the highest psi recommended anyway so I left them at that. I think the tires say 40 also.

Post by **majorg** » Thu Nov 12, 2009 4:13 am

Air pressure should be set based on the vehicle, not on the tires. You can find recommened pressures on the driver's door jamb, and, I believe, it says 32-33 psi (cold). The psi rating on the tire indicates maximum safe pressure for this particular tire. If you're running cold pressures that high you are risking blowouts. Even on the track (I track 911, I know) you should try to avoid running air pressures that high. In short, risking blowouts and reducing contact patch and, therefore, available traction, isn't worth saving a little fuel, in my humble opinion.

Post by **mandelbloom** » Thu Nov 12, 2009 4:19 am

Just got my EX and it seemed to be riding a little rough. Checked the cold pressure, dealer had it at 45!! Yikes, I lowered it to 35 all around.

Post by **ayap888** » Fri Nov 13, 2009 2:09 pm

majorg wrote:Air pressure should be set based on the vehicle, not on the tires. You can find recommened pressures on the driver's door jamb, and, I believe, it says 32-33 psi (cold). The psi rating on the tire indicates maximum safe pressure for this particular tire. If you're running cold pressures that high you are risking blowouts. Even on the track (I track 911, I know) you should try to avoid running air pressures that high. In short, risking blowouts and reducing contact patch and, therefore, available traction, isn't worth saving a little fuel, in my humble opinion.

I've driven my Audi at 39-40 psi, where as the ordinary tire pressure was suppose to be 33. I've done it for 50,000 miles and going more than 100+ MPH. It prolonged my tire life to 48,000 miles. And my Audi tire rating was at 130 MPH. I've had 2 Audi's and have over-inflated above the manufacturer's recommendation for 8 years and for over 100,000 miles - no blow out at 120 MPH or more.

The EX35 tire rating has a higher speed rating (163 MPH or more). The manufacturer's tire pressure rating is an 'average' and not a maximum setting. If you know cars, you should the know that that's industry standard practice for ALL car manufacturers. So you can definitely inflated it a few more PSIs.

You are very wrong about the tire pressure being dependent on the vehicle. All tires have a pressure limit, irregardless of the vehicle you're driving. One vehicle maybe heavier than the other, but the tire pressure is still the same pressure whether you set it at 33 or 35 psi. It's like you're saying that a bigger stone will fall faster than a smaller stone fall down - Wrong! gravity is the same.

Post by **majorg** » Fri Nov 13, 2009 4:11 pm

Boy, you mixed it all up! I've never said that you will get a blowout if you inflate higher than recommended. I said you're risking it. Next, please spare me your physics lesson. I have MS in Mechanical Engineering and don't need your amateurish statements. Speed rating of the tire is one thing, it doesn't depend on the type of car. The inflation pressure is entirely different thing: it is strictly vehicle dependent. For instance, I run Pilot Sports on my C2S, the fronts at 30psi, the rears at 37psi (Porsche recommended). When I go to track I increase pressure to 33/40 (cold). This is done mainly to keep tire on the rim, what you may gain in reducing rolling resistance you'll lose in traction. I personally happen to like more traction. The same Pilot Sports on a different vehicle will have totally different recommended inflation pressures. Sames goes for Dunlops on your Infiniti. As for gravity, you're completely wrong. I am not even sure what you meant with your bigger and smaller stone example. Are you comparing speed with pressure? You must be very confused. Higher inflation pressure = smaller contact patch. Many vehicles (not sure about Infiniti) specify higher tire pressures for loaded vehicles (4 passengers vs. 2). By the way, "irregardless" is not a word.

Post by **ramprun** » Fri Nov 13, 2009 7:35 pm

I agree with your statement and i have master degree in chemistry

Post by **Jason Tucker** » Tue Nov 24, 2009 10:18 am

majorg wrote:Air pressure should be set based on the vehicle, not on the tires. You can find recommened pressures on the driver's door jamb, and, I believe, it says 32-33 psi (cold). The psi rating on the tire indicates maximum safe pressure for this particular tire. If you're running cold pressures that high you are risking blowouts. Even on the track (I track 911, I know) you should try to avoid running air pressures that high. In short, risking blowouts and reducing contact patch and, therefore, available traction, isn't worth saving a little fuel, in my humble opinion.

I usually go with another tire than the OE it came with upon the first replacement. Now what good does the door jamb sticker do you? Talk to the "tire guy" that sells you the tire about what's the right range...it's never A number. If the "tire guy" is clueless...you need to see what the mfg. of the tire says.

Post by **squiggyacfd** » Tue Nov 24, 2009 3:35 pm

Tire pressure IS dependent on the vehicle. Like it was said before, the same tire on another vehicle will have a different recommended psi. The pressure on the door jamb was tested to give you the safest, most comfortable, and the best performance of that factory tire for everyday driving. If you were supposed to follow what is written on the tire.....then what would be the point of that sticker?

Post by **Jason Tucker** » Wed Nov 25, 2009 9:25 am

Disagree

Post by **hrlydv** » Thu Nov 26, 2009 5:58 pm

According to tire manufacturer reps that I have talked to, the optimum pressure is one that when the tire is hot, the pressure is 10% higher than when cold. For my EX with the original tires, I run 40 psi cold and when they are hot they are 44 psi. The maximum cold pressure on the sidewall of the tires is 42 psi. I get 24-25MPG on my 2008 EX Journey AWD with ALL options.

Post by **BrokenTiller** » Thu Nov 26, 2009 6:22 pm

-and you have reduced the intended traction of your tires as well.

Post by **hrlydv** » Fri Nov 27, 2009 5:50 am

Actually, I haven't reduced the traction at all. When a tire pressure is too low, the tire flexes more and the internal pressure heats up more and goes up drastically. And yes, the higher the internal pressure the less traction you have. That's why you adjust the pressure to limit the pressure build-up to 10% to maintain the most consistent tire pressure, therefore the best handling and wear.

Post by **ramprun** » Fri Nov 27, 2009 6:00 am

we should get mythbuster to test this

Post by **AWGD8** » Sat Nov 28, 2009 1:20 pm

All I know is step on the gas and those tires roll! regardless of the price of gas at the pump...

And I have an MS degree in ECONOMICS....

Tire Pressure for Best MPG? What's your tire pressure ..

Tire Pressure for Best MPG? What's your tire pressure ..

Re: Tire Pressure for Best MPG? What's your tire pressure .. (ayap888)

Re: (Timmbo)

Re: (wolf1)

Re: (Timmbo)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (ayap888)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (majorg)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (wolf1)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (majorg)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (majorg)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (ayap888)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (majorg)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (majorg)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (Jason Tucker)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (squiggyacfd)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (Jason Tucker)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (hrlydv)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (BrokenTiller)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (hrlydv)

Re: Tire Pressure for Best MPG? What's your tire pressure .. (ramprun)

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