Best tire pressure for Fuel Economy

[edmscan]

I was wondering what tire pressure I should use on my 2007 Yaris RS LB. I have Goodyear Assurance tires which have a maximum pressure rating of 51 psi. On my door jam .. it says to set tire pressure at 32 psi. I have set my tires to 40 psi as I felt that is someplace in the middle.

I am interested in getting as much fuel economy as I can without damaging my tires.

Is there an optimum amount of pressure to use for good fuel economy ?

[TLyttle]

I'm led to believe that the max pressure is for setting the bead, then dump them down to 32 as per the label. However, the label pressure has to do with handling.... and RIDE. If, like me, you don't give a damn about ride, then take them up into the 40+ range. Anything over that, and grip begins to deteriorate. Lots of the hyper-miler guys run at 60+, but my experience has been that the tires tend to skate at that pressure.

Just my opinion...

[tooter]

I always run tires at their stated maximum pressure, usually 46 pounds.

[Hershey]

35 >37 . '08 Yaris sedan with the 4 speed auto has overall gas mileage close to 38 for nearly 4 years . Was bought new in mid May of '08 .

[nopk]

you have to ask yourself: do you want to spend more money on tires, or more money on gas?

it's like this: if you set your PSI higher than recommended, you're going to rub away the rubber away quicker, and in a more detrimental way - and end up having to replace the tires more often. sure, you may get better MPG, but at the cost of possibly unsafe handling characteristics and spending way more on tires.

if toyota says 35psi, put it at 35psi. they don't employ thousands of engineers to just "guess" 35psi, they've done the work to make sure that it's most efficient and beneficial to you

obviously, i mean this for daily driving. if you're autocrossing you're going to want to use different pressures for whatever reasons you'll find

[Hershey]

Try to keep tires at about 37 during late fall > mid spring due to variations of pressure in cold / warm temps . 35 or a bit more for warmer months . Molecules are a bit of a nuisance . May have try nitrogen for more constant pressure .

[edmscan]

Thank you for those that replied. I will see how my car seems to feel at 40 psi for a while .. and see if running them at 32 like Toyota recommends feels any different.

[TLyttle]

Have a look in your Moaners Annual, nopk: extra pressure is recommended under some conditions. Maybe not as much as I suggest (up to 40+), but certainly an extra few pounds for high-speed cruising. In fact, I find that my tires wear less at higher pressures, plus the better mileage yielded. My OEM tires wore at a horrendous rate before I bumped the pressure up, but by then the damage was done. AND the bite was better.

As mentioned before, much of the recommended pressures by "thousands of engineers" compromises "ride' into the equation. There is no logical way to determine "ride" as it is always subjective: 1,000 engineers, 1,000 opinions on ride. Besides, changing tire make or wheel size pitches the calculations right out the window.

[daf62757]

Just wondering if you can buy your nitrogen and do it yourself. Most shops won't over inflate with nitrogen.

[mazilla]

Have a look in your Moaners Annual, nopk: extra pressure is recommended under some conditions. Maybe not as much as I suggest (up to 40+), but certainly an extra few pounds for high-speed cruising. In fact, I find that my tires wear less at higher pressures, plus the better mileage yielded. My OEM tires wore at a horrendous rate before I bumped the pressure up, but by then the damage was done. AND the bite was better.

As mentioned before, much of the recommended pressures by "thousands of engineers" compromises "ride' into the equation. There is no logical way to determine "ride" as it is always subjective: 1,000 engineers, 1,000 opinions on ride. Besides, changing tire make or wheel size pitches the calculations right out the window.

There is more to consider than ride quality, contact surface and traction are more important. It has alwas been my stance that extreme over-inflation is a hazard to the driver and the public forced to be around them.

Last time i brought up the safety side f it the hyper-milers got a little butt hurt...

[nookandcrannycar]

I can't imagine either extreme, and 60 + PSI just seems insane. I've tried the max PSI on my tires (44 I think with each set I've purchased) and even that makes me feel as though I'm driving with bricks instead of tires. On the other end, I've gotten my car back from an oil change with the PSI changed to the spec on the tire (not my request) and I feel as though I'm floating on the high seas and have less control than at a higher PSI. I keep my tires at 38-40 PSI and can tell If it goes below 38..and that only happened earlier on this current set of tires when I had a slow leak and procrastinated on researching which Firestone shop would honor the specific warranty I have (only factory owned stores honor the warranty at all) and actually got it repaired at Discount Tire for free after a Discount Tire employee spotted me checking my tires in a wide open part of the parking lot at my local Kroger Signature. I carry a tire gauge in my Yaris and behind the rear seat/under the deck lid and hatch I carry a 12v air compressor that I paid about $12.00 for so I can put in my own free air at any time/in any spot. I got almost 10 percent over the mileage rating on my original set and first replacement set of tires and will get much more than that on my current set. I eyeballed my overall combined MPG, and this is over nearly 217,000 miles -- it's about 40 or slightly higher (I have the individual tank stats, but have never kept a running total). The only negative 'car consequence' that I think about in any significant way is that I might need wheel bearings sooner than if I wasn't running the higher PSI. My worst two tanks MPG wise have not been city tanks but instead on the 80 MPH limit stretch of I-10 in Texas and both in EXTREMELY windy conditions along that stretch. I have run across some idiot drivers whose actions have resulted in my brakes and steering being taxed quite a bit, but it those situations my car feels as though it is almost 'stopping on a dime' (so to speak). I wonder if the NTHSA or any insurance institutes have done any studies related to passenger car tire PSI in any meaningful way that would be useful to Yaris owners.

[RikBakke]

I like to run 2-4 PSI higher (RE92's) than the door jamb sticker recommendations. Decent ride and decent treadwear patterns. For a nitrogen fill, I generally use a mixture with 78-79% nitrogen. This fill mixture has the same pressure vs temp properties as pure nitrogen. I find this is the most cost effective and I get the same pressure variations as a 98% dry nitrogen fill.

When the RE92's wear down, I'll pick up a set of Michelins with the savings.

[vincentg]

is nitrogen better than just air? it gives out more handling but i dont know if it really changes the car's fuel efficiency

[why?]

is nitrogen better than just air? it gives out more handling but i dont know if it really changes the car's fuel efficiency

not sure if anyone really knows for sure if nitrogen does anything, but it is lighter than air, so it might.

[tooter]

Did you know that the air we breathe is 78% nitrogen?

... can't be lighter than air if it is air. :wink:

[why?]

Did you know that the air we breathe is 78% nitrogen?

... can't be lighter than air if it is air. :wink:

it is only 78% of air. check a periodic table though. Argon, Oxygen, Water Vapor, carbon dioxide, etc, is all heavier. So basically everything you find in our environment will be heavier that straight nitrogen.

Getting all the facts right is better than making snide comments.

[tooter]

Lighten up, W...

(oooh... a pun :wink:)

Nitrogen being "lighter than air" just struck me as funny because at 78%, most of air is nitrogen.

[DMZ]

Pure nitrogen is good for tires because there is no moisture in it and it does not migrate through the tire and bead as O tends to do.

The big caveat is cost. $20-$30 per tire. Think I will stay with free atmospheric for now.

[tooter]

That's pricey. I'm with you, I'll stick with free mostly nitrogen, too. :wink:

[sickpuppy1]

is nitrogen better than just air? it gives out more handling but i dont know if it really changes the car's fuel efficiency

The advantages of nitrogen are, its dry, no rust to wheels or sensors or permeation into the tires. But considering most wheels outlast the car, I don't think that's a big deal. The main advantage is its consistent. Air expands when it gets hot so if you set your tires to 40 and drive a long trip, they may end up at 44 psi. Nitrogen does not do that. you set them at 40 and it stays at 40.

[edmscan]

I just got new tires on my Yaris .. and I am interested to see how my mileage changes. I am a little scared that my mileage will decrease now that I have new tires on my car. I got Hankook Optimo 4S "All Weather" tires now (only available in Canada I understand). I am running them at about 34 psi ... which I think is normal.

It will be interesting to see if my mileage has changed ... I will know in less than a week probably.

BTW .. I opted not to go with Nitrogen as I think that normal air will do me just fine.

[Yar Is Word]

I I got Hankook Optimo 4S "All Weather" tires now.

I have Hankook Optimo 727s. They seem to be better handling than OEM tires, especially in rain and snow, but cost 1-2 mpg.

[edmscan]

So far I have no issues with my new Hankook tires. They seem to be just fine .. they are quiet and seem to work well in most conditions. I have yet to try them in snow .. but from what I have seen on YouTube, they should perform well. I have actually also gained 2 MPG since changing tires, so overall I am quite happy.

[2012YarisSE]

is nitrogen better than just air? it gives out more handling but i dont know if it really changes the car's fuel efficiency
From what I've read on it, nitrogen is a dry gas and thus no moisture will be present inside the tire. Also pressure variances due to temperatures are pretty much non existent compared to air. Nitrogen molecules are larger than air so tires stay inflated longer meaning less top offs. Downside is its expensive to replace air with nitrogen.

[2012YarisSE]

I was wondering what tire pressure I should use on my 2007 Yaris RS LB. I have Goodyear Assurance tires which have a maximum pressure rating of 51 psi. On my door jam .. it says to set tire pressure at 32 psi. I have set my tires to 40 psi as I felt that is someplace in the middle.

I am interested in getting as much fuel economy as I can without damaging my tires.

Is there an optimum amount of pressure to use for good fuel economy ?
The door sticker on my 2012 Yaris says 32 front and 29 rear. however the max psi on the sidewall of the tires says 51 psi. I am running 90% of max pressure or 46 psi. Just started this a couple days ago and will monitor tire wear and if it looks like wear is uneven will back off pressure gradually until wear evens out. However I don't think I'll have to reduce any. I must say the ride is noticably different at the higher pressure. The car rolls and coasts so much better and the inboard real time computer confirms my mileage is better then before. Do notice the bumps more but nothing extreme. I am under the impression the manufacture recommended pressure of 32/29 is a number that accounts for ride quality.

[Idahotom]

That seems to be the general consensus here. I run the max psi listed on the tires I have, 44. I also drive a Dodge 1 ton (85 psi) and a 40,000 lb boom truck (110 psi) and just got a winter driver, a 2000 Toyota Rav 4 AWD (40 psi) all the max listed on the tires. I too notice a marked ease of movement, by hand, one finger almost!

[DJYojimbo]

i'm going on a road trip from chicago to orlando so 32 in the front and 29 in the rear for cold tire pressures is good?