How do I maximize Highway MPG?

[Kelleytoons]

Sorry just can't help this (from "Fear and Loathing in Las Vegas - 1973"):

 

At first I thought it was only because the tires were soft, so I took it into the Texaco station next to the Flamingo and had the tires pumped up to fifty pounds each—which alarmed the attendant, until I explained that these were “experimental” tires.

 

But fifty pounds each didn’t help the cornering, so I went back a few hours later and told him I wanted to try seventy-five. He shook his head nervously. “Not me,” he said, handing me the air hose. “Here. They’re your tires. You do it.”

 

“What’s wrong?” I asked. “You think they can’t take seventy-five?”

 

He nodded, moving away as I stooped to deal with the left front. “You’re damn right,” he said. “Those tires want twenty-eight in the front and thirty-two in the rear. Hell, fifty’s dangerous, but seventy-five is crazy. They’ll explode!”

 

I shook my head and kept filling the left front. “I told you,” I said. Sandoz laboratories designed these tires. They’re special. I could load them up to a hundred.

 

“God almighty!” he groaned. “Don’t do that here.”

 

“Not today,” I replied. “I want to see how they corner with seventy-five.”

 

He chuckled. “You won’t even get to the corner, Mister.”

 

“We’ll see,” I said, moving around to the rear with the air-hose. In truth, I was nervous. The two front ones were tighter than snare drums; they felt like teak wood when I tapped on them with the rod. But what the hell? I thought. If they explode, so what? It’s not often that a man gets a chance to run terminal experiments on a virgin Cadillac and four brand-new $80 tires. For all I knew, the thing might start cornering like a Lotus Elan. 

[SnowStorm]

Be careful buying replacements as there are two versions of Energy Saver A/S tires.  The 93V is OEM with the 51 psi rating but there is also a 94V with only a 44 psi rating.  No idea why.

 

Today it seems almost all abnormal wear is from misalignment or failure to rotate (cupping).

[SnowStorm]

.... but seventy-five is crazy. They’ll explode!”

Years ago I was filling up when there was a very loud "pow".  I looked around towards the air pump just in time to see the hose hit the ground - thrown down disgustedly by the poor angry chap who had just "blown up" his tire.  I guess the cornering wasn't good enough.... :lol: or, most likely, there wasn't any gauge on the pump.

 

Gone are the "easy days" where you would turn the little crank until the correct value appears in the "digital display", pump up the tire, ding - ding - ding - - - ding -  -  -  -  - ding  -  -  -  -  - was that the last one?  Shucks, pumping up your tires was kinda fun! :play:

[scottwood2]

Absolutely correct.  The maximum rated tire pressure is there for a reason--safety.  I wouldn't go higher than 44 psi on the Michelin eco tires.

 

http://www.wheels.ca/over-inflated-tires-are-a-bad-idea/

That was a nice write up.  Thx for sharing.  

[SPL Tech]

You say this after I explained my actual experience of 64K miles on my first set of tires on my CMAX with 50PSI with no wear problems, really! ;)

CMAXers want to know what members have experienced, not unrelated info on other cars. IMHO :)

 

Paul

Well good for you, but like I said I have seen it happen multiple times. Those photos are an exact replica of what I have seen in the field on multiple cars. I used to have a Geo Metro and I ran the car at the max pressure listed on the sidewall since I bought the tires brand new. Once the tires were ready for replacement, they looked exactly like the photo above.

 

The manufactures dont just make up the number they post on the door. They know what they are doing. That number takes into account multiple factors including traction, stability, rolling resistance, wear and heat dissipation. You can max out the pressure in your tires but it WILL reduce traction. You are reducing the footprint on the ground, it's not hard to see how that reduces traction.

 

The number posted on the tire is the maximum pressure the tire manufacturer says the tire can withstand, it is NOT the pressure you should necessarily run the tire at. That pressure assumes the tire is loaded to the maximum safe load as printed on the sidewall of the tire. Unless you are running that load, the tire manufacturer will tell you to follow your car manufacturer’s printed recommendation.

 

Mythbusters has tested whether it is a good idea to overinflate the tire. They found it was not. They found the fuel savings was negated by increased tire wear, and it reduced the traction of the vehicle, just like I said.

 

Run the tire at 5 PSI over door stamp and call it done. Going higher than that will just reduce traction. If you get into a crash, your fuel savings are out the door for life. 1,000,000 miles with overinflated tires will save you less money than you will spend repairing just one crash. Not exactly a good tradeoff.

Edited February 2, 2015 by SPL Tech

[C-MaxSea]

38 psi too low for most load conditions (and it only drifts lower (& more underinflated) over time), 60 psi too high, 43, 44, 45, 46, 47 +- cold (and drifting lower over time) just right.  :) :) :)   Just my two cents worth, nothing more.  Driving in the slow lane under 70 mph, mild temps..............  Nick

 

(93Vs - 51psi max load OEM tires)

Edited February 2, 2015 by C-MaxSea

[kblast523]

Hi all, newbie C-Max Hybrid owner here.  My first experience with a hybrid ended abruptly in 2009 why my 'silverfish' 2005 Prius got the dreaded 'screen of death'  The two Toyota dealers in Tulsa both told me to 'walk 'til we can look at it', (a week or ten days out), so I headed to Ford.  ended up with a 2009 Fusion SE 2.3 that was a decent car....fast forward...so was the 2012 Focus SE, but after a trip to Scottsdale in early December, the wife decided it was time to get an 'upgrade'.  Searched Ford and found one new SE white over black cloth, and not another single C-Max closer than 300 miles.  Certified Used produced two vehicles, a 2014 SE in Witchita, Ks, and a 2013 SEL in Stillwater, Ok.  No doubt the Ice Storm SEL Pano was the choice, bought it over the phone, picked it up Dec 24.

Now for the tire pressure issue.  Has anyone read the NTSB Ford Explorer/Firestone Tire report?  Ford specs for the tire and tire pressure on the 1998-2001 Ford Explorer were a perfect  match for disaster all in the name of ride quality.  Jaques Nasser personally falsified the vehicle weight when presenting the specifications to Bridgestone/Firestone engineers who argued the tire needed more capacity AND inflation.  Firestone had been asked to remove 18% of  the shoulder tread which compromised the carry capacity of the tire.  At recommended pressure (26 psi), a Ford Explorer with 325 lbs of passengers in the front seat, 42 lbs in the left rear, would experience catastrophic tire failure of the left rear tire at ambient temperature over 86 degrees, traveling 70 mph continuously, between 42-54 min.

Tire experience I have had on recent vehicles: 2005 Prius, came with Goodyear Integrity 15" tires. Junk and replaced them with set of Yokohama Avid all season at 8k.  Yokos going strong at 35k when traded, ran at 45psi.  2009 Ford Fusion had Continentals that got noisy, but held 45 psi quite well, made 25k miles with even wear and anticipated life near 40k.  2012 Focus wore Continentals smooth out at 20k, running 45psi.  Replacement Bridgestones got noisy at 25k, but showed little wear and two were replaced under warranty just before trade.  Also ran 46-48 psi in these with no trouble.  2009 Ford Flex with Yokohama Avid Ascent Blue Earths that have 40k on them at 40 psi and still have 9/32nds tread on all four, even treadwear, silent operation.  Running 42 psi in  the Michelins on the C-Max, and even though this was a Hertz rental unit in a previous life, all four tires have even wear and 8/32nds at 25k miles.

Happy Motoring, all....

[markd]

Welcome.

[fbov]

To quote the end of Adrian's link:

The Michelin report concludes, “The key learning is that inflation pressure affects the tire-vehicle interaction, and the only correct inflation pressure for proper balanced performance is what is specified by the vehicle manufacturer on the placard."

 

For those who may not be immediately aware, that's written by a lawyer, not an engineer, so it's substantially false.

 

The real "key learning" was to reduce financial risk to the tire manufacturer by never answering the question. Every tire company says the same thing, in hopes that you sue the car maker, not them.

 

As kblast notes, the "correct inflation pressure ... specified by the vehicle manufacturer" is what got Ford Explorer drivers killed.

 

Do we really need graphic pictures of high speed rollover accidents as counterpoint to uneven tire?

 

Frank, who reads specs from sidewalls, not placards.

[Adrian_L]

Frank, with respect:

 

Are you suggesting, in all these years of automotive engineering, that GMC, Ford, Volvo, BMW, you name it can't figure out the safest, most efficient, most economical tire inflation pressure and put it on the placard?   

Seriously? 

[SStoner]

I raised my tire pressures up to the rating on the tire. It's a little stiffer ride and kinda seems to handle better.

[Adrian_L]

My main concern with that would be when the tire gets hot you're over the safety limit put there by Michelin.

 

Welcome to the forum. We're a mellow bunch but some of us get cranky when we misplace our false teeth or walking sticks.

[ptjones]

My main concern with that would be when the tire gets hot you're over the safety limit put there by Michelin.

 

Welcome to the forum. We're a mellow bunch but some of us get cranky when we misplace our false teeth or walking sticks.

The higher the pressure, The lower the tire temperature.  The Tire Companies put a Maximium Safe Cold Tire Inflation Pressue on the sidewall of our tires which is 51PSI for our Michelin's.  You get great tire wear, for me it was 64K mi. before I put on my new ones. :)

 

Paul

[SStoner]

My main concern with that would be when the tire gets hot you're over the safety limit put there by Michelin.

 

Welcome to the forum. We're a mellow bunch but some of us get cranky when we misplace our false teeth or walking sticks.

 

 

The higher the pressure, The lower the tire temperature.  The Tire Companies put a Maximium Safe Cold Tire Inflation Pressue on the sidewall of our tires which is 51PSI for our Michelin's.  You get great tire wear, for me it was 64K mi. before I put on my new ones. :)

 

Paul

 

I would agree with ptjones on this subject. Thanks for the welcome Adrian_L

[fbov]

Frank, with respect:

 

Are you suggesting, in all these years of automotive engineering, that GMC, Ford, Volvo, BMW, you name it can't figure out the safest, most efficient, most economical tire inflation pressure and put it on the placard?   

 

Seriously? 

Very much so! No one can serve two masters, not even engineers...

 

"Engineering" can be defined as the science of picking the right tradeoffs between conflicting requirements and capabilities. Car companies seek tradeoffs that will spur sales and maximize profits, the latter requiring risk analysis and mitigation if they're to keep the money they make. As a result, any publish tire pressure must will work with all tires, not just their OEM choice, for all uses and conditions, as well as all drivers and driving styles.

 

When they get risk analysis wrong, and owners follow the placard, you get the chain of events discussed in post #32.

 

When an owner takes responsibility for their car, based on specific and detailed information the car manufacturer can't know, you get posts like those on this thread suggesting that about 50psi is a good place to set tire pressures with the OEM tires.

 

Have fun,

Frank, whose been known to ignore sidewall pressure ratings when the application warranted.

[Adrian_L]

That sounds reasonable, considering the plethora of tire manufacturers. 

 

Ford deflated my tires to 40 psi when I had my first service.  So I put them back up to 45. 

[SPL Tech]

 

As kblast notes, the "correct inflation pressure ... specified by the vehicle manufacturer" is what got Ford Explorer drivers killed.

 

And you dont think tire manufacturers havent gotten it wrong too? Millions upon millions of auto tires have been recalled, and most of those were recalls relating to reasons having nothing to do with the auto manufacturer.

 

I disagree that the auto manufacturer is not the best resource to determine the tire pressure. Here is why. The tire manufacturer has no idea what vehicle you plan to put the tires on, so there is no possible way they can recommend you an optimal inflation value. A 2000 lb car is going to have a MUCH lower optimal tire pressure value than a 4000 lb car with the exact same tires. Choosing the wrong tire pressure WILL cause increased wear, reduced traction, higher risk of deflation, high risk of rollover, ect, and the right pressure depends heavily on the vehicle that the tires are attached to.

Edited March 3, 2015 by SPL Tech

[Adrian_L]

At the risk of flip-flopping, that makes complete sense.  

 

Filling your tires to 50 psi is probably not going to do much harm, but arriving at that number from a non-scientific "feeling" that the car rides better is kind of like picking oil based on how it feels between your fingers.

Edited March 3, 2015 by Adrian_L

[SStoner]

Tires have a stamped max PSI rating on the sidewall. Our factory tires to rated @ 51 psi.

[ptjones]

To me the right tire pressure to use would be the tire pressure that gives even tire wear, 50PSI for the CMAX from my experience. Which is below 51PSI for our Michelin's, to have lower is waste of gas. IMO

 

Paul

[edward stewart]

Well looking at the debate on the tire pressure, everyone might find this interesting. I keep my car at the ratted psi for the car. In this traffic you never know when someone will cut you off in your comfort zone or when you'll be driving on wet roads. 

 

Well anyway, the last time I had my card serviced at a Ford Dealership, back in March, my tires were inflated to 45psi. vs. th 40 on the door. I was not a happy camper, still need to talk to them when I go back in about 1k miles.... but the statement I got when I took it in was they set the car to spec. Happy camper when I discovered they had upgraded to 0w-20... can't really find anything on the tires... ya this is in another thread, but thought I would pass it along in this one.  

[edward stewart]

Just had the car serviced yesterday. Inquired about getting paperwork on a psi update paperwork.... got the ... The pressure gauge must have been faulty, we will test with two different pressure gauge excuses. 

 

Some please remind me why I'm paying premium prices at a dealership, vs, having my co-workers at Wal-Mart do it in the automotive department (17 year associate, there might be a incident or 2 year at my store.) ???? I could have slept in, checked in my car at work, clocked in, and left at the end of my sift. 3 hours of my life gone. 

 

Do the dealerships even check the fluid level's in the CVT, plus color to see if its burned up, or do they just look for leaks???? Is there a after market solution to adding a dipstick to the CVT????

Edited July 11, 2015 by edward stewart

[ptjones]

FORD will set the PSI to what is in the door jam unless you tell them different. I'm pretty sure to say that my Trans Fluid was never checked, there were no leaks so it must be good. ;)

 

Paul

[cheezy]

Brand new owner here looking to take a 300 mile round trip on the highway.

Any suggestions for maximizing MPG @ 65 mph?

Thx

 

45-50 PSI in tires, use ethanol free fuel, have the oil level in your car at the halfway point between the 'stick marks of High & Low.

 

If your commute is nice and level, NOT hilly, use the Eco-cruise function.

 

Enjoy.

 

Our Dealer I just picked the car up from had the Oil level over the "Full" mark and the front tires were both under 40 P.S.I. Simple fixes. 

 

Enjoy!!

[Bugblndr]

Some please remind me why I'm paying premium prices at a dealership, vs, having my co-workers at Wal-Mart do it in the automotive department (17 year associate, there might be a incident or 2 year at my store.) ???? I could have slept in, checked in my car at work, clocked in, and left at the end of my sift. 3 hours of my life gone. 

 

 

Good question. My 2011 Toyota Highlander Hybrid never went to the dealer after I picked it up. 85,000 miles, 4 years, not one visit to a Toyota service department. 

 

I had all maintenance done at a local Jiffy Lube, or an independent garage across the street from my work, or the shop my wife worked at.  I saved a ton of money and sacrificed nothing by doing so IMO.

 

My C-Max will definitely have at least it's first service done at the Ford dealer since there's already been a recall on it.  My wife works at the dealer I bought it from so the pricing should be reasonable at least.