Oscars_3748

I have sceen many saying that having your PSI at 42 will icrease your MPG. Now I didnt get my GT to save gas, however when ever anything simple as that can save me some cash, done deal

Stang-aholic

It might help some but not a remarkable difference, your car will ride a lot rougher though. i run 36 front and 34 PSI rear.

Nuke

+1 on riding rough. It can be a real kidney killer at that kind of pressure. It'll also affect handling but will increase your mileage by a tad; maybe 1-3 MPG. IMO, it's not worth it. I experimented with my tire pressure at 1 PSI increments from 28 to 36 and back and found that I like 33 PSI all around for my style of driving. Of course, that will vary from tire model to tire model.

Oscars_3748

Thanks Nuke and Stang-aholic! I'll mess with it and see what i get. It wont do anything to my tries thou right?

Nuke

Running 42 PSI over time may wear the center of the tread faster than that close to both edges. The TPMS may alert at tire pressure below 26 PSI if I recall. Other than that, have fun and learn!

Norm Peterson

Many of the "hypermiling" tricks vary between looking at only mpg (ignoring all else) and being downright dangerous. I'd swear those guys have blinders on to anything except hanging on to the last drop of gas. Less extreme versions of what you hear from that direction may be useful, however. Just remember that moderation is key.


Uh-uh. No guarantees. Impact damage is more likely to occur if the tires can't "give" a little when you hit things like potholes or large "steps" on driveway entrance ramps. Obviously, "giving" too much is no good either (think pinch flats). There's a range in the middle where you have room to experiment a little, as far as this is concerned.

Do plan on greater center tread wear. Run some numbers like 1 mpg better economy at whatever the prevailing gas price happens to be vs the replacement cost of two tires. How many miles to the break-even point if your tires last only 2/3 as long?

Do plan on having less grip on a bumpy road. A tire that's bouncing upward has less grip than a tire that will conform a little better around the small bumps. Worst case is a tire bounced clear of the pavement (it then has no grip at all).


It's one thing to temporarily air your tires up a bit to sharpen the turn-in response and/or tweak the handling for autocross or open-tracking. Quite a different thing to maintain them up there for extended periods of time/distance.

I've run as high as 37-ish on the street for extended use in another car, which I also autocross. And I've run up to about 36 in the Mustang's front tires. I'm back down to 34-35 front, somewhere in the 29-31 vicinity rear (and yes, I know).


Norm

Legion5

Toyota Prius 1st gen test:


This shows 3% for 11 PSI.

GM also did a test where they found 4% for 10 PSI.

Finally a magazine tested the mpg increase of overinflating low profile tires. With low profile tires they found instead of 4% for 10 PSI as usual you get 3% for 16 PSI on 80mm sidewall tires.

d_ames117

Good info.

Ames

nmd55

i run 40psi on my 20s all the time. in vain hopes of protecting the rims.

Mustangmaster

Ford has done it's research on what gives the best economy and best comfort for their cars. The 32 inside the door is there for a reason. It's the best overall. I have tried all kinds of PSI settings and agree with Ford. I did get 2-3 mpg better when I pumped my tires up with higher PSI but it felt like I was riding on a roller coaster. The hypermiler are fooling themselves. The PSI pumping does make the center wear quicker and they'll be buying tires sooner than they should. So, they save gas but have to buy tires quicker. So, you either pay for tires or gas. Take your pick. Maybe it makes them feel better to buy anything rather than gas.