From 31 H-MPG to 36 H-MPG *Tire Pressure
 

I have noticed by upping my tires PSI to 40 it has helped gas milage significantly .

When I was running 32PSI I was averaging 31 MPG Highway. Past two months Ive been running 40PSI and I have been averaging 36 MPG Highway

22 mile commute each day to work and back. (44 miles total daily)

Keep an eye on uneven tire wear .

Sorry, but increased tire pressure will not yield that type of results.

I would watch for 2 things: premature wear in the center of the tire (the tire is not "sitting" on the road with its full width)
On tire could actually explode - you're running 40 psi - that could weaken the steel belts - speaking with logic on this, I don't know for sure, haven't heard cases or had experience with it

Running 40 psi should not be an issue at all for any of the 17" or 18" UHP tires.
Acura actually recommends 39 psi for the front tires on any TL using the 18" A-Spec rims, and the owner's manual also recommends 39F/36R on the 17" wheels for sustained high-speed (118 mph+) driving.

Tire construction during the past 20 years also allows for regular street operation at 40 psi. I wouldn't run beyond 40 psi for regular operation (as opposed to track or autocross) though, partly because I grew up in an era where bias-ply non-radial tires were more common than radials.

However, a higher rear tire pressure (with less pressure differential between front and rear) may permit a little more understeer/plow when driving closer to the edge.

It's a good idea to keep an eye out for uneven wear while running 40 psi. I always run 36-37 psi up front and have yet to encounter uneven wear, from either the OEM MXM4s or the replacement S4s.

I run 38psi in the front and have been getting 33-34 mpg on long trips (260miles) at 70mph. I dont really perform and hypermiling techniques, But I will try stay a very safe distance behind trucks/cars going 70mph if possible. I also coast alot if I see braking will be necessary, and I wont accelerate hard. When getting an alignment recently they commented on my tire pressure saying that it would cause uneven wear, but ive driven a ton of miles like this, no problem.

must be nice to get those type of numbers, i guess i drive to fast, 24mpg is good for me

Maybe thats why my mileage dropped since I bought the car. Bought it was getting no worse then 19mpg and then as the temp cooled I have been getting 17mpg and I noticed the tire pressure has been 32psi versus the 38-40 it had when I bought it.

I've been running 36F & 34R for a while now but I've been reverted to 32 all the way around by the dealership twice now. I drive 124mi for my daily commute which is about 95% hwy. When set at 32 F&R I average 28mpg while averaging 32mpg at my staggered pressures. That being said, I don't think it's unreasonable that louisville88 is getting that kind of mileage. I would, however, warn him that 40 F&R is too high and very dangerous as I ran 38 F&R for a minute and was hydroplaning everywhere (orig EL42's). That was a little too scary for me (albeit I run between 80 - 90mph to and from).

<- also from louisville

40 psi is no problem as many tires have a 50+ psi max rating, however, you won't see a 5 mpg increase by increasing the psi 8 lbs. If it were that easy, the manufacturer's wouldn't be scrambling with lighter cars, more fuel efficient engines, they would just construct a vehicle with soft suspension and put 45 lbs in the tires and then you'd have a V-6 that gets 40 mpg highway.

EL42's max at 40psi (just fyi)

MID don't lie (well, that's not exactly true).

http://farm3.static.flickr.com/2235/...e5e5043796.jpg

Running 36psi cold front & rear. Maybe mine is just more aerodynamic. :boink:

could partially be caused by a switch from 'winter blend' gas to 'summer blends'? any thoughts

can't rule it that out. good call. ymmv.

For your FYI-You'll find that the 42's are 44 PSI max

I'll repeat, you're not going to see a 5MPG increase when raising the PSI to 36, and you can get the MID to register just about any MPG in a short period when on the highway, tailwind, downhill, neutral, will do wonders with the MID mileage. Got the daughter's Hemi Grand to show 24 MPG on the highway once, but overall she sees 13 if lucky.

dude probably changed his driving habits either on purpose or inadvertently.

I can get 36 mpg doing 60 mph on tires at normal pressure, for about 100 mi

:werd:

you will not see 5mpg go up when u pump 5more psi in your tires....couple things you wanna take care of:

1> Uneven Tire Wear
2> Most tires max psi is 43-46....40 cold psi mean you are pretty much pushing the limits....
3> Maybe your driving style changed....i get 33mpg hwy all the time....got picture proof....

I ride at 35 cold psi....and get amazing mileage....i have upped it to 38-39 and got the same mpg....

do yourself and ur tire a favor....turn it down to 36 or lesser....

I do stand corrected. For my for my information [sic], EL's are indeed 44psi max cold.

".i get 33mpg hwy all the time...." yep, same here with exception of the sweltering summer heat/humidity which dropped me to 29mpg average over 9,600+ miles.

45 miles is hardly a decent statistical sample. I can get >50 on a 10 mi long down hill stretch it is going up the otherside that kills my mileage.

X2 also .. put 40 PSI in the tires when the tire is cold then run it a while in the afternoon on a summer day and check them .. that can run as high as 50 .. .. be careful in the summer.