15 more PSI = 7% better MPG

[rauch]

where are you filling your tires at? Do you have a compressor at home? I was going to go up to 45 lbs on the truck today but the dinky compressor at the gas station wouldn't pump more than 35 lbs

[Saskwatchian]

Try another gas station? Most keep their compressors at 100+PSI, at least over here.

Or you can buy a small compressor that plugs into your cigarette lighter for not much money. I don't leave home without one.


Different vehicles react differently to different tire pressures. I had a ranger and it had to be at 32-35 PSI, any higher and it would be bouncing all over the road. I have a versa now which seems to handle better at 40 PSI than the recommended 32.

And another thing to remember is if you are driving off the black top or on broken surfaces the higher your tire pressure the more susceptible you are to flats.

[Joggernot]

Originally Posted by rauch

where are you filling your tires at? Do you have a compressor at home? I was going to go up to 45 lbs on the truck today but the dinky compressor at the gas station wouldn't pump more than 35 lbs

Our newer stations have air stations that will fill the 51 lb on the truck. Might try a newer station or one with a new air station.

I also have a very slow compressor from AutoZone that will "go up to 300 lb", but it takes forever to get to 42.

Joggernot

[101Volts]

The Sheetz gas station a few miles away from me has an air compressor which will go up to 70, Easily.

[CoClimber]

I don't follow this forum much so this might have been covered but I have reservations about over-pressuring tires. First, it seems to me that some of the pressures quoted on this thread sounds like a blowout in the making. Second, I would imagine that very high pressures would make for uneven tire wear, negating the savings of fuel consumption from more frequent tire changes.

For my third point I should qualify and say that I have a fair amount of experience working with tire pressures to change a cars handling characteristics, specifically in a racing environment. We can control understeer by lowering front tire pressure or raising the rear pressures. By raising the pressure, we are making the tire grip less. In normal driving conditions this is unimportant but in the event of an accident situation I want as much traction as possible to allow me to perform evasive maneuvers like hard braking or turning.

Having said that, one of the aspects of hypermiling is situational awareness which will have the added benefit of reducing the likelihood of an accident so maybe there is a balance there.

Just some points to ponder. I am all for hypermiling but not at the expense of safety.

[101Volts]

CoClimber, I read that Diesel Dave has tires on his truck which are rated to go as high as 80 PSI safely.

[Joggernot]

6-ply truck tires are rated at 80 psi. My father-in-law ran these on his truck and ran 80 psi all over the USA towing a 5th wheel.

[gone7]

I wonder how it felt without the weight of that fifth wheel.

I would never think that auto engineers ever design with the thought of selling more tires. Therefore, they are considering safety (maybe including their own liability), handling and comfort. It would be wise to consider each of those when doing comparisons of tire pressures.

There are huge numbers of reasonable people who would simply not care if they spent an extra hundred dollars per month to have a more comfortable ride. And that's just one issue.

[cbaber]

When I considered going over the max sidewall pressure, I thought it was interesting all tire brands seemed to use 44 or 51 PSI as the max. It seems those numbers are not necessarily based on the limits of the specific tire, but rather some industry standard. Are you going to tell me brand X and brand Y both designed their tire so that it could safely handle 51 PSI? And even if it was the true limit of the tire, the designers would have given it a pretty wide margin of error. Meaning if tests indicated that a tire will bubble or burst at 80 PSI, they are probably going to set the max pressure lower at maybe 60 PSI so that nobody even comes close to the actual limit. They would have to account for inaccurate filling station gauges and other factors.

And we have already discussed how center tread wear on over-inflated tires is not as true as many would seem to believe due to the modern construction of tires. Uneven wear is more likely due to poor tire maintenance like not rotating and not getting alignment checks.

But even with all that, MetroMPG already showed us that beyond 50 PSI the mpg gains taper off significantly. The benefit of running 60 PSI vs 50 PSI might not be worth the risk of going over the sidewall limit in some cases.

[CrazyLee]

Yah. LB would be a big bonus. It tends to replace P&G, I think. Someone with experience behind the wheel of one with working LB will chime-in I hope.

Hi, I like driving with LB. (Lean Burn) I only wish they would make a cruise control regulated by LB.

The trick with LB is lifting the gas pedal often causing the ECU to load the LB fuel map. The lift can very small as you will notice if you have a fuel gauge (FG) in your car. Just lift quickly and press it back down to the level you were at. Experiment to see how quickly you can do it. Quicker the better since you won't lose any speed. You don't have to lift all the way either.

By watching the FG you can see when you drop out of LB. Keep your eyes on the road though.

A neat trick is accelerating in LB by very slowly adding gas pedal pressure. If it is slow enough in pedal pressure the ECU is fooled into holding LB. It is easy to gain 5 mph in a Minuit.

When approaching a hill slow accelerate in LB if possible. Then hold the gas pedal absolutely still. This also fools the ECU in holding LB while going up hill. The vehicle speed drops and the fuel burn increases some, but stays in lean burn. You can prove it by pressing down on the gas pedal and watch the mpg drop.

My vehicle that I started with is The Beast. I added a FG to my Chevy Venture and improved my long distance driving by 10 mpg.

The Beast (a 12000 lb motor home!) is in the Garage & Tools 15 mpg.

CrazyLee