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How much fuel will higher tire pressure save ? ie going from say recommended 32 psi to say 42 psi - ball park percentage number
I know there re are a lot of variables.
Looking to improve 2005 Toyota tundra double cab truck mileage and open to all suggestions. Truck is in very good shape and well maintained with Mobil 1 oil in every thing.

i.

Big part of the advantage is longer glides, so if mashing the brakes all the time the savings will be less.

I'd guess 5-10% improvement. If combined with other hypermiling techniques, then much more is available, depending on how it was driven before.

You can feel a tire at 32 after running at 42 for a while, so definitely measureable.

Remember the tire pressure stuff at the last presidential election?

Yes, it makes that much difference.

I suggest you get a good baseline, then bump it up in chunks until the feel makes you uncomfortable.

As kstat wrote, you get the greatest benefit when you combine inflation with other hypermiling techniques.

If you inflate high you'll be working a smaller spot on the tire harder, so if you're heavy on the brakes you've more chance of premature wear. Hypermilers avoid braking and particularly heavy braking, so even with high pressures their tires last a long time. Hypermilers generally believe the concern about premature wear is overstated.

Hi Stew:

2% tops from an increase pressure and measure your FE delta. As Ksstathead mentioned, glides can be significantly increased and when you throw that into your daily repertoire with higher pressures, you will see a much more significant savings.

Wayne

A safe start is 85% of side wall max pressure. 44 psi max side wall warning means 38 psi is a good start. From there bump it up a pound or two and drive it for a few weeks and see how your mileage and tire wear looks to you. If every thing looks good and it rides well then bump it up another pound or two.

In my case I run 44 psi front and 42 rear (Summer tires) on my Prius side wall says maximum 44 psi and door sticker says 35psi. I have zero wear or driving issues at those pressures.

On the other hand my Volvo is a handful with 44 psi in the rain. It gets a little too responsive or twitchy which is something you don't want when driving in the rain. :eek:

Due to this high pressure handling problem I will not run pressures above 42 psi
Door sticker BTW is 36 psi.

One note is I have found that door sticker pressures are low in many cases.
The manufacture is more concerned about ride quality than fuel mileage or tire wear.

For me its closer to a 10% increase due to tire inflation alone. My wife has no idea what I do with tire pressures- as the primary driver she gets a 10% benefit in mpg in the Highlander, with no change in technique.
Regarding wear- the old Bridgestone duelers wore more quickly in the center after I bumped the pressure up, but they were already in the last 1/3 of their life. Haven't seen a negative effect on my skinnier Saturn tires over 40000 miles.
I'm a real believer in higher pressures, enough that I'm running the new tires and the snow tires on the Highlander at max sidewall rec. pressure even with the Dueler experience.

Keith

My car calls for 32 psi.
My tires are rated for 44 max psi.
Last set I ran at 38 psi and they wore out on the edges - classic sign of underinflation.

I run sidewall max (or higher ;)) now.

I ran over sidewall on my Primewells. They are rated for 40k miles, I have had them on for about 52k and I am just now starting to shop for new tires. Wear is a little uneven due to an alignment issue that I haven't had the money to address.

For much larger size tires such as truck tires, I have experienced more than 10% with an increase in pressure from "door post recommended" to sidewall.

Some numbers: http://www.cleanmpg.com/forums/showthread.php?p=296986&highlight=michelin+psi#post296986

Thanks for the replys