I put more air in my Prius tires and instantly got 5 more miles per gallon

[Beaverhausen]

I had read that it's good to have them at 40/38 psi but for some reason I waited until last weekend to fill them up.

My average MPG went up 5 miles.

That's my tip for the day! :hi:



Yes, the ride was a little bumpier. Who cares?

[phantom power]

1. Rolling friction. The silent killer (of mileage).

[benburch]

2. Oh yes!

That is well known to the Prius users groups.

The tires live longer too.

[Beaverhausen]

5. I know- I read that 4 months ago on Priuschat - so why did I wait?

I have no excuse!!! :cry:

[tanyev]

3. Hubby noticed that on his VW diesel, too.

He had been keeping them at 30 something until he noticed the manufacturer's recommendation was closer to 40. Shazam! Better gas mileage.

[merwin]

4. Watch out in wet weather, as highly inflated tires will cause them to lose

grip easier.

It's a tradeoff.

[Beaverhausen]

6. It never rains here in Southern California

really...it doesn't. Well, almost never. But I will remember that when it does.

[benburch]

9. Seems I've often heard that kind of talk before... nt

[formercia]

10. Just a sprinkle is even more dangerous

The combination of oil on the pavement and a small amount of water is very dangerous.

[Beaverhausen]

12. I know. People back east can't believe I "don't like to drive in the rain"

It does get crazy here when any precipitation hits the roads. But for now, I'm keeping my tires where they are.

[formercia]

16. Be safe and know the limitations and above all,

watch out for the idiot that hasn't got a clue.

[RogueBandit]

8. Bad on ice, too

I came down a steep grade after putting on my front-drive chains. Within 3 minutes I had slipped on the ice without any slowing down or speeding up or changing direction. I was going about 10 miles an hour. The rear tires had been overinflated to carry luggage one way, but not reduced for the return trip. My guess is that the rear tires slipped out, since I did kind of spin around the front tires.

Otherwise, I have read that we could decrease automobile fuel consumption by 15% if everyone checked their tire pressure regularly. Makes sense to me.

[northofdenali]

11. In winter, I sacrifice a little mileage for safer tires.

Because snow studs tear up the roads so badly, we keep our tires at factory recommended inflation during winter (really decent traction) and overinflate some in summer for better mileage.

Here, it's a toss-up between safety and savings. Most times, especially when it's really cold, safety comes first.

BTW, welcome to DU! :hi:

[MercutioATC]

15. Overinflating tires can also result in wear problems.

More is not always better.

[CountAllVotes]

7. I just added a bit more to my Honda

The tires were low. I put a little extra air in them (abt. 2 lbs.) and on the last fill-up I figured I'm getting about 28 mpg which is a vast improvement over the 20 mpg I was getting!

*eek*

It is a good idea to check the tires regularly but I'd still stick within the guidelines that the owner's handbook recommends for inflation of tires. I'm sure there is a good reason for this.

I don't know what is recommended by Toyota for the Prius you have.

[EST]

13. Each 7 degrees of temperature change equals one

pound difference in tire pressure. Each two pounds of tire pressure equals about 1% mileage difference (this number bounces around, depending on car size, power, etc, but it can be quite dramatic.) Most tire pressure recommendations are on the low side because of passenger comfort considerations.

On front wheel drive cars, the experiments we did shows there should be at least a 10 pound differential front to rear such as 38 front, 28 rear. Another consideration they use for tire pressure recommendations is the likelihood of operator remembering to check and the complexity. They try to make it easier to remember.
Over inflated tires are very dangerous even in dry weather. The biggest problem is over inflation of the rear tires--they have a tendency to bounce like a basketball: think how a basketball bounces when it is pumped up hard.

What happens is the car has a tendency to over steer, causing it to swap ends in a hard or emergency maneuver, causing total loss of control.

There are some other things that get a little more complex, such as checking ride height to determine what pressures work best.

On edit: under inflation is often even more dangerous because the extra flexing causes severe deterioration of the tire body, usually invisibly, causing blowouts as well as loss of control from instability.

[DarkTirade]

14. That works for just about every car.

I drive a 1990 Honda Accord, and my milage went down to 25 mpg when I had a slow leak in one of my tires that kept making it slowly flatten out.
When I got around to spending the 20 bucks for a used but still good tire to replace it with, well, I'm pretty sure I've saved a helluva lot more than 20 bucks in gas since. :)

[Bamboo]

17. Friction from extra oil in crankcase like low tires.