Tire Pressure does make a difference!

[TonyPSchaefer]

I'm not going to attribute it entirely to high tire pressure, but I just finished my second-in-a-row personal record tank average: 63.0. One month ago - on the urging of excel - I upped my tire pressure to 50/48. Hey, he wanted me to go 60/58; I compromised.

Anyway, I've been working harder at pulsing and gliding and trying to refine my light foot touch.

So I don't want to attribute the 63MPG exclusively to tire pressure, but I feel that it's definately a piece in the puzzle.

[nerfer]

<div class='quotetop'>QUOTE(tumbleweed @ Sep 5 2006, 09:55 AM) [snapback]314519[/snapback]</div>

I haven't done any mileage tests on the Prius to determine the effect of different tire pressures but I did do some tests on my previous car, a Honda Accord. I drove it for several thousand miles on the highway with the tires at 32 psi (psig actually) and then increased the pressures to 42 psi and rechecked the mileage. The weather was very close to the same, I went over the same highways at the same speeds, etc. The mileage increased by about 10% with the higher tire pressures.

An unrelated question, I notice most PC people maintain the 2 pound front/rear difference. Does it really make any difference? I have tried 42/40 and 42/42, I have tried 44/42 and I am currently running 44/44 and I can't tell that the 2 pound difference between front and rear matters.
[/b]

I keep the 2 pound difference, at 35/33 that's a 6% difference, but if you go up to 42/40, then it's a little under 5%. Probably still enough. I'm like you though, I took the car in to the dealer for the 5K, they told me they rotated the tires and checked the pressure, etc. I made a mental note to make sure they didn't drop it back to 35/33 (I keep it about 39/37), but with the rush to get ready for vacation I didn't do it until I drove to Minnesota. There I found out they simply rotated the tires, and I had 37 up front, 39 in back. I corrected it, but couldn't really tell the difference. Maybe if I was on a slalom course with smooth pavement I might notice...? Roads in northern Minnesota aren't known for being smooth, but the Wisconsin interstate was fine.

<div class='quotetop'>QUOTE(TonyPSchaefer @ Sep 15 2006, 12:44 PM)</div>

I'm not going to attribute it entirely to high tire pressure, but I just finished my second-in-a-row personal record tank average: 63.0. One month ago - on the urging of excel - I upped my tire pressure to 50/48. Hey, he wanted me to go 60/58; I compromised.
[/b]

Hey, that's not fair! I have the same weather as you, and this last tank was bad! (About 48 mpg). Of course, I filled up on the coldest day of the week after the hot spell (we went from the 80's to the 60's in one day), so the gas was more dense...that's my excuse, at any rate, and I'm sticking to it. I'll see what happens on this tank and average the two together, maybe I really topped it off this time, but I don't think so.

[windstrings]

<div class='quotetop'>QUOTE(TonyPSchaefer @ Sep 15 2006, 10:44 AM) [snapback]320168[/snapback]</div>

I'm not going to attribute it entirely to high tire pressure, but I just finished my second-in-a-row personal record tank average: 63.0. One month ago - on the urging of excel - I upped my tire pressure to 50/48. Hey, he wanted me to go 60/58; I compromised.

Anyway, I've been working harder at pulsing and gliding and trying to refine my light foot touch.

So I don't want to attribute the 63MPG exclusively to tire pressure, but I feel that it's definately a piece in the puzzle.
[/b]

I thought about going higher.. but the hot summer weather around here made me go chicken.....