Now that it is getting cold, I want to make sure my tire pressure is correct. I know some people say to fill them up more than what they tires say. What do you guys keep the tires at? Thanks!
I'm keeping mine at 38 front / 36 rear, but it varies from owner to owner. There are quite a few on this board who run 42/40.
<_< "Correct" tire pressure ?? Well... that's a matter of personal preference. I keep mine at 40 psi front/38 psi rear. Generally speaking, the higher the pressure, the greater the fuel economy within limits -and- the higher the pressure, the rougher the ride, also within limits. I purchased a high-quality analog tire gauge and a 12v small compressor to keep my tires at accurate, balanced pressures to extend tire life and get reasonable fuel economy. These "ride" in the small storage compartment in the cargo area left side. I check my tires at least once a month "cool" an hour or more after the car has been parked.
There is really no "correct" tire pressure, it depends on where and how you drive. I consider the pressures listed by Toyota (35/33) as the minimum acceptable; the pressures on the sidewall of the tire is the maximum I use (usually 44 lbs for most tires). If I were going to be driving on gravel roads with sharp rocks I would use lower pressures, if I plan on staying on the pavement I use higher ones. Presently I have all four tires at 44 lbs cold. Higher pressures give you better fuel mileage and better resistance to hydroplaning. Lower pressures have better resistance to some punctures, give a softer ride, and slightly better grip on dry pavement, or so I have been told. The only thing I can attest to personally is that higher pressures definitely improve fuel mileage and the difference in ride is, to me at least, minimal. A lot of people on this site swear to 42/40 or 44/42 and that's fine. I don't bother with the 2 lb front/rear difference because I don't think it makes any difference.
<div class='quotetop'>QUOTE(yarzy @ Sep 28 2006, 08:10 AM) [snapback]324997[/snapback]</div> We keep our tire pressure at 40/38. Check tire pressure after dealer service; some are known to reduce pressure back to "Toyota specs". Some of them also "know" that they should use 4 quarts of 10W30 when they perform an oil change on the Prius (wrong on both counts...) Richard
<div class='quotetop'>QUOTE(yarzy @ Sep 28 2006, 08:10 AM) [snapback]324997[/snapback]</div> Don't put in more than is printed on the side of the tire. Sure, there's some safety margin built in, but exceeding the maximum rating is asking for trouble. Maybe more to the point, if anything did go wrong you could not blame the tire for it. (Understand that tire pressures should be measured "cold", which means that the tire has not been driven more than a few miles during the previous hour. If you measure tire pressure immediately after hours of highway driving the pressure might easily be greater than the maximum rating, but this is normal and safe.)
While PC was down due to the recent hack/crash, I spent some time over at greenhybrid and cleanmpg. After reading reports on the Escape Hybrid boards and the hypermiler tips, I'm going to settle on 44/42 (I run 42/40 right now.) Lots of people apparently run something like 50 with no ill effects. :blink: I don't have the courage to run above 44, but I'm all for taking it up to the max! I don't think the ride feels any worse.
This is a good time of the year to remind people that for every 10ºF drop in temperature the air in your tires will compress enough to lower your tire pressure by 1 psi. So if you are running 40psi at 70ºF. You are running 37psi at 40ºF. Here in Chciago, you'd be running 33psi at 0ºF Additionally, you would be running at 28psi at -42º but I'm not sure if that's Celsius or Fahrenheit .
<div class='quotetop'>QUOTE(TonyPSchaefer @ Sep 28 2006, 01:07 PM) [snapback]325104[/snapback]</div> Well it turns out at -42 dF is approx equal to dC
