I am aware the tire pressure should be set at 33 psi on cold tires. My question is, what is considered to be cold? I live on Long Island and it is stupidly cold right now, like 15 degrees today. I keep the car in my house's garage which is a little warmer but still very cold. My mechanic recently plugged a hole in one of the tires and overfilled all 4 to about 37 so tomorrow I want to lower the pressure in the 4 tires. Should I put the car in my driveway tomorrow for an hour or so and get them as cold as possible or set them in the garage? Opinions?
Thanks, Dave

 

In my opinion 37 lbs should be just fine for cold weather. You'll get a little better mileage too. A couple of weeks ago it was in the 30's and I filled my 18s to 36 lbs stone cold. Now it's about 5-15 degrees out and my tires are running about 34 lbs stone cold (sitting overnight). Yes, the colder it gets the lower the pressure, thus 37 = ok because if you run them on interstate they will just not get hot enough to make them too hard.

 

I air mine up when cold to 35 psi and run that year around. Works great.

 

From Bridgestone tire web site:


Tires are considered cold when the vehicle has been parked for three hours or more, or if the vehicle has been driven less than a mile (1.6 km) at moderate speed.

 

Good point. When I check mine and if they need air. Its the first thing I will do early morning before using the car at all.

 

33PSI cold is based on comfort, reasonable tread wear, and best overall performance and safety as suggested by Nissan. That doesn't mean you can't fill the tires up more or less depending on conditions. Look at the sidewall for ratings, most tires these days have max PSI of 44, some over 50, all cold measurements. It doesn't mean you should fill them up to that number, but of course you could. You can also lower pressure for extreme traction conditions, but that's more with all terrain tires then with street tires. All that said, your tire guy filled you up to 37 inside the shop at say 60 degrees, chances are that's a good number considering your wheels will never warm up if the temp is 15 degrees. You'll likely be at 29-32 even after driving if that 37 psi was done at say 60 degrees "cold". Now, if you expect icy conditions, I'd suggest you consider lowering PSI for that reason but be sure you don't go so low you have problems as it get's colder. Leave the car outside for an hour or so, check cold pressure then. If still at 37, then drop that psi to say around 31-33. Even could go a little lower, but don't expect much performance in icy conditions no matter how soft you go. Reality is you should have snow tires if you want to keep traction in the trouble spots.

 

Well put MadMax.

 

Expect a 1psi change for every 10°F change in temp. So check your ambient temp trends ( say if the trend is about 35°F to 40°F in the morning during winter months such as in Louisiana where I live), then inflate the tires accordingly. In other words, you check tire pressure during the day when its 60°F, but you want to make sure you have at least 35psi in the tires in the morning when its in the 30's, then fill up to 38psi (3psi additional for the 30°F change).

 

I thought the 8th Gen was equipped to monitor real time tyre pressures in the instrument cluster or control panel display. An initial pressure of 38psi may be considered optimal to accommodate weather/temperature changes over a reasonable period of time .

 

Yes, the tire pressure can be displayed in the control panel display, and that is exactly the display I keep up there. I keep all four tires at 37 psi cold, which, as expected, rises slightly in higher speed driving in cool weather, and rises a little more in warm weather. Carrying 37 gives me more grip in turns, and, with my style of driving, seems to give me extended tire life, usually over 50K miles, and gets slightly better fuel efficiency than 33 psi. I do check the tread depth in all grooves of each tire every three months to confirm even wear across the face of the tread.

In especially hot conditions, I set all four tires at 35 psi, so freeway driving will not cause the pressure to rise over 39 psi. I don't think pressure over 40 is as safe as pressures under 40, as pressures over 40 not only tend to ride rougher than comfortable and wear the center portion of the tread faster, but, sometimes cause the car to sort of 'bounce' over some type dips and humps in the road.

I must say that several posters have put very good info in this thread, and I enjoy reading thoughtful and informative threads.

 

Yes, I quite agree with LOTH on the 40psi rule. As a matter of fact I do not allow my tyres to go above 40psi even at the hottest conditions. Because I live in a tropical zone where temperature changes are not so drastic I keep my initial readings at 36psi; with that I hardly go beyond 40psi even after hours of driving in temperatures as high as 35 degrees centigrade. Temperatures in the mornings seldom fall below 28 degrees, so the 36psi in the tires is hardly affected except of course by the gradual leakage over time. I drive a 2006 Infiniti M45 and, again like LOTH, my control panel display is permanently kept on the tyre pressure monitor.

 

I live in NJ were it has been below freezing every day. Of course this is abnormal (it's at least 20 below normal) and my psi has been hovering around 30/31 when I start out. I had set my tires at 33 on an average December morning and they now warm up to around 33 in this bitter cold.

I noted last winter and this one that - once warmed up - the front tires are around a couple of degrees warmer than the rear, and the front left tire is consistently a degree or two above the front right.

(I matched all tires cold with a digital gauge before driving.)

Why? Does the warmth of the engine account for the front/rear difference? What about the difference between the two front tires.

 

The low air warnings came on today, probably due to the freezy weather we've been having (yes even here in the south).

So an interesting question came to mind. There is a feature where the car will beep at you when you hit the correct PSI when filling your tire. How can it do this when the car is stationary , yet you have to drive for a bit to get readings of all your tire pressures?

 

I've tried using the tire pressure warning on my SL when filling up the tires, and - even after following the directions - could not get it to work consistently.

Anybody else having issues? Suggestions as to using it?

 

if you change the pressure even before driving the car (add or reduce), the computer will read it right away and display it. does not need to wait to drive a distance to show. my $10 digital reader is quite close to the car’s display. try it out if you haven’t.

 

Type and style of driving enter into this. The front tires do 100% of the work moving the car forward, most of the work turning the car (especially at speed), and most of the work in stopping the car,( especially from speed). This sometimes (especially in warm weather) builds the psi in the front tires a little higher than the rear tires if they all started at the same cold psi. I have found another sort of odd anomoly - If I drive with full sun shining onto one side of the car, the psi in the tires on that side gradually rise a pound or two higher than the tires on the shady side. I have not noticed my left front tire psi getting higher than the right front tire except in situations where the left front is in full sun while the right front is not. It would be interesting to know if others here have experienced EdOz's left front divergence from the right front.

My wife and I are **** about our tire pressure, and have been pleased to note that, during the last several months, the psi on all four tires has stayed at 37, except slightly higher on freeway trips and measurably lower during this bitter cold weather. But all four are reading exactly the same at all times. As driving situations and styles, weather, etc change or adjust during spring and summer, I would expect to see some variation gradually begin.

Driving in this cold weather with all four tires a little lower than the Nissan suggested 33 psi hurts nothing, but if any tire drops much lower than 30 psi, the tire pressure warning system will light up. I would never drive over 70MPH with a tire reading below 30 psi. Excessively low tire pressure results in the profile of the tire dropping out of its designed operating profile, resulting in uneven and excessive tire wear and excessive stress on the sidewalls, which are the most vulnerable part of a tire.

It is also important from a safety point, to have the psi on both tires on the same axle read the same. The front tires do not have to be the same psi as the rear tires, but both front tires should be approximately the same psi, and both rear tires should be approximately the same. This can be important in control of the car in turns and control of the car in braking.

 

I'll check it out. I know when I'm not filling my tires, I have to drive a bit before the pressures display, but maybe sudden changes can't trigger something too. They must have some strange voodoo at work

 

Like you, every time I stop the car, when I start it up again, I have to drive between 1/4 and 1/2 mile before the psi of all four tires displays on the dash. Maybe you and I are voodoo-free?