The tire on the driver side front is going flat. does anyone know how many psi should i put in it? thanks

 

I run 32 front and 30 in the back.

 

Look on your tire and use what it recommends...

 

no, that's the max rating the tire can handle. you put in the psi from what the owner's manual shows, not what the tire shows.

 

If you look underneath the lid of your centre console box by your elbow you'll see the tire pressure numbers sticker.

 

Does it say 44 PSI @ X amount of load? Your tires are made for other cars too. You need to take into account of the load. When you over inflat, it could cause tire wear, bubbles or burst at high speed.

 

And why did the tire place inflate them to 40? I only ask because this is the first time I've heard this ......

 

at the recommended tire pressure of the car around 30, it does look a little flat, but i'm pretty sure it's normal. I dunno, anyone care to back me up on this?

 

You don't go by what the tire looks like
at 30 psi. It'll look flat because the car
is at rest and the car's weight is on the tires.
It looks deformed. When you get up to speed
the tire will "expand" to it's proper round shape.
Also, the heat generated will increase the psi
of the tire.
Always go by the vehicle's recommended tire pressure,
not by what it looks like.

 

That's the maximum recommended pressure for the tire. And that is rated at a certain temperature. On a hot day you're risking a blowout. Always go by the sticker on the car or the owner's manual.

Man, your car has to ride like a rock. It must skate over the bumps too.

 

You go by the tire, NOT the car. The reason why is because the Car maker is not going to know the properties of a tire like the tire maker would. 32 PSI for my tires, make them look flat and handle very sloppy. 40 (which is what I run) makes it sit and handle properly. I don't know where you get your info from, but talk to a mechanic........

 

That's right. It's supposed to look kindof low at normal pressure.
What you are referring to as the natural shape of a radial tire. Radials have a bulge at the bottom when inflated properly. That bulge helps the shape of the tire to maximize the contact patch when the tire is being bent out of shape when taking turns. All tires are radials these days. The "old" type tires were straight up and down on the sidewall.

DW

 

Yes, you can go by the tire max psi. The point I'm trying to make is...if the tire says 50 psi max @ X amount of load, it doesn't mean you just pump it up to 50 psi. Ok..lets take this extreme example. A tire has a 50 psi max @ 2000lbs of load. Your car weights at whooping 4000lbs. That's twice of the load. You pump the tires up to 50psi. You are exceeding the max psi!!!! How about this analogy. Blow up a ballon to full. Put your GI Joe on it. Nothing. Put your butt on it. Kaboom. Isn't it the same psi???

You will need to do some math to figure out what the max psi of the tire is for the weight of your car.


[Edited by 1MAX2NV on 01-17-2001 at 01:18 PM]

 

"You go by the tire, NOT the car. The reason why is because the Car maker is not going to know the properties of a tire like the tire maker would. 32 PSI for my tires, make them look flat and handle very sloppy. 40 (which is what I run) makes it sit and handle properly. I don't know where you get your info from, but talk to a mechanic........"

All three of the mechanics and tire shops you spoke to are dead WRONG. I am a mechanic - actually I run a service station that among other things installs thousands of tires a year. Radial tires "bulge" - and low profile tires can look almost flat when properly inflated.

There is a reason there is a pressure sticker on all cars. If it's not there, it was taken off by somebody. If you checked several different cars that take the same OEM tire, you would see that there are different recommended tire pressures. They go by vehicle weight, weight distribution, front or rear wheel drive, the type of vehicle (XJ6 Jags recommend 29 psi for a smooth ride). There is a reason why a Porsche 996 recommends 44 psi on the rear and 36 on the front - because the damned engine is in the back, and that's where all the weight is transferred to under acceleration. However, you might see those same tires used on a BMW at 34 in the rear.

I say again, the pressure rating on the side of the tire is a maximum recommended pressure. And that is cold pressure - it says "cold pressure" on the side of the tire. You what happens when a tire heats up? For every 10 degrees your tire pressure goes up 1 PSI. On a 95 degree day your taking chances running your tires at the pressure stamped on the sidewall. Go to http://www.tirerack.com/tires/tiretech/pressure.htm.

 

I thought you make it a few psi lower then the max on the tire. I had tires that had a max psi of 35, so i put in 30-32. Recently i got tires that had a max of 51 psi. So i thought i should put 42-45 psi. The car rode hard and had bad traction. I asked around and then lowered it back to the recommended 30-32 psi. Now the ride is smooth, the trackion is great, and i didn't loose a tire learning the lesson.

 

Nothing that anyone has said is dead wrong. The recommended inflation pressures are "recommended" not absolutes given by the car manufacturer. I have seen alot of debates on this issue, and it is a fact that there is nothing drastically wrong with putting some extra air in your tires as long as you are still below the maximum recommended "cold pressures" You will most likely not be getting maximum traction in dry weather, but you will gain some in the rain. Your ride will be a bit stiffer, but you might get sharper steering and longer tread life. The list goes on and on, and for most people the manufacturer's recommendations are the safe easy route.

However, CFster may be unintentionally misinforming people by his last statement about cold pressures and temperatures. Try this real life example I recently read about. A husband stopped at a gas station on a hot summer day during a long trip and checked his tire pressures because he remembered that one of his tires was low on air due to a small leak. When he checked the pressure he found that the one that he thought was low on air was actually reading 35psi not the 26psi recommended. Dumfounded, he let the air down to the recommended pressure. 60 miles later, at 75miles an hour the same tire blew out causing the family's Ford Explorer to flip several times. The police investigation determined that the tire blew due to underinflation. Underinflated tires generate much more heat which translates into more tire pressure. Always check your tire pressures cold before driving.

Whew! That was wordy for my first post!

 

for my 98 se with the eagles which has a max psi of 44 what should i put it at? like 36-38? please just straight answer, thanks...only if your sure

 

Honeymooner4evr

That's why I stated that there is a "cold inflation pressure" on the side of the tire. The tire pressure should be checked before the car has been driven or the tire has had a chance to heat up. Overinflating causes the tire to blowout from too much pressure not heat. Though heat can be a cause of overinflation.

I still stand by the vehicle's recommendation tire pressure - that damned sticker is there for a reason.

I'll now shamelessy quote from the Tire Rack installation guide:

"For all vehicles produced since 1968, the original tires sizes and inflation
pressures (including the spare) are listed on a vehicle placard. This placard can be located on:

- The driver-side door or door jamb (Ford vehicles on the rear passenger door jamb).
- Glove box or counsel door.
- Fuel filler door.
- The engine compartment

...If a car's inflation pressure has varied from that which was recommended
by the manufacturer, it's likely that the tire's wear and performance
characteristics have also changed."

It doesn't matter what brand of tire you are putting on - you always go by what the automaker recommends.

Now that said, there are situations where you need to change the recommended pressure. Tire Rack recommends a maximum "competition" tire pressure on a front drive vehicle to be 35 to 45 front and 30 to 40 rear. After which the tire pressure should be returned to normal recommended tire pressure once the car is returned to the street.

Running higher pressure results in less rolling resistance and perhaps sharper steering (though I have found the steering to get lighter - probably because I've lost grip) and the car has a tendancy to "skate" over the bumps. Generally a scary situation which caught me by surprise when I was going down a bumpy off ramp and the rear end started lost grip and eventually came around on me.

By installing a RSB in my Max I have changed the car's handling characteristics from understeer to oversteer. I would like to have it more neutral so I lowered the tire pressure in the back to get more grip. I currently run 34 front 31 rear. It seems to have made a difference. Lower pressure (to a point!) equals more grip.

 

Thanks for your clarification and detailed response. We are on the same page on all of this tire pressure stuff. However, underinflated tires are a major cause of blowouts and tire failures on the road. It is a combination of Physics and Chemistry that explain why a tire heats up really fast and then fails. Alot has to do with the load that is being placed on the tire, but I think that a Maxima owner would rarely have this problem because the load that the tire can carry far exceeds the Gross Vehicle weight that most people are going to carry in their Maximas. Therefore, you have a built in Safety Factor.

Anyway, I hope Kineshi is all clear.

 

I have 34 in the front two tires, and 32 in the rear tires.

 

Agreed. Low pressure is just as bad as too high a pressure.

 

Wow..
40 PSI ??? is this for stock tires? (something with 15' rims)

Because last week i tried to put 34 front 32 rear (usually 31 F and 30R) and it almost make me span out in the corner. Rear tires seems to losing grip and my tires are less than a year (Michelin pilot)

Any opinion?

 

If you have the original OEM tires or replacement tires with the same characteristics, following the manifacturer's recommended tire pressure is the best option. My original tires with a maximum tire pressure of 35psi drove fine when set at 33 front/32 rear. The replacement tires (higher performance Michelins) had a different tire wall stiffness and a maximum tire pressure of 44psi. The new tires were definitely underinflated at the original tire pressure as indicated by worn tire edges after a few thousand miles. Raising the tire pressure to 38psi all around produced much better road behavior, even wear pattern, and better fuel mileage.

 

I have only had my Maxima a thousand miles, but living on twisty back roads the car handles better with a couple psi lower in the rear tires.

 

 

thanks i appreciate the detailed answer

 

I can't believe people seriously think that what is stated on the tire is what you should run.......<shrug> The same logic would dictate that you should always run the engine at redline because that is the maximum. I don't know where you found those "mechanics" you talked to but they must have been rookie tire jockeys at Firestone or smoking something illegal. I am a retired ASE certified Master Technician first off, and I have seen enough BS on tire pressure to drive me crazy. First of all, you can't go by the look of the tire when it's a radial, unless it looks different from the other tires...radials are supposed to bulge out. The Maximum inflation is what the tire will tolerate during mounting and should only be used when mounting, if it is over 40 psi at least(most passenger tires have a max of 35 and many automakers use 35). I'm not Einstein but I'm pretty sure neither Goodyear, Dunlop, Michelin etc..... built their tires specifically for the Maxima or did extensive testing on tire pressure to determine best wear, ride, handling and safety for the car. I am pretty sure however that Nissan did, anyone know who Nissan is? They built this car called the Maxima.....you know, the one most of us drive. The automaker usually errs slightly on the side of comfort so you can safely add a couple PSI for performance but watch the tires for wear. I find that my 98 SE with 225/50 VR16's rides/handles and wears best at 35/34 front and 33/32 rear.

I agree with the tire rack on their pressure for competition but you have to realize that alot of these competitors fill their tires with nitrogen. Nitrogen does not expand like the air we breathe when it is heated thus the tire pressure does not rise much. If you start pumping the tire full of it's maximum of 44 or whatever you will be looking at 50 or so once you get on the road....and that aint so good. A Maxima just isn't heavy enough to make use of more than 35 PSI, any more and you will be riding mostly on the center of the tread. If you found your new tires actually need 38-40 PSI for propper wear it is likely the tire is the wrong size for the rim and the footprint is compromised at normal loads and pressures. I remember working on a car that had come into our shop once, a Honda Prelude with new rims and low profile tires. The owner was upset that the shop had done a crappy job on the balance, I checked the balance and it was within spec, I even went a step farther an balanced them to a finer tolerance than most people get. He came back again, still whining. Same routine, even checked the tires and wheels for runnout and out-of-round....nothing. Then I noticed that the tires had been re-inflated to about 45 PSI, the first time I thought it was a fluke from mounting. I asked the owner and he said that they were suppsed to be inflated to that level. I asked where he got that info and he looked at me like I was crazy and said that it says so on the tire..... It was clear to me that he was an idiot after that point and I refused to work on his car anymore. Of course he wouldn't accept the fact the the car rode fine at the correct PSI. Bear in mind that the tire pressure on this car should be 30-32 and he was running 45.... no wonder it didn't ride right. I can make tons of points here concerning the logic. IE, the car is rated for 5 person occupancy, does that mean you have to put 5 people in the car at all times? Should your temperature gauge be pegged at maximum at all times? Will the car stop running if the fuel tank is not completely full? Get over that silly Max inflation stamp on the tire, they have no idea what service that tire will see when manufacture it. It could be on a 2800 pound passenger car driving grandma to the market or a 4400 pound SUV loaded with 5 people and pulling a trailer to the campground. Should the PSI be the same for both? I hope you say no. Some times you have to trust the automaker's judgement (not in the case of Ford Explorer's with Firestones), they really don't produce the cars to handle poorly, they want people to be happy with them. Stop the insanity!

 

Thanks for reiterating what was stated a few posts ago.

There should be a FAQ on it or something.

 

On my 96 SE, the sticker says 33/32 PSI for F/R. I however have 16x7.5 with 225/50/16 OZ wheels. On OZ's webside, it recommends increasing car manufacturer's recommanded tire pressure by 4.5 to 7.5 PSI when the tire profile ratio is lower than stock (ie from 60 to 50). So what is the propoer tire pressure for my car? I now inflate them at 36 PSI.

 

My mechanic has been an ASE Certified mech for 20 years. He has been a Nissan mech for 10. I trust him without question. Second if everyone is saying you use what the car says to use, then the max cold PSI is onlt 29 psi. Not 32. Which means everyone is overinflating their tires. I set my tires to 32, and 29 and drove them. I will not run them at that pressure anymore. I put it back to 40. at 29, and 32, there is noticable cupping, even after running them to warm them up. At 40 there is none.

And yes, my tires are one size wider than the stock 15"

[Edited by Whitemax on 01-22-2001 at 02:24 PM]

 

If you want to calculate more precisely the tire pressure for your car, check out the thread "Tire pressure again.." in the Yahoo Infiniti owners' club.