what tire pressure should i run in my tires?...i have the stock 17"...AE rims and tires

 

I like 36 psi front and 33 psi rear. Manufacturer specs say 32 all around, but that is too soft if you ask me.

 

I put it up to about 33-34 cold... (all around)


-Tom Z.

 

34 front
35 rear

 

I run 33 all around but have been thinking of going a little higher, maybe 34-35 in the front 33-34 for the rear. Has anybody else noticed that running a higher pressure - say 36 or so - accentuates any balance vibration you have. I have NEVER had a set of tires balanced perfect, even after taking them back a couple times. I just put on the Pilot's and had to take them back to be re-balanced.

 

no funny vibration here

 

Noticed that just 1/2 psi difference between the right and left side tires will result in a shimmy. Car is very sensitive to tire pressure.

 

Go to a place that uses the Hunter GSP9700. They will be balanced perfectly...

 

37 front
35 rear
No more squealing in corners!
I also notice turn-in is much sharper with this pressure.
Max psi is 45 according to stock tires.

 

Don't your a**es hurt with that high pressure?
I use 32 all around, but i am gonna try 34-35 next time becaseu its soft

 

34 lbs all around for me. My car is lowered. I dont want the pressure to be too high because it will stiffen the ride a lil more.

 

nah, my *** has enough padding so I don't beel a thing.

seriously, I believe the suspension has enough damping that the ride doesn't degrade. My wife would let me know if it started riding as harsh as my Mazda. The car seems smoother to me with the tires inflated higher. It also helps that I mainly drive it on smooth roads. And when I go into the hill country 2-lanes I am more worried about the handling than the ride.

 

Wow! I only set it at 32psi. I tried 30 for a while and the tire always looked low but it rode better. I can definitely feel a difference at 32. 37psi must be like rocks!

 

I wish my GLE had the 17" option

 

no vibration here either dude.....

vibration is usually not a good thing.......unless it's coming from the mouth of the woman whose lips are wrapped around your...
finger. I love my girl.

 

I went to the Hunter website and found my Nissan dealer has a GSP9700, I'll probably take it to them when I do A rotate. I should be ready to rotate them the end of January. The web site also mentioned (as someone else did on this thread)that tire pressure effects balance but it didn't say HOW it effected it. I check my tires weekly when cold with a dial guage and keep them right on. A 1/2 lb difference shouldn't cause a vibration should it?

 

The tire pressure on most cars isn't effect as dramatically as the Max SE. I found that as little as little as 1/2psi difference between left and right side tires will somewhat mimick an alignment pull at low speed and a balancing problem at highway speeds. Kinda like a mix of the two. Taken the car back to the shop to recheck balancing and alignment on several occasions, only to find out by myself that these "professionals" seem to be ignorant of tire pressure.

I check my tire pressure every 3 days and adjust to the 1/2psi.

 

Hmm.. i check mines about once a month (or sometimes even less often), and I find that my stock blowtenzas keep impeccable consistancy.. (always the same on all 4 tires!!!)

My digital meter is good to 1/2 psi... (which is good enough for me)


-Tom Z.

 

I doubt you want to change from your stock pressures by more than 3 or 4psi.

One method of setting the pressures is to buy a bottle of white liquid shoe polish - the kind with a foam applicator tip. Put 3 or 4 bands of this white stuff across the tread area of each tire and ALSO down onto the sidewall of the tire.

Now find a big empty parking lot and drive fast enough to get the front tires and then the rear tires, to break loose. Don't do this if you don't know what you are doing! Now look at where the shoe polish (which is really like chalk) has worn off. You only need to look at the loaded tires - if you turned left - then the rights got the abuse. If the chalk is worn off on the sidewalls of the tire, PAST where the tread ends - the pressures are too soft - the tire is bending under because of low pressure. If the chalk is not worn off all the tread area (including the little bit that extends down the sidewall) - the pressures are too high. This is a crude test but about as good as it gets for most.

I've never found more than 3 or 4 psi change from stock is necessary. I refine the test a bit more for myself by actually test driving the vehicle at the limit but I have a facility to use, designed for these purposes. If the rear is light - I up the pressures and same for the front, if that's where it is occurring. I just set up a new Mazda Protege and it amazed me how 3psi in the rear of this car made it go from good to great in handling. My Maxima isn't on the road yet, just bought it (used 2000), and so don't have plates yet, but I'll use the techniques described above.

 

I have a 2k1 Se loaded. I run 40.5 psi in all four tires, It cuts down tire temperature and wear. I regularly drive at high speeds for extended periods of times (I.E. 100-105 for 3+ hrs). The ride isnt too affected by the tire pressure,cause the tires have stif sidewalls. What is affected is turn in (greatly improved). The Maxima has a stiff suspension with relatively no travel. That is the reason for the poor ride over broken pavement.

 

Confusing

Anyone can go fast on a straight line, even Ray Charles. If your pressures are too high, you will be bounced around a great deal more than is necessary on every bump in the road and NOT gain any handling - in fact, loose some. It's not just a simple task to set your tire pressures to some high pressure and assume all is well. Since Maximas aren't raced, we have no body of knowledge to draw upon. I'd stick with factory recommended pressures in the abstance of qualified experts.

Regarding tire temperatures, I'd like to see the pyrometer readings the earlier post suggested you had. E55AMC2 noted HIGH TEMPERATURE READINGS. High tire temperatures, particularily in limited portions of the tread surfaces, imply incorrect pressures. Certainly, reading the temperature of the tire across the tread width, is a more advanced way to set up your tires but other than racers who has a pyrometer ( a temperature reading device for tires). I don't know if the preceeding post really meant to imply he/she had done temperature studies. Please, EMG, post your readings. What were the high readings. What made you settle on your current psi. Thanks. We are lucky to have this information.!!!!!!!!

 

I think the readings were all about 110 - 112 dewgrees across the tread on the fronts, and about 95 on both rears. Also, I can tell they are too hot when i can smell them burning. Since i bumped up the pressure, the burning smell has stopped. As for the bouncing around, i dont really get any. I dont really race my maxima. The High speed is achieved on my way to and from school on the Florida Turnpike. The extra pressure helps with gas mileage too. I noticed about 2 extra mpg at 36psi, and about 3.5 at 40.5.

 

What brand of pyrometer do you use. I always have to borrow a friend's and i'd love to buy one. Give us a quick review of the model and brand you use. How long does it take to get the readings, how confident are you of the section of tread being measured. Maybe the forum can get to the point that the club owns one and we loan it out, with suitable deposit, to other members.. Anyway give us the brand and model and if you could be more exact about tire temps it would be helpful. It's really rare to have even temps across the tread.

 

I never really paid attention to the brand and model. The unit belings to my mechanic, he let me use it when i was there getting routine maintenance. Im not too sure about the readings because i took them after the car had been stationary for about an hour. As to the tire pressure thing, i called tire rack and they told me to use whatever pressure that i see fit. The only thing that i would be hurting by using 40.5 psi is my a$$, so long as as i dont exceed 44psi cold.

 

Tire readings, by pyrometer, are taken HOT, not after an hour. Pyrometer readings are always done after the car has been cornered at maximum and then IMMEDIATELY read. Most typically they are done after some hot laps on a race track.

You can use any pressures you want on your own car but I CERTAINLY WON"T POST THEM!. Your car may handle poorly not only on the track and but also on the road although you may never know how badly it is handling, until the first time you really have to swerve to avoid something or take a corner near the limit. I 'd suggest the Tire Rack is not the ultimate authority on such subjects although they are correct in the fact that you SHOULD NEVER exceed the maximum pressure designated on the sidewall of the tire!

I guess, given what you have said, is that 40.5 lbs is what you use and you are unaware of any negative consequences on your interstate commutes. But it is irresponsible to post such information suggesting this is the optimum pressure. In fact, it seems likely it may hurt people by diminishing the handling and braking capabilities of their cars. Naturally, as you increase pressure there is less wear on the tire. Also there is less area touching the road as the tire ballon so a smaller cross section touches the road. You may get better gas mileage but the handling and braking can be considerably worse, if they are over-inflated.

I certainly don't have all/or any answers regarding tire pressures but I'd hope no one would/should make recommendations based on such limited and flawed information.:

 

Larrfry, i know that youre supposed to take the readings immediately after cornering, but by the time I had remembered to do it, it was too late. I apologize to anyone who read my erroneoulsy collected data. Also, i never said that my pressure was the optimum pressure. In fact, there is no "optimum" pressure. Every driver is different, and the way he/she likes their car to feel is also different. I made the "recommendation" based on my experience with the car and the type of driving that I do. Anyone who wants to modify their car or tires in any way should take the kind of driving and the place in which they do it into consideration before doing anything. Also, NEVER EXCEED THE PRESSURE WRITTEN ON THE SIDEWALLS.

 

Back to Rob's original topic for a sec . . .

I run 36 or so up front and 28 or 29 in the back (cold pressures).

My car normally carries just 2 people and not much heavy stuff in the trunk. So I can get away with setting my rear tire pressure lower than 32 to further dial out some of the OE understeer. More than 37 psi cold up front has not demonstrated enough benefit in my normal driving (which includes hard cornering whenever possible) to be worth doing.

Norm

 

There are two ways to look at understeer. The front tires are doing too much work or the rear tires aren't doing enough. I'D NEVER GO BELOW FACTORY RECOMMENDED PRESSURES. Case in point: The Ford Explorer and Firestone tire debacle. Ford blamed Firestone and Firestone blamed Ford for these tires suddenly failing. Ford probably picked a tire that was marginal for the weight of the vehicle and Firestone pointed out that Ford recommended pressures too low. The bottom line is if pressures are too low you get a lot of "micro-squirm". Meaning the tire is constantly flexing due to under-inflation. This builds up heat and HEAT is a tire's biggest enemy. The faster you go - the more heat that is produced and flex also increases. In the case of Firestone and Ford this produced catastrophic failure. Low pressures (below manufacturer's recommendations) are almost always dangerous.

If you want to dial out understeer (hard to do in a front wheel drive vehicle), you might want to subtly increase rear pressures to make the rears stiffer so they "can do more work" and better balance the fronts. I won't increase them more than 3-4 psi above recommended however. Then, assuming you have the expertise, you can test your results. My best guess is you are going in the wrong direction by softening the rears to combat understeer PLUS you risk delamination by having under-inflated rears. ONE THING I"M SURE ON - NEVER GO BELOW FACTORY PRESSURES.

Please post your results.

 

Forgive the ignorance. So generally:

Fronts:
1) High tire pressure = stiffer ride and better turns, less tire wear
2) Low tire pressure = softer ride, better launches (straight line) and more tire wear

Rear:
1) High tire pressure = helps the stability of the car

Am i right?

 

Generally - NO, NO, and NO --- it's not that simple!

Stick with the recommended tire pressures measured COLD unless you have the expertise to understand the very significant changes you will make to your vehicle by changing from stock pressures.

RE: Your specific questions.

Fronts higher: - stiffer ride - probably yes but you may not feel it

Fronts higher: - better turns - maybe better , maybe worse

Fronts higher: - tire wear - Might be better overall but could be worse on the center of the tread but less on the edges on the tire. The tire wears out in the same amount of time - just unevenly.

Low front tire pressures: - tires could delaminate and you die. Lauches probably worse. Ride - probably softer, tire wear probably greater.


Rear tires - higher: Stability - who knows - maybe better, maybe worse. Uneven wear may increase.

Your ability to brake probably will also change as you vary pressures of the front and rears!!!

In the end, that's why very few should deviate from stock pressures!

 

Thanks for the explanation. I was just curious because some people seem to talk about lowering the front pressure when going to the track. I wasn't so sure what type of performance gains it would have given lower tire pressure (i'd tend to believe) would give better grip when launching really hard. But i also think too low a pressure would be too slow once on a roll.

 

Yes, that's right actually, that lower tire pressures on the powered wheels will supposedly launch better because they're softer and squish down on the road/track more, giving better launch grip. And you're right that there's a limit to this though since there's a point where the heat and rolling resistance get unhealthy.

 

I'd have responded sooner, but the weekend intervened . . .

Over the years I've experimented with tire pressures in all of my cars to suit my preference for less understeer than is present with the factory recommendations, and it's always been done with some correlation to my normally encountered loading condition. Never mind how much time has passed since I last stuffed my car with people needing a ride home from some event.

I clearly identified my usual loading as being substantially lower than the maximum vehicle loading, and implied that it is mostly just 2 front seat passengers. Keep in mind that the OE factory pressures on the decal are what's recommended by the vehicle manufacturer for the fully loaded condition of the vehicle. In other words, it's at best a vehicle max-loading based limitation.

Note that the pressures could actually have been specified by Nissan to ensure a certain minimum amount of understeer, since that's an easier handling trait for the vast majority of drivers to cope with. Those of you with long enough memory may recall that Chevrolet tinkered with the front vs rear tire pressures on the Corvair to keep people out of oversteer (something like 15/28, I think; my uncle had one), so I'm not making this up.

To clarify still further, our 40 lb granddaughter is probably the most frequent backseat passenger. Sure, were I to undertake a trip with 3 adult passengers plus a hundred pounds or so of luggage, I'd add some air to those rear tires. Things like that do occur to me without external reminding . . .

Somewhere I have some tire load vs inflation pressure tables. They're old, but they do give some idea of how fast the load rating drops off with reduced pressure. Reducing the load from the maximum by about 200 lbs per rear tire does allow for a slight reduction in their pressure. As a first approximation, a 200 lb reduction in load for a tire set at a pressure corresponding to a 1400 lb load suggests something in the 27 – 28 psi range as being reasonable. Or I can find those tables or track down newer ones to post hard data from. Too low would be if your actual vehicle load is above the tire load table value for whatever pressure that you've selected.

I know it's difficult to tune out all of the understeer in a FWD car. But it can be minimized.

There's another component of understeer/oversteer, and it has to do with lateral tire stiffness and how it affects drift/slip angle. Dropping rear pressure will cause the rear slip angles to be larger at any given lateral acceleration, which by definition is a reduction in understeer. And you can feel it. Actually, it's possible to get it so loose (with a big enough pressure differential) that you could enter a corner a little hot and find out that either more throttle or less throttle will initiate a spin. By actual test drive (driver only), 36F and 26R in my '87 Max was too getting close to that point for me; backing off to 35/27 was enough to tame it and I eventually settled on 35/28.

I'm aware of the usage of extremely high rear tire pressures in competition as a means of killing understeer by reducing the size of the contact patch when class rules do not permit smaller tires out back. A 4 psi pressure differential won't give you enough to be worth doing. Heard of people running upward of 50 psi in back. But that's a unique situation and a bit removed from street driving (you'd get excessive rear tire center tread wear and wheel hop while cornering or braking if the pavement wasn't racetrack smooth).

Hence my basis for a little more front, a little less rear.

And I'm going to try to stay away from the Ford/Firestone issue (SUV's and tall-profile tires), since there's more going on there vehicle dynamics-wise that will only muddy the issue for sport sedan tire discussions..

Norm

 

You sure you have your info straight? If you increase the rear tire pressure, you create more understeer and not dial it out as you say.

I autocross my Miata so my tire pressure recommendations are worthless for a Maxima due to different center of gravity, weight distribution, and drivetrain configuration. I'd start at 34 front/32 rear and work off of that (higher front than rear should dial out the understeer characteristics of the nose heavy FWD Max)

 

Carried somewhat to extreme, increasing rear tire pressure can do that. See toward the end of my previous post. I know that message is a little on the long side, but it was intended to cover a lot of ground.

And 34/32 won't make much of a difference from the 32/32 that's OE, what with that strut/beam axle configuration and 108" wheelbase.

Norm

 

Excellent article Norm. Clear and technically correct throughout - thanks! [me copies and pastes to text file....]

 

Generally to combate understeer you increase pressures in the front and reduce in the rear, as you suggested.. However, the rears in the Maxima are already low and increasing the fronts may/or may not improve things.

I think, given earlier posts, that increasing rear pressures in a FRONT WHEEL DRIVE VEHICLE, is a trick I learned (unconsciously) from racing buddies. My guess is this - it causes such poor contact with the road, the rear is forced into oversteer.

I still remain firm however - don't go below recommended pressures and until this is a racing only forum - also stick with stock pressures.

 

I blew this with not being clear in my earlier discussions. Understeer - you can combate it with higher front pressures to a point - and after that - it does no good


OK- Understeer: You can lower rear pressures - which is stupid - given the low settings of the Maixima. Tires delaminate due to low pressures.

I've learned , from the track, to really increase the rears, to force oversteer - but you are right - NEVER SHOULD BE DONE FOR THE STREET.

 

F/R 35/32 I have 16's.

 

every tire has a different slip angle. Softer compounds with stiffer sidewalls don't require high tire pressures so a 34/32 combo would be fine. Crappy all-season tires made for Buicks have low slip angles and will not function well at lower tire pressures, as do the crappy tires found on SUV.

To anyone with racing experience, two psi makes a world of a difference when driving at the limit. For most here, they probably wouldn't even notice it, though.