lightonthehill

Back in a much earlier post in this thread (4:15 PM Sept 25th) I told how I measure and record the tread depth of each groove across the tread of each tire about every three months. If the tire is wearing quicker in the center, I reduce the psi. If the tire is wearing quicker on the outer edges, I raise the psi. This is actually the 'controlling factor' for me. I use the tire wear pattern to determine the psi I run.

Using this method, the psi will be different for different driving styles. Those drivers doing mostly freeway driving may need to go down to 33 or 34 psi. I do a lot of turning and driving on local streets and back roads, which tends to wear the edges more than the center. My optimum psi seems to be around 35, but I have 37 at the moment because the temp is predicted to take a major drop here beginning tonight. Yesterday's psi of 37 will read 35 by daybreak this morning.

Yes, I am **** about my psi. But it pays off in getting the most tire life possible from each tire.

jcalabria

I have found, for me, that 35-36 front / 32-33 rear has given perfectly even tire wear in virtually all of the front drive sedans I have owned (and firms up steering response to boot). Those pressures are typically at or just below the manufacturers recommended high speed/high load pressures, so its not really going out on a limb at all.

Kryogen

Nissan recommends 32, they have probably tested it all, so I run 32. Why bother.

jcalabria

Lotsa reasons...

• Better handling/steering feel
• Reduced tramlining
• Less vibration (higher pressure evens out sidewall stiffness variations, the type of vibration that road-force balancing is designed to reduce)
• Better tire wear
• Better rim protection from potholes
• Lower heat build-up

Besides, 32 is not necessarily the recommended pressure... for the 6G SE it's as high as 38psi:

tejstar01

For front wheel drive cars I have always run the front tires 2psi higher than the rears. This seems to be the best for handling since you don't want the rearend bouncing around since its lighter in the back. Also you can easily rung 36 to 37psi in the fronts, this will give you better gas mileage and will also give you better tire wear, your tires WILL last longer since there is less rolling resistance.

lightonthehill

I agree completely with jcalabria and tejstar01. Most of the weight of the Maxima is on the front tires, which do all of the accelleration, most of the braking, and virtually all the steering. A couple extra pounds up front actually results in the front tires having the same profile as the rear tires (which are bearing considerably less weight) while driving.

jcalabria

These are very front-heavy vehicles - According to the C&D road test measurements, 62% of the 7G Maxima's 3669 lbs is on the front wheels. That's 1130.5 lbs per front wheel and only 704 lbs per rear wheel. No need for as much pressure in the rear.

smarty666

I'm not sure, for the 7th Gen, non sport package models, the recommended cold tire pressure all the way around is 33 PSI cold! I have been keeping all four tires at 34 PSI cold since I have had the car.

What I want to know is, is it best to keep all four tires at the same pressure as the sticker suggests or should I put 1 or 2 PSI more in the fronts than in the rears, maybe like 34 PSI fronts cold and 33 PSI rears cold???

lightonthehill

You should be fine either way. One problem with carrying a higher psi in the front tires is that all four tires have to have their psi adjusted every time the tires are rotated. As a result, I just keep mine all at the same psi.

It is fine to carry 33 psi per the manufacturer's label, but I find I get more even tire wear carrying a few pounds more. I am currently carrying 36 psi, which gives a slightly firmer ride than 33, and slightly better control.

But four time a year, I measure the tread depth in each groove on each tire, and if I find the grooves in the center of the tire are getting less-deep than the grooves on the shoulder (center is wearing faster), I will drop the psi to 35, or even 34. By this 'tread management' process, I am able to have my tires wear out evenly across the surface of the tread (hence maximize tire life).

The reason tire wear varies for each car is because each car is driven under different conditions. All else being equal, a car that does mostly freeway driving will usually have the center of the tread wearing faster, while a car doing local driving with lots of turns will usually have the shoulders of the tread wearing faster.

smarty666

all good points light! as I said before, I usually keep the pressure 1-2 PSI above recommended so right now I keep it at 34 PSI all the way around. I've tried 36 but the ride beginning to get a little bit to rough for me once they warm up so 34-35 PSI is typically good for me with the ride quality once they are warmed!

Norm Peterson

It ultimately comes down to what you want to get from your car that a little tinkering with tire pressures can provide. Then it becomes the compromise that suits you, rather than the one that Nissan is comfortable about officially suggesting. Corner weight with the car as actually driven, ride & handling preferences, fuel economy, and tire wear rates (and evenness, again relative to just how the car is driven) are the important ones. Slightly separate is the case of unusually low profile tires, where an extra psi or three can help protect expen$ive rim$.

Handling behavior tends to shift slightly as the tires themselves age. If you drive really hard, you might find that the handling "loosens" as the tires approach the end of their life (which if you're driving that hard may not necessarily be indicated by treadwear measurements, BTW). "Loosens", as used here, is circle track terminology covering anything from "less understeer" to "more oversteer".

33 psi all around, at least for that particular tire make/model/size on the non-Sport Package models is where Nissan feels its priorities are best satisfied. It's set more for the average driver who pretty much just gets in and points his car down the road, with unknown vehicle loading (but which is probably presumed to be at or near the max rated vehicle loading), than for those drivers among us who are sufficiently interested in it all to try to find a compromise that's more to their individual liking.

My take on mfr-listed tire pressures has always presumed them to be slightly "conservative" as seen from the point of view of somebody who tends to drive the corners fairly "hard" and prefers firm feel, snappier turn-in response, and a little less understeer. A mfr-recommended inflation pressure set a little too high at either end of the car runs the risk of alienating owners who place greater priority on a softish ride quality, which can have adverse consequences on future model sales. As far as providing cars to drivers of unknown awareness and skill levels, it's probably better in most cases to provide just a little more understeer than to dial some of it out. The harder drivers among us tend to add pressure in most cases rather than remove it, anyway. Yes, there are exceptions.

I have seen mfrs officially recommend more than one set of inflation pressures, and where the "stagger" between front and rear tire pressures also varied in accordance with vehicle loading. At least two of my own cars are included, one of which spec's an unusually high front to rear difference (6 psi, IIRC) under at least one of the conditions.


Smarty – do take a little time with this. Decide which criteria are more important to you and the way that you individually drive. And don't be surprised if what you settle on today might not be what you prefer a year from now.


Norm

vancitymax

They guy at the dealership said It should be inflated to whatever the tire wall says... otherwise you will lose in gas mileage... Maybe there IS a reason y everytime I take it in for service my tires always sitting at around 34psi... hmmm

Norm Peterson

That guy at that dealership is wrong, WRONG, WRONG. He's got scare tactics and hypermiling on his brain (and apparently not a lot of room left over inside there for much else).

The pressure molded into a tire's sidewall represents the safe inflation pressure limit for that tire. This has nothing to do with what vehicle that it is going to be fitted to.

Your starting point should be the car mfr's sticker pressures to maybe a couple psi or so more.


Norm

lightonthehill

NORM IS ABSOLUTELY CORRECT. THERE IS NO FUZZY AREA HERE.

The psi stamped into the tire wall is a safety number showing the maximum pressure the tire can hold without risk of distortion, disintegration or even exploding. Actually carrying that pressure would give terrible and dangerous driving characteristics in many ways.

PLEASE NEVER CARRY THE PSI STAMPED ON A TIRE WALL UNLESS the tire is on the back of a truck, you are going to be carrying far more than the stated load limit for that truck, doing it at a reduced, safe speed, and will reduce the psi to the proper level as soon as the load has been removed.

As far as the guy at the dealership saying that, he is an ignorant fool, and I would have no problem telling him that to his face. The dealer could be held legally liable for any resulting accident. You would be wise to relay this information to your service manager.

LtLeary

I would feel comfortable advising the guy at the dealership to consider a new line of work that won't get people killed or injured. This is unconscionable.

smarty666

Absolutely agree with Leary and Light on this one. The guys at the dealerships are 100% wrong on this and every single car dealerships, regardless of manufacturer, has this idiotic philosophy. That is one of the things I dread when ever I have to go into the dealership for anything. Nissan, Infiniti, and even Acura are all guilty of over inflating the tires to ridiculous PSIs!

For example, one time, there was voluntary recall on the headlights on my FX35. I took it into my local Infiniti dealer for the recall and they said that for free they do a quick inspection on everything because I was around 30k miles at the time of the recall so I said okay. I even told the service advisor to tell the technician to LEAVE THE TIRE PRESSURES ALONE to where I had them at. Well of course, they do the recall and inspection and everything checked out so I took the FX home. On the way home, I noticed the ride was even more choppier than usual. I got home, let the car sit for a few hours and measured the pressure. The tires were at 42 PSI cold! I was pissed as hell. I had to put it all back down the next morning to the 34 PSI cold they were supposed to be at.

For some reason the dealerships think that the tires need to be at 40 PSI +. What they don't get is that the tires are so hard at those pressures that the ride becomes brutal.

Next time Nissan, Infiniti, Acura, or anyone else does that, I'm taking the car back and they are going to deflate them so that I don't have to bend over and break my back to do it myself!

smarty666

Light, I'm having trouble with my TL and uneven tire wear. I had a mis-alignment which got corrected but the tires are still wearing uneven. The door sills says the fronts should be 33 PSI cold and rears 32 PSI cold. I've been keeping the tires at 34 PSI fronts, 33 PSI rears cold. Based on what you mentioned above, could the difference recommended in pressure between the fronts and rears be causing some of my uneven tread wear problems?

Do you think I might be better to keep them 34 PSIs all the way around??

Max Gluteus

With tire pressures so specific for the particular ride style etc what type gauge is everyone using? I have a basic one and don't believe it is accurate enough to tell me the difference between, say 33 and 34 pounds.
Thanks

lightonthehill

smarty - The type of wear affected by psi is the ratio of wear in the MIDDLE of the tread to the wear on the SHOULDERS of the tread. If the psi is high, the MIDDLE wears out first, and if the psi is low, the SHOULDER wears out first. Varying the psi between the front and rear tires by several pounds should have absolutely nothing to do with IRREGULAR circumferential tire wear (cupping, feathering, etc).

If you are getting IRREGULAR wear around the circumference of the tire, your have either an alignment problem, worn suspension parts (unlikely on a fairly new car), or bad wheels or tires. You got your alignment adjusted, but the alignment correction can't undo the irregular wear already put on the tires when the alignment was bad, so it may be difficult to know right away if your newly-corrected alignment is fine or not.

As for psi, you should be very fine with either of the two setups you mentioned, and whether you keep all four the same psi, or have an additional pound or two in front should have zero to do with irregular circumferential tire wear (such as 'cupping', 'feathering', etc).

My best guess is that, either the irregular wear you are seeing was actually done before your alignment correction, or the alignment correction was not done properly. If the tread wear gradually begins to look more even over the next few thousand miles, then the damage probably happened before your alignment correction.

Norm Peterson

I've got a couple of dial gauges that get the most use. A little digital pencil gauge that I use once in a while. And a few cheapie pencil gauges. Not every gauge can reach every valve stem through the various spoke designs.

There's a certain amount of "disagreement" among them all - amounting to a psi or so even between the two dial gauges.

Best way to deal with this kind of uncertainty that I know of is to stick with one gauge and experiment with the pressures a little (without fixating on any particular numbers) until YOU are happy with the handling and ride quality. Longer term, keep an eye on the evenness of treadwear as urged by light. Baseline any new gauge for this car (or any other car, for that matter) against this gauge.


Norm

Norm Peterson

Can you describe the wear in a little more detail? Which tire(s) were involved (and where they were previously located, if they were rotated) matters.

It would also help if you could describe your driving, particularly with respect to how hard you take corners and use the brakes. Do you power out of turns or wait until the vehicle is straight before adding much throttle?


Did you get a print-out of the alignment (as found), together with as-corrected?

How does it "feel" to drive now, compared to before having the alignment reset?


Norm

LtLeary

If you could snap a picture of the uneven wear, I'm sure we could help "diagnose" the potential issues.

cmmetcalf

Put Michelin Pilot 235/55 ZR18 MXV4s on before delivery. I have 15K on them running with Nitrogen at 33 Front and 31 Rear. Wear is absolutely even. I rotate and rebalance every 5k.

lightonthehill

Very unusual to see someone put taller, narrower tires than OEM on a Maxima. Those would not be the tires for maximizing slalom times, but will give a more comfortable ride than the OEMs, do better in inclimate weather than the OEMs, and should have a measurably higher tread life than the OEMs. Your setup will be interesting to follow; keep us informed.

bk2k3max

the safe and recommended settings for our cars is 33 so that's what i would run unless I was going to the race track or something then I'd lower it to around 22/21 psi.

If you are not running the stock tires and rims then I'd say go with whatever was recommended by the manufacturer of the tires/rims you have says to go with but remember that ride quality is the issue that matters with Nissan when building their stock cars so they aren't concerned with each individual's level of sport, ride or handling capabilities or quality, they just do what best suits their intent of what they wanted their cars to represent.

Norm Peterson

You must be talking about racing in straight lines only, because if you ran that much car on tires with pressures that low on my kind of "track", you'd likely peel the outside bead loose and dig the wheel itself into the pavement.


Rims (wheels, actually) have a load rating rather than a pressure rating.

One more time . . . tire mfrs do not establish the pressures that you should run the tires on your vehicle at (or use as a starting point for tweaking your own pressures). At best, they'll look up the vehicle mfr's recommendation in a database.

If you're running tires of different size than one of the OE sizes, you'll need to make sure that the tire mfr's representative is aware of exactly what tire size you're dealing with and the specific vehicle that they're going on. Then ask him to describe how he came up with whatever numbers he gave you, and make sure that his reasoning makes sense at least from a load capacity point of view. Otherwise, how would you have any confidence that his reply is correct? It doesn't hurt to be a little skeptical here. (Hint: there are tables for tire load rating vs inflation pressure)


Norm