I've looked and I'm tired of looking...What PSI on these Nitrogen filled tires?
 

Rears are 275/35/19 100w Nitto NeoGen's

Fronts are 245/35/19 93w Nitto NeoGen's

Daily driven best tire wear PSI please.

step one- open driver side door
step two- look at the PSI for your car (should be 35 psi)
step three-??????
step four- profit

It doesn't matter whether it's air or nitrogen, PSI is PSI. It does not change. One is just lighter than the other at an equal volume and pressure.

Thanks. Isn't the 35 on the door based on the OEM tires sizes though? Or is it based on the load of the car? I thought it was the oem tire size.

I'm pretty sure tire pressure is car dependent, rather than tire dependent (meaning an altima with the exact same size wheels and tires would have a different ideal psi due to vehicle weight and distribution). Some one correct me if I'm wrong please

Just do 5~8psi less then what is the max rating of the tire

5 less would be 45-46psi

See. I'm just going to do 35 rear and 37 front. Fuc k it.

Ummm, no. They will ride like the wheels on the Flintstone family sedan.

The max rating on the tire is just that, a max pressure at max load. Since the manufacturer didn't make them specificially for the 350Z, that rating has no bearing on what works or is best for your application.

The number on the door plaque is good for 90% of anything we put on our cars (i.e. with low profile, 18/19" diam, 225-275 width, high performance tires). It's a number that balances wear, handling and safety.

That will work fine. I run 36f/34r.

Thanks for the great response!

Someone make a stick or add this to the top 100 questions that you tire PSI is base on your vehicle load.

It's not really based on the load. The weight (load) helps determine the maximum pressure that a tire can safely handle on a particular car. Our cars are so light, we never approach the maximum loading. In theory, that would allow you to run even higher pressures than the one listed on the tire.

Every time I read one of your posts I learn something new! Very informative member!

I agree with Dave. If you go with something close to the OEM pressures (about 35 psi) with 17”, 18”, or 19” wheels; you should be fine (Dave mentions 36F/34R which is perfect).

Some members insist that you must use tables to determine the correct pressure for a specific car, tire brand, and load rating, but that isn’t necessary. The highest pressure you see on these tables for a sports car is 39 psi, and the lowest is 33 psi (both are well within a reasonable margin of error if you simply run 35 psi).

So… you can see that around 35 psi is very good. In fact if you run that pressure consistently, you will probably be better than most drivers (who don’t maintain tires pressures very well and run either way too low or high).

I run nitrogen-filled snow tires on 17” wheels in the winter. I have more consistent results with nitrogen in my very cold climate (often going to -20F in the winter).

During the summer months, I run summer performance tires with plain air since I’m constantly adjusting the pressures. Low profile summer performance tires heat significantly and you need to be vigilant when maintaining pressures. These tires are very expensive, and you can ruin them quickly if you don’t maintain the correct pressures. You should use a good instrument to check these tires on a regular basis.

--Spike

Spike, Z04 - you just can't admit being wrong can you! :icon18: And there is a significant difference in performance between 35psi and 39psi - any reasonably good driver can tell that.

If anything is going to be made a sticky, it should be the CORRECT method. I laid this out in another thread but for some reason, people won't believe a tire engineer on how to correctly inflate tires :rolleyes:

Anyways, this is how you correctly determine what pressures to run, and not only do I know this because I am a tire engineer, but it is published evvverywhere (here for example: http://www.tiresafety.com/images/Tir...t%20Manual.pdf, page 22). You do not need the load tables for this - you only need to take 10mins and visit a good tire store and they can do it for you.

Stock front tires on my car: 245/40R18 RE050A. Load rating = 93
My front winter tires: 225/45R18 Blizzak LM25. Load rating = 95 XL

The XL is important because it represents a whole different set of loads. It is a "reinforced" tire.

Step 1
Look up load tables I have mentioned (I looked up the ETRTO tables at work today to give this example) and see what the max load is for a 93 load rating at stock pressure (Stock pressure ~35psi). The table says 630kg.

Step 2
Go to the XL load tables (because the new tire is XL rated) and look up the pressure that corresponds to 95 (for the Blizzak) and 630kg (the load from before). The pressure for the Blizzak is 38psi.

Summary
The Blizzak needs to be inflated to 38psi in order to carry the same load the stock RE050As can carry at 35psi.

Now I did this again for the RE-11 tires I just bought, which are 245/40R18 and 97 XL load rating. The pressure for the RE-11 is 35psi.

So, as I said before, the correct pressure does not just depend on vehicle weight - it also depends on tire size, load rating, construction (XL). Sometimes it could be the same as stock, and sometimes it can be different. You should not just assume OE tire pressures, and you cannot guess this by looking at tire wear.

This is not just different because I compared a snow tire with a summer tire. The Michelin PS2 would also have to be run at 38psi (same as the blizzak) for example.

If anyone has any further questions please PM me!

Jeez… :eek: my nemesis is back… like a bad dream (I’m kidding of course).

Re:> Spike, Z04 - you just can't admit being wrong can you!
I’m occasionally wrong, but never in doubt. I do accept correction and always admit error.
________

Truthfully, I cannot detect the difference when running 35 psi vs. 39 psi on summer performance tires (or even on my studless snow tires for that matter).

I must be a moron :o, but the hard compound used in summer performance tires seems to mask this difference. I determine the correct psi using my tire pressure instrument to provide best running on the tire.

I’ve said this before: “Leave it to an engineer to add unnecessary complication to a simple issue.”

Go with 34-36 psi, and you will be fine. If you want to “fine tune,” use the tables, but you won’t see much difference. A better way to “fine tune” is going with instinct, tire wear, experience, and driving preferences. But... for the Z... stay close to 36 psi.

--Spike

the lable is based on the load of the car. my car was 35 psi but when i got my LMGT-4 it was suggested i drop to 34 psi since i had the 17" wheels OEM. i say if you stay with 34-36 psi you should be fine

please stop over analyzing stuff. Nissan uses those industry standards to determine the correct PSI for their cars. that being said all of that fluff you keep spouting has nothing what he should put into his car and just s confuses people. especially when you start comparing car tires to SUV and winter use tires.

maybe as a "tire engineer for bridgestone" you should focus on designing tires that don't feather after a few thousand miles.

Air is 72% nitrogen. There should be no difference.