Correct PSI for 20" Sport Wheels on M35h?

[mrjarhead]

Hi everyone, so I am putting the stock M37 Sport 20 inch rims on my m35h, with original size 245 40-20 tires. I'm running them at 36 PSI right now simply because that's what the regular tires were at. What is the correct PSI I should be running?

Stock M37 PSI is 33 front and rear for both the original tires as well as the 20in sport option.
Stock M35h PSI with stock 245 50 r18 is 36 front and rear.

M35h GAWR 2486 front
2804 rear

Thanks!

[EdBwoy]

The fastest most certain way to know what pressure your particular car should run from factory is checking the "Tire and loading information" sticker on your door jamb.
Open your driver door and standing outside, face the driver seat/ B pillar. You should see a sticker with a tire on it.

That's what the manufacturer designates based on your wheels/ tires/ body weight etc... And it might or might not change between models. I don't have the literature to confirm right now, but your 36 psi should be fine.

Stray from the OEM spec as much as you need for comfort, mpg etc... as long as you don't exceed the tire safety rating or cause accelerated wear.

[GMBQ70]

In my opinion it’s whatever your preferences are. Stiffer ride vs softer ride, handling etc.
I’m running the same size you referenced and I run mine at 36 PSI.
As you referenced, the door jam is 33 PSI, but depending the tire brand, the max pressure could be up to 50 PSI.
I played around with different pressures until I was happy with the overall ride quality etc.
Hope this helps you out.

[mrjarhead]

The fastest most certain way to know what pressure your particular car should run from factory is checking the "Tire and loading information" sticker on your door jamb.
Open your driver door and standing outside, face the driver seat/ B pillar. You should see a sticker with a tire on it.

Thats what the manufacturer designates based on your wheels/ tires/ body weight etc... And it might or might not change between models. I don't have the literature to confirm right now, but your 36 psi should be fine.

Stray from the OEM spec as much as you need for comfort, mpg etc... as long as you don't exceed the tire safety rating or cause accelerated wear.

Thanks. Actually I am referring to what is not on the factory sticker - the factory 20 inch M37/M56/Q70 sport wheels were not available for the M35h so there is no recommended PSI on the sticker or in Infiniti literature.

M35h uprated the PSI to 36 from 33 for M37, on the stock 18 inch tires, to compensate for the extra 2-300 lbs weight penalty for the hybrid system.

So what I'm asking is what PSI to run factory 20s at to have the same loading, since the hybrids with the 20s is not an official factory combo.

It's why I gave the GAWR numbers

[mrjarhead]

In my opinion it’s whatever your preferences are. Stiffer ride vs softer ride, handling etc.
I’m running the same size you referenced and I run mine at 36 PSI.
As you referenced, the door jam is 33 PSI, but depending the tire brand, the max pressure could be up to 50 PSI.
I played around with different pressures until I was happy with the overall ride quality etc.
Hope this helps you out.

Door jamb for M35h for stock 18s (no other sizes supported) is 36, 33 is the door jamb PSI for all tire size variants for M37.

So they're both Y51s but different weight and loadings.

[EdBwoy]

Understood. In that case, I'd do as GMBQ70 suggested and go with what feels right to you.
I don't think most of us on the forum can calculate exactly what target Infiniti was going for.

For instance, as you mention, all gasoline Y51s regardless of engine size and AWD/ RWD configuration or even packages, were spec'd for 33 psi for the regular road wheels (both 18" and 20"). And that is a fairly wide range of weight throughout the years.
M56 GAWR - 2596 lbs front, 2641 lbs rear... a little heavier than the hybrid, and it's still rated for 33 psi.

... or just go with 36 psi, because that is what they wanted for the hybrid. The tire can handle it.

[Mjkkb2]

I think there's an argument to be made for anywhere between 32 -36 PSI in your case. I'd go with 36PSI personally, but anything within this range should be a correct setup IMHO.

[Ilya]

I try to keep my tires, regardless of size or rim size, around 35psi. Have done so for a decade.

[Purenv]

The M35H with a 20" wheel should be ran at the same air pressure level as the stock 18" as a starting point and adjust up as needed but don't exceed the tire manufacturer's max pressure rating.
Tire pressure is not controlled by the size of the rim but the wieght and dynamics of the vehicle. The reason I stated to not go under the stock pressure(36PSI) is because that is what Infiniti suggests for that vehicle as a minimum due to the added weight. I went from the stock 245/50r 18" wheel to a 285/35r 20" wheel/tire and started at 33PSI and now run them at 36PSI.