Recommended PSI

[IN$EAM]

I have recently wrapped some Viper Reps in Nitto NT420S 265/35R22 (front) and 295/30R22 (rear). The tire pressure upon arrival was about 33 PSI. When I threw them on on the car they looked like they could stand another 4-5 PSI....it just looked LOW. A few of my buddies also thought they looked low. I contacted Nitto and they said I should be running 30 PSI in front and rear. I don't mean to undermine the vendor's input but I can't imagine dropping the pressure to 30.

I have a buddy who is getting a pyrometer for his M3 track days so we will see what the optimum pressure turns out to be.

Just wondering what other people think about this who might be running the same size tires.

[310SXT]

I run about 36-38 PSI in the 265/35R22 tire size, Viper Reps as well. Definitely firmer, but I like it. I'm on the Nexen Roadians HPs.

Good luck!

-310SXT

[IN$EAM]

I run about 36-38 PSI in the 265/35R22 tire size, Viper Reps as well. Definitely firmer, but I like it. I'm on the Nexen Roadians HPs.

Good luck!

-310SXT

Thanks for the feedback. That's about what I'm running now...36...and it seems pretty good.

[JTSRT8]

I have stock sizes, & run 34/33 cold. When the car heats up & it's hot outside I get anywhere from 36/35, to 38/37. I run the fronts 1 psi higher.

[Montreal300]

I have recently wrapped some Viper Reps in Nitto NT420S 265/35R22 (front) and 295/30R22 (rear). The tire pressure upon arrival was about 33 PSI. When I threw them on on the car they looked like they could stand another 4-5 PSI....it just looked LOW. A few of my buddies also thought they looked low. I contacted Nitto and they said I should be running 30 PSI in front and rear. I don't mean to undermine the vendor's input but I can't imagine dropping the pressure to 30.

I have a buddy who is getting a pyrometer for his M3 track days so we will see what the optimum pressure turns out to be.


Just wondering what other people think about this who might be running the same size tires.

That's a damn good idea! I'm going to take a crack at it with an IR temperature gun to see if my 32 psi on 255/20 Nittos is right. I know the tread wear is good at that pressure but it would be nice to back that up against the head cases who run tires at "rated pressure". Let us know how your temperatures work out.

[Teletran-01]

...I can't imagine dropping the pressure to 30.

That's what I keep my tires at. Been two summers and no issues so far.

[IN$EAM]

That's a damn good idea! I'm going to take a crack at it with an IR temperature gun to see if my 32 psi on 255/20 Nittos is right. I know the tread wear is good at that pressure but it would be nice to back that up against the head cases who run tires at "rated pressure". Let us know how your temperatures work out.

Keep you posted.

[IN$EAM]

That's what I keep my tires at. Been two summers and no issues so far.

Hmmm...OK. Thanks for the feedback. Its hard to disregard the vendor's recommendations and also when you hear the same info from someone else running the same size tires. Not only do I want to ensure I have proper tread wear but I have a major concern for the ridiculous amount of pot holes in Boston.

[Teletran-01]

...I have a major concern for the ridiculous amount of pot holes in Boston.

Same here, I had posted these pics a while ago for a different thread. Things didn't get better since. This is Montreal:

[IN$EAM]

Same here, I had posted these pics a while ago for a different thread. Things didn't get better since. This is Montreal:

So if you're running at 30 have you had any problems? Doesn't sound like it but...I'm still skeptical at that PSI and i can't shake it off.

[TK Charger]

just follow whats on your door and run higher if you feel like it.
i wouldnt however recommend going at a lower psi than whats on the door

[IN$EAM]

just follow whats on your door and run higher if you feel like it.
i wouldnt however recommend going at a lower psi than whats on the door

Touche. I guess i was concerned that the pressure ratings on the door were for stock wheels and tires only. Is it weird to exhaust yourself on your own question? I think I'll run what I'm running and let the pyrometer do the rest.

Thanks for the responses. goooooooooooooooOOOOOOO TEAM!

[Teletran-01]

So if you're running at 30 have you had any problems? Doesn't sound like it but...I'm still skeptical at that PSI and i can't shake it off.

Nope, no problems. Try it for yourself and see how you like it.

[IN$EAM]

PYROMETER RESULTS ARE IN!!

Here's the skinny:

Air temp=72
rear tire (295/30R22) PSI=38
front tire (265/35R22) PSI=36

We ran the highway for about 15 minutes at 75-80 mph and pulled off to a gas station parking lot and took some temps (about 8 or 9 minutes after parking).

We took measurements at 4 places across the width of the tread starting at the outside and moving towards the inside:

Both REAR tires: 90, 92, 96, 98
Both FRONT tires: 89 all the way across

So what this tells us (we think) is that the front PSI is fine at 36 with even tread wear. The rear however, looks like it may need to be some camber adjustment.

Here is my concern:

About 3 months ago I had an alignment done by the dealer with my stock wheels and snow tires (i never got before or after readings from them....stupid me for not asking) and I have BCR suspension setup. As soon as spring rolled around and I started running the 22 Viper reps, when you stand back you can definitely see some negative camber. Since the pyrometer checks have revealed that wider rear tires are running hotter on the inside, we are assuming this is due to the factory camber setup for a stock tire and it's punishing the inside portion of the tread. They are brand new Nitto's and i don't wanna run tires bald on the inside by summer's end.

Here are my questions:

- Does anyone know how much of a PIA it is to adjust the camber?
- Is it possible to make a big enough adjustment to correct to problem or will i have to add camber plates to allow for more adjustment?
- Does anyone know a suspension expert in the New England area who help me out?
- Is there something else to look at and maybe we're barking up the wrong tree?

Thoughts?

[willy723]

It doesn't sound like your camber is that far out, and with a bit lower of a PSI in the rears your tread wear should remain pretty even, and as I posted in the "Directional Tire" thread, at the end of the season, if you have a winter setup being in the NE, have the rear tires at least remounted and balanced turning them around so that the inside left becomes the outside right and vice versa for the next season.