Air Down?

[Mannygrover]

I just acquired a set of Pirelli Scorpion tires for my 5th Gen 4Runner, which are rated at 10 ply, and carry 45 Lbs. of pressure, ordinarily. What would be the proper PSI to set them when being Off-Road? I asked Pirelli, but like most, they can't say anything, because we would then become victims of their information, and the Victims would then own their company.

 

[Bama_Kiwi]

My STT Pros are 10-ply and I have had good experience with going down to 18psi.

 

[Mannygrover]

Go Bama,
Thanks, I will give this a whirl, and see what happens.
It sounds like a perfectly rational conclusion, startijng at 45, and all.
Good to have some experienced based stuff to go on.
Excellent.

 

[Bama_Kiwi]

Go Bama,
Thanks, I will give this a whirl, and see what happens.
It sounds like a perfectly rational conclusion, startijng at 45, and all.
Good to have some experienced based stuff to go on.
Excellent.

Also, for what its worth, I only air up to 35psi. Again, no issues.

Good luck and report back with how you go.

 

[diabetiktaco]

Depends on the terrain. Your question is too vague. Soft sand would be 15-18 psi. Washboard road, maybe 22 psi. etc. It also depends on the weight of the vehicle at the time. You can go down as low as 8 safely but you are in bead popping territory there. They won't answer you because they legally can't.

 

[MidOH]

I do the wood 2x4 trick.

 

[Mannygrover]

Depends on the terrain. Your question is too vague. Soft sand would be 15-18 psi. Washboard road, maybe 22 psi. etc. It also depends on the weight of the vehicle at the time. You can go down as low as 8 safely but you are in bead popping territory there. They won't answer you because they legally can't.

Excellent.
I understand and appreciate your comments about context.....and I get it.
I am about to tackle Moab for the first time, so your guidance is fully useful.
I also understand your statement re "They won't answer you because the legally can't".....
I know what you say to be true, but it really rubs me that
that the pesky lawyers have carried it to that extreme.....
all in the unspoken name of their own self-interest, largely disguised.

 

[diabetiktaco]

Excellent.
I understand and appreciate your comments about context.....and I get it.
I am about to tackle Moab for the first time, so your guidance is fully useful.
I also understand your statement re "They won't answer you because the legally can't".....
I know what you say to be true, but it really rubs me that
that the pesky lawyers have carried it to that extreme.....
all in the unspoken name of their own self-interest, largely disguised.

When you are with a group its fully acceptable to ask everyone what they are going to air down to

 

[Mannygrover]

Good to know, thanks.

 

[slomatt]

I just acquired a set of Pirelli Scorpion tires for my 5th Gen 4Runner, which are rated at 10 ply, and carry 45 Lbs. of pressure, ordinarily. What would be the proper PSI to set them when being Off-Road? I asked Pirelli, but like most, they can't say anything, because we would then become victims of their information, and the Victims would then own their company.

There are a lot of variables (sidewall strength, sidewall height, vehicle weight, terrain, etc) so the best bet is to test various pressures and see what works for you. I'd recommend starting in the low 20s and see how that rides. If you need more traction on rocks then you can go lower, but without beadlocks I personally wouldn't go below 15 psi unless I knew my particular rim tire combination was ok at that pressure.

For example, I have 32" tires on both my trucks. The 4Runner has 16" wheels and I can comfortably run 15-18 psi with no issues. The Tacoma has 17" wheels and at ~17psi I lose significant ground clearance and air starts escaping out the bead.

 

[The other Sean]

How did you come to the 45psi daily use pressure? I run E load range on my frontier and run them at 35psi.

With that said, I come down to 20-25 depending on where I am wheeling. 25 for fire road stuff 20 for more sketchy stuff. I've never gone below about 18, never been on the sand with my truck.

 

[BPCLFD]

How did you come to the 45psi daily use pressure? I run E load range on my frontier and run them at 35psi.

With that said, I come down to 20-25 depending on where I am wheeling. 25 for fire road stuff 20 for more sketchy stuff. I've never gone below about 18, never been on the sand with my truck.

I have KM3s and i run them are 44 on the road they roll and feel ok at the pressure. Some people run them up to 65 but you feel everything. The E load 8ply 10ply tires are really made for big truck ie F250 F350 so able to carry double the payloads of my baby Tacoma

 

[Mannygrover]

At the time of the purchase, (Sam's Club,SLC), I was given strict instructions that these tires required this level of pressure on my vehicle.
He Made reference to this being "A true truck tire", ergo, the need for the greater pressure (17" tires).

 

[BPCLFD]

Yep they are made to run higher pressure Kinda the same as MTB tires and road bike tires MTB 25-50 vs road tires 120 its a comfort vs roll resistants game

 

[The other Sean]

I'd still do the chalk test. that's how I came to the 35psi on my Frontier. I've got 55k miles on my E load range Duratracs with even tread all the way across all 4 tires btw....

 

[Trail_pilot]

This really depends on the weight of your vehicle and the height of the sidewall. I used to go to 15 psi when I have near stock size tires but I go between 6-8 psi now that I have taller tires and have been for years now. I would say depending on how fast you plan on traveling you would likely want to go anywhere between 15-20 psi, then again with the traction in Moab ( from what I've heard, I've never been) you can probably get away with airing down less. this of coarse is my opinion and what has worked with my vehicle in the past and will be different with yours.

 

[BPCLFD]

Yes Chalk test is best way to tell for sure

 

[Braflaum]

Is it possible tp explain the chalk test ??

 

[Charles M]

I drop from 50 psi to 20 on my rig and that worked for me in Moab too.

 

[Bama_Kiwi]

Is it possible tp explain the chalk test ??

Essentially, you make note of your tire's current pressure before taking a piece of chalk and coloring in a large swath of tread, from outer edge to inner edge. Then, drive around for a bit. Once stopped, check the chalk patch and look for where the chalk has been rubbed off.

You want as much of the chalk to be evenly rubbed off as possible.