Maybe Stupid Inflation Question ...

[Steppenwolf]

Rubi with the Wildpeak ATs ...

What cold psi are you guys airing the Wildpeaks to for driving on city streets and freeways - basically around town, not off-roading?

My sales guy said cold 38lbs psi was 'optimum' for both on- and off-road usage.

But after driving for a while, where the tire mode indicator showed a psi as high as 40lbs, setting them at a cold 38 psi seemed at bit high. Going by feel, I guess.

Seems to me it should be lower. Just looking for input from the tire experts.

Thanks!

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[Whiplash2130]

Rubi with the Wildpeak ATs ...

What cold psi are you guys airing the Wildpeaks to for driving on city streets and freeways - basically around town, not off-roading?

My sales guy said cold 38lbs psi was 'optimum' for both on- and off-road usage.

But after driving for a while, where the tire mode indicator showed a psi as high as 40lbs, setting them at a cold 38 psi seemed at bit high. Going by feel, I guess.

Seems to me it should be lower. Just looking for input from the tire experts.

Thanks!

I run my 315x70x17’ Wildpeak,’s at 34 cold. They run up to 38 or 39 psi hot. They feel great!

 

[Mkcagle]

Set mine cold at 33, at running temps the get to 37/39.

 

[ShadowsPapa]

I think whiplash is in the ballpark - something for ya to try.
My OVERLAND has slightly smaller tires, slightly more narrow. They are great at 38.
But a bit larger and with a larger footprint, 38 would seem too high for your tires.
What's the door jamb sticker say?
When I get my Rubicon take-offs my plan is to start at about 34 and go from there.
If 38 is right for my more narrow tires, it should be too much for yours.

 

[Keller]

I run mine at 35 cold. There are people on this forum that run them lower than that though.

 

[bgenlvtex]

35, pressures are always measured and set cold

 

[Steppenwolf]

I think whiplash is in the ballpark - something for ya to try.
My OVERLAND has slightly smaller tires, slightly more narrow. They are great at 38.
But a bit larger and with a larger footprint, 38 would seem too high for your tires.
What's the door jamb sticker say?
When I get my Rubicon take-offs my plan is to start at about 34 and go from there.
If 38 is right for my more narrow tires, it should be too much for yours.

I'll double check the door sticker, but I thought it said 37.

 

[ShadowsPapa]

A Rubicon is heavier than an Overland so what I plan on doing shouldn't influence what a Rubicon owner does necessarily.
I've found the best advice is the tire maker's settings. They are responsible for the tire not blowing out, sidewalls lasting, and the safety of the tire. What an owner does aside from that is up to them and on them.
I've rarely seen a dealer give great inflation advice. I'm sure some do - but good grief, if the door sticker is 37 why is a dealer suggesting to go OVER that...........

 

[Papa_smurf]

33

 

[Texops]

I have 285/75/17 Nitto ridgid grapplers the sidewalls are stiff. I did a chalk test & 32 psi cold is perfect. I’ve put 8,000 miles on them & wear is perfect.

 

[Bbannongmu]

I have 285/75/17 Nitto ridgid grapplers the sidewalls are stiff. I did a chalk test & 32 psi cold is perfect. I’ve put 8,000 miles on them & wear is perfect.

I was going to say- try chalking them and do a seat of the pants comparison

 

[biplaneguy]

What is Jeep's recommended pressure for the stock Mojave with the 285/70R17 tires?

 

[Zachanadandy]

A Rubicon is heavier than an Overland so what I plan on doing shouldn't influence what a Rubicon owner does necessarily.
I've found the best advice is the tire maker's settings. They are responsible for the tire not blowing out, sidewalls lasting, and the safety of the tire. What an owner does aside from that is up to them and on them.
I've rarely seen a dealer give great inflation advice. I'm sure some do - but good grief, if the door sticker is 37 why is a dealer suggesting to go OVER that...........

Where are you getting your "tire makers settings"? Did a quick search of falken and for any size tire they sell a per tire load of 2klbs or less doesn't require more than 35psi period. Furthermore if you look at the next column increasing psi by 5 to 40psi increases load carrying capacity by 90 pounds. Logic tells me that decreasing 5 pounds should equate to 90lbs less capacity. That tells me 30psi is plenty of load carrying capacity for my 5600lb gladiator.

Edit, I scrolled down to the "floatation" tire sizes and 37x12.50r17 are rated for 2150lbs at 25psi. I guess the manufacturer agrees with us "some guy on the internet" types that have been trying to tell people to quit running high psi and complaining about poor handling and rough ride for decades? Looks like for a 33" on a gladiator you should probably run 30psi and 35-37's you're better off closer to 25psi, per the tire maker of course.

 

[ShadowsPapa]

Where are you getting your "tire makers settings"?

I talked directly to a "consumer engineer" at General. They asked the weight of the truck, tire sizes, load rating I was looking at and so on, what the original tire size was and the factory numbers for those, and he calculated from there. So far, perfect wear, great traction........... Couldn't be happier. Ride is decent, they aren't over-inflated and wear like they aren't underinflated.

The idea I was given was that you change psi to keep the same "footprint" - the same amount of rubber on the road as the load changes.

 

[Zachanadandy]

I talked directly to a "consumer engineer" at General. They asked the weight of the truck, tire sizes, load rating I was looking at and so on, what the original tire size was and the factory numbers for those, and he calculated from there. So far, perfect wear, great traction........... Couldn't be happier. Ride is decent, they aren't over-inflated and wear like they aren't underinflated.

The idea I was given was that you change psi to keep the same "footprint" - the same amount of rubber on the road as the load changes.

I agree to a point, but when we go to a much larger tire that kinda goes out the window. I still can't believe our JLUR with XR came from the dealer at 40 psi. I get good wear and even tread footprint on the 37s at 25psi cold. They are so large they get up to 28-29psi on a long road trip when they get warm. Of course that's a huge E rated mt so it's a far cry from a stock or stockish sized tire. It still cracks me up every time I see a tfl video and they are airing down for a trail... to 25psi.

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