Highway pressure for 37's on a 392XR?

[richk225]

Read the thread title again.

Okay I admit it I totally missed it, in my defense I am involved with what is happening in Poland and the Ukraine, a lot of family over there and heading out soon. I do appreciate you pointing that out to me

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[Dyolfknip74]

Okay I admit it I totally missed it, in my defense I am involved with what is happening in Poland and the Ukraine, a lot of family over there and heading out soon. I do appreciate you pointing that out to me

You don't owe me an apology or a reason. Just pointing out it was mentioned.

I hope your family stays safe.

 

[1996cc]

28 max. I’m usually in the 25 range.

Hit 90 today on gravel roads at 9psi, does that count at highway speeds,

 

[richk225]

28 max. I’m usually in the 25 range.

Hit 90 today on gravel roads at 9psi, does that count at highway speeds,

That is cool that you can still drive like that at 90 years old LOL
That`s more like fly a way speed!
Are you running true bead locks?

 

[DavidArmen]

The xr wheels absolutely do not have a 4.5” backspace. That would cause the wheel and tire to stick out of the fenders by like two inches.

this is what an 8.5” wheel with 4.5” backspace looks like:

also, the stock xr wheels are only 8” wide.

 

[richk225]

The xr wheels absolutely do not have a 4.5” backspace. That would cause the wheel and tire to stick out of the fenders by like two inches.

this is what an 8.5” wheel with 4.5” backspace looks like:

also, the stock xr wheels are only 8” wide.

I am taking my spare off today to modify the brake light, I want to check the backspacing, and you are right it is a 17x8 wheel

 

[DavidArmen]

I am taking my spare off today to modify the brake light, I want to check the backspacing, and you are right it is a 17x8 wheel

Please update us! It should be about 5.5” backspace or more.

 

[stumblinhorse]

Please update us! It should be about 5.5” backspace or more.

XR rim specs
Backspacing 4.4
Offset +12
Diameter 17
Width 8
Weight 41 lb.

thanks @Trauma PA

 

[Chris-AZ]

I'm surprised Jeep would violate BFG's minimum width spec of 8.5". Seems like it would be a liability.
392 XR comes stock with BFG KO2 35x12.50R17. That is why I assumed the special 392 XR wheels were 8.5" wide and not 8.0". BTW, regarding backspace, the tires do stick out which is why they added the extensions to the fender flares. Even then they do still stick out a bit. I'll reduce highway pressures on my new 37 KM3's to 32 psi. They are at 38 (cold) now.

I hope that special 392 XR wheel offset allows my next mod, suspension to clear. Ordered Metal Cloak 3.5" game changer kit (plus front driveshaft and brake lines) and for shocks I have Fox 3.0 IBP for the 3"-4" lift. Expecting the end result to have more up travel and sit about 2.5" higher than the 392XR sits now. Also a full set of under armor on the way from Metal Cloak. This will complete the build for now (already did bumpers, winch, fuel, lights, rockslide steps, AAL interior system).

BTW, I run 44 psi in my Raptor but it gets driven at high speed both on and off road. I'm sure I could get away with less pressure but the short sidewalls of a 35x17 can lead to pinch flats hitting rocks at high speed such as I encounter in Baja. I'm sure 44 psi is overkill, but you know what they say, overkill is under rated!

 

[stumblinhorse]

I'm surprised Jeep would violate BFG's minimum width spec of 8.5". Seems like it would be a liability.
392 XR comes stock with BFG KO2 35x12.50R17. That is why I assumed the special 392 XR wheels were 8.5" wide and not 8.0". BTW, regarding backspace, the tires do stick out which is why they added the extensions to the fender flares. Even then they do still stick out a bit. I'll reduce highway pressures on my new 37 KM3's to 32 psi. They are at 38 (cold) now.

I hope that special 392 XR wheel offset allows my next mod, suspension to clear. Ordered Metal Cloak 3.5" game changer kit (plus front driveshaft and brake lines) and for shocks I have Fox 3.0 IBP for the 3"-4" lift. Expecting the end result to have more up travel and sit about 2.5" higher than the 392XR sits now. Also a full set of under armor on the way from Metal Cloak. This will complete the build for now (already did bumpers, winch, fuel, lights, rockslide steps, AAL interior system).

BTW, I run 44 psi in my Raptor but it gets driven at high speed both on and off road. I'm sure I could get away with less pressure but the short sidewalls of a 35x17 can lead to pinch flats hitting rocks at high speed such as I encounter in Baja. I'm sure 44 psi is overkill, but you know what they say, overkill is under rated!

BFG adjusted it‘s spec in 2 areas for the 392XR. Width and speed rating. If you look at KO2s now they are the only tire spec’ed for 8” and 112mph.

 

[Chris-AZ]

BFG adjusted it‘s spec in 2 areas for the 392XR. Width and speed rating. If you look at KO2s now they are the only tire spec’ed for 8” and 112mph.

Where did you find this? The place I looked on the BFG website still says 8.5” min width.

 

[Chris-AZ]

BTW I just looked at sidewalls.
392XR 35x12.5R17 KO2 says 113/110S
Raptor 35x12.5R17 KO2 says 113/110T
Different tires…

 

[richk225]

BTW I just looked at sidewalls.
392XR 35x12.5R17 KO2 says 113/110S
Raptor 35x12.5R17 KO2 says 113/110T
Different tires…

The tires for the Raptor have a higher speed rating

https://simpletire.com/learn/tire-b...gWxHgVdkL7mNQG3tIPaKPVVVXX_2cxZEaAnmOEALw_wcB

 

[stumblinhorse]

Where did you find this? The place I looked on the BFG website still says 8.5” min width.

I looked on their site. The ones on the XR are 315/70/17s 113S. S speed rating is new for the raised limit of an XR. But I assume your XR has 35x12.50x17s? Wonder how that happens. Jeep has some splaining to do…

 

[Chris-AZ]

That is not the tire my 2021 392XR came with from the factory. Mine came with 35x12.5R17 113/110S KO2. Perhaps the 2022 models have a different tire now?

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