whiring road noise, cupped tires/shocks?

[4x4JeePmaNthINg]

I spent the last few days trying to find out what a noise was on my jeep. I pulled front shafts, swapped unit bearings, even replaced one that I had laying around, removed drive shafts. This sound remains and comes about at 30-50 mph.

The Jeep has 35" Mtrs and they have some cupping on one of the small treads. They all have this and I rotated them the last oil change, the sound didnt change. It sounds to be from the front of the vehicle.

Assuming what I am hearing is now due to this cupped tire issue. What would cause this now? Ive run many tires on this jeep, but Ive never had tire noise like this before, so I have no real experience on how to go about this noise issue.

My shocks are bilstein 5100, and when trying to rock the car and look for excessive bouncing, I see none.

Can these shocks still be bad even though the jeep isnt flopping around?
Should I test these shock in any other way?

Are bisltein 5100s up the task of running 35"s or is this a bit big of a tire for a shock designed for the XJ?

I appreciate any insight,

Thank you in advance.

 

[RCP Phx]

Once the tires start cupping then it just gets worse. I'd start with a tire re-balance (tires may need to be "trued"), a alignment from a good machine, and consider a beefier shock. What rims are you running and have they been for true-ness and balance?

 

[RCP Phx]

BTW, what air pressure do you set them at, and try to get a pic of them.

 

[Anak]

Another place to look--The plastic shroud for the mechanical fan.

I had a comparable noise that I spent months trying to track down. I finally found that the plastic shroud was bending back just enough to barely touch one of the fan blades, and only when the Jeep was up to speed.

 

[4x4JeePmaNthINg]

The rims are a basic steel wheel, 8"wide to hold the bead. Ill try and get a photo if I still have an image hosting website account.

The tires have been run from 23-30 psi, ive never found a sweet spot.


The machine alignment may be worthwhile, its a 3 link and Ive done all the alignment with some leveled angle iron bolted to the hubs and then set the toe in to 1/8. Ill look into rebalancing them to.


I will give the fan a look to, at this point its not the drivetrain and I'm out of ideas if its not the tires.

 

[4x4JeePmaNthINg]

between 40-60 mph the noise can be heard about 27 seconds in. Its a rotational warbling sound ide say. https://www.youtube.com/watch?v=hOX3jBvMBOg

 

[4x4JeePmaNthINg]

 

[4x4JeePmaNthINg]

not sure how to get the drop box link to post. Ill try tire pics again later.

 

[4x4JeePmaNthINg]

https://www.dropbox.com/s/y828cv0768rtczw/20211104_204137.jpg?dl=0

 

[4x4JeePmaNthINg]

https://www.dropbox.com/s/yfwq0vj2jqsd5i6/20211104_204020.jpg?dl=0
https://www.dropbox.com/s/nm0iv1957j0cbjx/20211104_204308.jpg?dl=0
https://www.dropbox.com/s/omfqoh81nmsrv35/20211104_204419.jpg?dl=0

 

[RCP Phx]

The photos look like to much camber/toe, and your video shows "private" so I can't see it!

 

[4x4JeePmaNthINg]

hopefully the video is fixed

 

[RCP Phx]

That's a strange one! Do you feel it in the seat or steering wheel? How old are the tires?

 

[4x4JeePmaNthINg]

The tire are about a year old with loooots of miles on them now. There is vibration in the wheel and I can see the passenger seat vibrate a bit, though I figure thats a balancing issue and perhaps the fact that its running tractor like tires hahah.

 

[4x4JeePmaNthINg]

Another place to look--The plastic shroud for the mechanical fan.

I had a comparable noise that I spent months trying to track down. I finally found that the plastic shroud was bending back just enough to barely touch one of the fan blades, and only when the Jeep was up to speed.

Ill look at this as well, did the fan shave away a groove in the shroud?

 

[Anak]

No. When I say it barely touched I mean it really barely touched. It just created a bit of a clean spot on the inside of the shroud. Probably a section about 2" long and 1/2" wide at its widest.

 

[SleeperXJ]

Kind of sounds like gear noise. Might be worth looking at the oil in you differentials.

 

[4x4JeePmaNthINg]

Kind of sounds like gear noise. Might be worth looking at the oil in you differentials.

So far I have drained fluid and checked the backlash on the front diff, I have not on the rear diff yet, though the sound isnt coming from the rear of the jeep.

If pulled front axle shafts and drive shafts, can it still be a rear diff? Neither pinion is loose.

 

[4x4JeePmaNthINg]

Ive never set up a rear differential C8.25 and I have an ARB in mine so I havent been keen on pulling it without knowing how to properly set up the backlash again, nor do I have the tool to tighten those dohickies for backlash.