Help Me Trouble Shoot: Cupped Tires and Front End Rattle

[GxDxWxB]

Im very interested to hear what they diagnose for the rattle. My 2018 is doing the same. I have noticed a bit of seepage on my front driverside shock. When I get home later this week I'll be taking it into ford as its still under warranty.

 

[acremer24]

As far as the tires go, my suggestion is to replace the factory BFG's. I had the same problem with the BFG's on my 2012 Raptor, even though I rotated them every 5k miles. I put on Nitto Trail Grapplers, and problem solved.

 

[PorterW1111]

check the front brakes. i know it sounds crazy but i chased a similar issue on my wifes rover. had a loose retainer clip which caused the pad to move around. a "warped" rotor can also cause vibration/tire movement as well. just think of how little amount of weight that is used to balance a tire. now think about your solid metal rotors and large break pads pressing against them. if they arnt perfect things will wear. this might not be the case but its worth checking...

 

[smurfslayer]

So, first things first. What do you mean by ‘cupping’ because it does not sound like this:
https://www.bridgestonetire.com/tread-and-trend/tire-talk/tire-cupping

it sounds like you are reporting a fairly symmetrical wear on the inside of your tires, not an uneven wear. Evenly overworn on the inside of the tire is misalignment.

Now, if you’re having a rattle during or incident to suspension travel, something could be loose, broken or disconnected, but what are the chances it would be affecting both sides given your stated symptoms?

I will say this much, for those of us who ran for a fairly significant amount of time at the recommended or close to recommended psi, put a depth gauge on the inside and outside of the tread. Lucille’s shoes are pretty significantly worn more on the inside, uniformly.

 

[Rustler]

@smufslayer, This is decidedly NOT even treadwear that is excessive on the inside. Every other tread block (on the inside) is more worn than the one before or after, and more worn at the front than the back of the tread block. That's why I tend to think that the failure to cross rotate (and therefore get that inside edge of the front tire to the outside after rotation) didn't cause the cupping, but rather exacerbated it. The tech and head of service at the dealership both agree that it looks like "cupping" not excessive wear on the inside.

Interesting thing about the rattle is that it is not incident to suspension travel. When I compress the suspension on a road dip or undulation it compresses quietly and smoothly (as far as I can tell from the drivers seat). It is hitting a pothole, road seam, join in the pavement, or other very small but sharp road imperfection that I hear it. It's at it's worst on a wash boarded dirt road, or a rocky jeep trail.

You raise an interesting question about whether the noise is on both shocks, or just one. As I mentioned above, the tech is telling me that using chassis ears he thinks he has isolated the noise to the shock assembly, but he didn't specify right, left or both, and at the time I didn't think to ask. I will ask when I follow up with them, hopefully today or tomorrow.

Got some pics last night. Here they are.

I appreciate the input so far, Thanks.

 

[smurfslayer]

This is decidedly NOT even treadwear that is excessive on the inside. Every other tread block (on the inside) is more worn than the one before or after, and more worn at the front than the back of the tread block.

I understand what you’re describing as feathering. https://www.bridgestonetire.com/tread-and-trend/drivers-ed/tire-tread-wear-causes

although the unevenness you describe may mean more. The front and rear tread block difference is normal particularly if tires are only rotated front to back, not side to side.

I am still leaning towards alignment.

(and therefore get that inside edge of the front tire to the outside after rotation)

How would tire rotation move the inside edge of the tire to the outside?

It is hitting a pothole, road seam, join in the pavement, or other very small but sharp road imperfection that I hear it. It's at it's worst on a wash boarded dirt road, or a rocky jeep trail.

maybe if you could mount a go-pro or similar pointing at the suspension it might help narrow it down.

 

[BRUCE1]

cupping 99% is air pressure.

 

[RaptorFun]

Too low or too high causes cupping?

 

[Rustler]

@smufslayer

I think we're talking cupping, not feathering. The uneven pattern is every other tread block wearing on the inside band as you move around the circumference of the tire, not uneven wear across the tire from inside to out. See graphic below. what I am seeing is more like what it describes as "scalloped wear." Also, there is another pic from a Tacoma forum below. It's a duratrac off a taco, but this is exactly what my tires look like. Here's the forum post: https://www.toyota-4runner.org/5th-...s-cup.html?s=f473d652fc8943526741360de617e515

I think your right that the "heel and toe" wear (more wear front to back of each treadblock) is a common occurrence, and that would be exacerbated by the failure to cross rotate, which would change direction.

I was incorrect about the cross rotating moving the inside to the outside. As you point out it would change the direction of travel, but not move the inside of one to the outside of the other.

I see a lot of references to both worn shocks and alignment causing this issue.

Keep in mind that the truck was aligned by the dealer, and reportedly aligned on spec with no adjustment. I am interested to see the paperwork, but the truck was dropped off at my house while I was at work, so I haven't had a chance to see it yet.

It is entirely possible the noise and the tire wear are not related. It could be that the tire wear is a function of not cross rotating, and not doing it frequently enough. I will rotate at 5k moving forward in any event.

Thanks again for the time and input! Happy to hear more ideas!

 

[Rustler]

Here's another pic (not my tire) that looks very much like what I'm seeing: