I have been "fighting" a front tire cupping problem on my L99 F350 Dually 2wd since I have owned it.

I got LOTS of paperwork with it, one of which was a service ticket from the dealer where it was bought new (with VERY low miles on it) saying several passing motorists had informed them that the front tires were bouncing down the road.

I have read this service complaint several times and I now feel that has something to do with it.

I bought the truck with 70k on it some 8 years ago-the PO had installed EXPENSIVE Michelin XPS Rib steering tires on it and they were already destroyed by cupping.

I replaced all 4 shocks, and all 6 tires, begged the folks to FIND something wrong/loose/worn out on the front suspension/steering and they found nothing, they aligned it.

THAT set of Cooper Discoverer HT tires did exactly the same thing, except I spent a lot of $$ having the tires rotated.

Now I have a set of Firestone TransForce tires on it and its been to a HD truck shop where I begged them to rip into the front end and FIND something wrong-THEY DIDN'T

THEY installed camber bolts and aligned it, yep, you guessed it STILL CUPPING!!

So, now I'm thinking is it possible that the wrong coil springs were installed at the factory causing this bouncing that the original owner reported to the dealer?

I have now destroyed 2 more tires and getting tired of it.

Suggestions Guys ?? Sorry for the long rant!

 

Does the front end bounce when pressing down on it and releasing? It shouldn't bounce more than once. Cupping is usually a tire "out of round", balance, or shock rebound problem. Coil springs with improper spring rate could also cause bounce. "Stiffer" springs may reduce ride quality, but allow better contact with the road. This is also what the shocks do. They keep you from "dribbling like a basketball" down the road and tire in constant "mesh" with the road. Could you share some pics of the tires and front end?

 

Does it bounce when driving or braking? Or both? What speed does it occur most at?

 

My truck rides and drives very smooth, if its bouncing, no one has told me.

I'm guessing that it WAS bouncing on the PO (OO) at highway speeds..........

I have cross rotated my front tires so many times its not funny in efforts to keep the darn cupping at bay......

I'll get a couple of pictures tomorrow......Thanks Guys!

 

You rotate from front to back. If alls good I would think the Michelin tires should of cured it. It did on my 4x4 drw. If it rides smooth maybe you do have weak springs. You are a 4x4 correct?

 

All I can add,check for bent rims.

 

2wd, rims have been checked at time of spin balance numerous times and found to be straight, I have rotated every which way, destroying all tires that ended up on the front, the cross rotation on the front works for a while, then the cupping destroys them.
I feel nothing in the steering wheel while driving or braking, very smooth ride in a F350 IMO.......

 

How do I find out what front springs (code) came on my truck from the factory?
I'm going to investigate that......I understand that "L" code was the stiffest rate that was offered.........

I think the truck has experienced this cupping since day 1.........

The original tires were Generals, which again when I bought it @70k miles with an already destroyed EXPENSIVE set of Michelin XPS Rib steer tires.....

Then MY set of Cooper Discoverers, and now the Firestone TransForce..........

So, cost of tire doesn't make any difference because they have all done the exact same thing despite countless front end checks and allignments, new shocks, addition of camber bolts, etc..........

 

I had the same problem with my dually until I started rotating every 6000 miles. Putting them on the back for 12000 flattens them back off until their turn up front again. You only have to rotate 4 at a time.

Rotating will not fix damaged tires, only prevent damage from occurring given the front-end is in good shape and it is properly aligned.

 

What I've learned after shredding many front tires:

1. Very few people outside the medium truck world know how to properly align these rigs. They know how to read factory limits, but don't understand our real-world application. Regional driving environments influence the specs, like degree of crown in the roads you typically drive. The weight of that 7.3L behemoth changes the rules on a "passenger" pickup. I sought out and found an "old salt" of a front-end guy, and he tweaked the nose to stop (or slow) the tire damage and nail the minor vibration that I felt in the wheel. I have a thread on this somewhere from this winter.

2. The real estate world has the motto "Location, location, location". The tire world has the motto "Inflation, inflation, inflation". I read up on tires and manufacturer specs, and I learned that the door is all but useless for proper tire inflation. The main reason is the specs were for the factory tires, which we no longer own. I looked up the inflation specs on my tires, factoring about 4500 pounds on the nose of my 4X4, and I repeatedly see about 65 PSI as being the sweet spot. My door says 55 PSI, and a worker at an oil change place (I was on the road) deflated my tires to that level. I spotted minor heel-toe damage to my tires within 400 miles of him doing this, and I learned what happened only because I inspected the tires shortly before and after the oil change. I had driven thousands of miles without issue at 65 PSI, then this happened and my head began to spin and vomit. If you can't find the inflation/weight specs on your tires, use chalk across the tire and go for a short drive. Edges missing chalk? Inflate 10 PSI and try again. Center missing chalk? Deflate 10 PSI and yadda, yadda, yadda.

3. Is it cupping, heel-toe damage, or something else? You need to be very specific to properly diagnose the root cause.

4. It's not a sports car - go the posted recommended speed around highway corners. 8000 pounds of centrifugal force pressing on your tire edges plays hell on the rubber.

6. (not a typo) Rotating the tires every 5000 is a common recommendation. What this does is take the bit of wear and place it in the rear - to "lathe" it flat again. I feel this is a Band-Aid. It's still a good idea to rotate tires on a regular basis, but this should be to prevent uneven tire wear, not fix it.