Tire Cupping - Page 2

papap · 10-06-2011, 08:39 PM

May money is on it being over inflated.

fast murray · 10-06-2011, 08:45 PM

No weights on the tires at all. I hope that's the problem. I'd feel better about getting it where I need to be and back home. We have a few trailers at work and I have a cargo trailer at home and none of them have balanced tires. I don't know why but I suppose that if a tires was really goofy, it could do cause cupping. Its just weird that it never showed up until now, unless I just missed it. I also feel the tires when we stop for fuel and they fon't feel hot. Slightly warm but no different than the truck. Could removing and reinstalling the brake assembly cause an alignment issue? I tought about how it was jacked up but even if the axle was jacked from the middle I'd think it would have tipped the tire out and wrecked the outside tread. Now for the shameless plug: We are a competition BBQ team from SD and we pulled it to KC for the American Royal Invitational BBQ and left it there for a couple of weeks until we pass through on our was to Lynchburg, TN to compete in the Jack Daniels World Championship Invitational BBQ!!! Before all of this, we'd have been lucky to drive 100 miles from home.

papap · 10-06-2011, 08:55 PM

Good luck with tire and BBQ.

Dave_Monica · 10-06-2011, 09:03 PM

Quote:

Originally Posted by fast murray

Now for the shameless plug: We are a competition BBQ team from SD and we pulled it to KC for the American Royal Invitational BBQ and left it there for a couple of weeks until we pass through on our was to Lynchburg, TN to compete in the Jack Daniels World Championship Invitational BBQ!!! Before all of this, we'd have been lucky to drive 100 miles from home.

Shameless indeed!

How about I PM my mailing address so I can verify the quality of your BBQ.

Dave

jimh · 10-06-2011, 09:04 PM

i'd say swap the position of that and one more tire ie spare and see if it is tire or position.

papap · 10-06-2011, 09:11 PM

He said he swapped the cupped tire with the spare. But has not pulled it yet. So he needs to just keep a eye on it.

fast murray · 10-06-2011, 09:16 PM

I have about 20 miles on the brand new spare now which has the same load rating as the rest. I'll pull it 200 miles before camping overnight and then 450 the next day to Lynchburg.

jimh · 10-06-2011, 09:54 PM

Quote:

Originally Posted by papap

He said he swapped the cupped tire with the spare. But has not pulled it yet. So he needs to just keep a eye on it.

sorry abt that, i missed it.

**Herk7769** · 10-06-2011, 10:12 PM

An overly hard tire will bounce, Remember that we have no "shocks" per se to smooth out the road shocks. Once they start bouncing they will start to wear funny (well not so funny). Cupping is a sign of bad shocks in an automobile.

I still question how a C rated tire would up on that camper with 4 other Ds (3 on axles and 1 on the spare carrier).

fast murray · 10-06-2011, 10:18 PM

Quote:

Originally Posted by herk7769

I still question how a C rated tire would up on that camper with 4 other Ds (3 on axles and 1 on the spare carrier).

I'm reasonably sure that it has a D stamp on it. It is rated at 2150#, the others had a D stamp but were rated something like 2450#. The only thing I can come up with is the tire supplier mistakingly had them together and delivered them to the tire dealer that way and along the way nobldy noticed. Appearancewise, they all look the same. Even after I discovered the cupping and the rated max pressure, I sat there staring at the 2 side by side and couldn't see any difference. I can't wait to get them home so I can look again. Maybe even post a pic.

**Herk7769** · 10-06-2011, 10:22 PM

Quote:

Originally Posted by fast murray

I'm reasonably sure that it has a D stamp on it. It is rated at 2150#, the others had a D stamp but were rated something like 2450#. The only thing I can come up with is the tire supplier mistakingly had them together and delivered them to the tire dealer that way and along the way nobldy noticed. Appearancewise, they all look the same. Even after I discovered the cupping and the rated max pressure, I sat there staring at the 2 side by side and couldn't see any difference. I can't wait to get them home so I can look again. Maybe even post a pic.

If it is rated D it should be max press 65.
C Rated tires are max press 50.
Pics sure would help clear this up.

fast murray · 10-06-2011, 10:24 PM

For what its worth, I was under the slideout at a BBQ contest doing all this detective work.

**wmtire** · 10-08-2011, 10:04 AM

Quote:

Originally Posted by fast murray

I'm reasonably sure that it has a D stamp on it. It is rated at 2150#, the others had a D stamp but were rated something like 2450#. The only thing I can come up with is the tire supplier mistakingly had them together and delivered them to the tire dealer that way and along the way nobldy noticed. Appearancewise, they all look the same. Even after I discovered the cupping and the rated max pressure, I sat there staring at the 2 side by side and couldn't see any difference. I can't wait to get them home so I can look again. Maybe even post a pic.

As far as tread goes, the tires will look identical...it's in the composition where there is a difference.

From everything you have posted so far, I have a feeling you have bias (or non-radial) tires installed.

When you say all the tires have a D on them, is this D listed in the size of the tire? Example ST225/75D15.

If that is the case, that D is not a Load Range (although many people do confuse it).

The letters you see in the size, state the construction of the tire as follows

R = Radial construction
D = Diagonal construction
B = Bias construction

D and B (Diagonal and Bias) mean the same thing, as some manufacturers will use a B and some will use a D. I attached some pics that show the difference in the construction of a Bias/Diagonal and a Radial tire.

You will need to look along the sidewall some more (not in the size) and you should see something like "Load Range" or "LR" or "Ply Rating". There will be a letter code after these words that tell you the ply rating of the tire. It may also just flat out state the ply rating with a number (6,8,10).

C = 6 ply and 50 psi pressure
D = 8 ply and 65 psi pressure
E = 10 ply and 80 psi pressure

Now there also exists the possibility that a tire got molded wrong in the manufacturing process. It could be a 6 ply tire, that got an 8 ply Load Range molded on the sidewall (or vice-versa)

I just have a feeling that you have bias/diagonal tires, as they are more prone to the problem you say you are having also. I do believe you have some kind of axle problem too, since you stated the tire is only wearing from the middle of the tread towards the inside of the tire. It is also easy to damage/bend something when you jack it up....and I am tending to believe this happened when they repaired your brakes.

Check out this link, and see if the pictures shown reflect your condition.

HOW TO READ TIRE WEAR

and you can scroll down the page from this link to read about cupping/feathering problems on rv's.

RV Tires: That's Where Rubber Meets The Road!

fast murray · 10-09-2011, 06:08 PM

What could have happened to the axle by just fixing the brakes? Could leaving it sit for a couple of days on 3 tires cause this? I'm going to need something to go on when I show up with a gripe at the shop where this all started.

**wmtire** · 10-09-2011, 07:06 PM

Quote:

Originally Posted by fast murray

What could have happened to the axle by just fixing the brakes? Could leaving it sit for a couple of days on 3 tires cause this? I'm going to need something to go on when I show up with a gripe at the shop where this all started.

You can actually bend the axle, depending on how/where you jack the trailer up at. I took the following from the Dexter website:

MISCELLANEOUS - Is it okay to jack up my trailer?
Dexter recommends that you do not jack up the trailer on the suspension components because there is always the potential for damage. Bent hangers, leaf springs, or axle tubes can cause bad axle alignment with bad tire wear resulting. Also, many trailer builders do not use Dexter hangers and we have no idea how strong these hangers may or may not be. Therefore, we take the conservative approach and recommend jacking up only on the trailer frame.

Lippert Axles warn on page 5 not to lift by the axle or suspension components:

http://www.lci1.com/images/Flyers/Ow...r-axle-web.pdf

Here's a little how-to to check the alignment:

Trailer Tire Problems & Tips

jimh · 10-10-2011, 06:53 AM

i have had a tire store balance the trailer tires (on newly purchased tires) but for the most part, there are no weights on my tires.
i do have a cargo trailer that is demonstrating cupping in one tire. that tire also is loosing air over abt a week's time. i probably have between 5 and 10 thousand miles on that trailer.
for a tire to demonstrate cupping after abt 300 or so miles unusual.
in my case, i believe it is caused by low air pressure and weight distribution. on urs, it just sounds like a bad tire.
when the cord breaks, they tend to squirm. sometimes, u can jack the tire and spin it and see the tread not staying in line.

fast murray · 10-10-2011, 07:21 PM

Perhaps too high of air pressure and overloading could cause a broken belt? I had 2 big meat coolers on the dinette which was obviously slid in but they favored that side. We've had a guy tell us that this is more than likely a bent axle caused by turning too sharp on pavement. Surely I'm not the only one that has to make tight turns now and then.

flyrotor · 10-11-2011, 12:24 AM

Have never heard of bending the axle from turning too tight, It could be possible to damage the tread with a scuffing action in a tight turn, but only if grossly overloaded.

Now maybe if they struck a curb or large object it could happen. More likely improper handling such as jacking in the wrong location would cause the axle to be bent.

The fact that the axle recently had brake work means that it has been jacked up on that axle.

Also, one of the most common cause of cupping is an out of balance tire, hence the tire bouncing as it rotates at higher speeds. It may be difficult to pin point the out of balance as the tire has lost tread and therefore weight were the cupping took place.

Personally I don't believe it has anything to do with one mismatched tire, rather it is more coincidental... IMHO....

Best to do as you did and place the spare tire (matching for the other 3) watch it closely, feel it often for temp differences, and replace the now lighter weight spare with one equal to the rest the tires.

If you see cupping or feel temp differences, then it probably is the axle.

Also, a good tire shop with a good alignment machine should be able to test the axle to see if it is damaged or incorrectly aligned.

fast murray · 10-11-2011, 06:29 PM

Thanks everyone for all your tips and suggestions. We are fairly new to 5th wheeling and this is by far the longest trip we've been on or likely will go on. With all that will go on at the event itself I'd like to make the trip itself as uneventful as possible. Thanks for keeping up with my now 4 page thread!

fast murray · 11-28-2011, 09:03 PM

Update, we pulled the 5th wheel from Kansas City to Tennessee and then back to South Dakota. The replacement tire doesn't show any signs of wear to the eye. I'll try to get some pics of the weird sidewall info. I hit a nail with one of the other tires on the way home and had to get 1 new one. Did you know that Walmart will not touch your RV and that you must roll the tires in for them?

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