Tire/Axle Question

Gdetrailer wrote:


Annd HERE is what Dexter says..

Page 77..


Click For Full-Size Image.

Snip...

Cupping can come from an out of balance issue or wheel bearing adjustment issue according to Dexter axles manual.


My tire shop tells me once they start wearing odd, nothing can slow it down or fix it other than replacing..

The chart shown above is a text book standard chart for tire wear. I do not disagree with any of it. However in this case, we are talking about a travel trailer made in the RV industry, not a car, truck etc. where that chart actually fits better. A tandem axle trailer made in the RV industry with no steering on the lowest budget that just gets by, is very different then an automobile with very good and stable suspension.

I do agree 110% with the statement about once a tire starts wearing bad, it will continue to wear that bad even after the problem is corrected. My step dad was in the garage business for over 40 years working on autos, and I can still hear him telling me that fact, that the tire wear will continue even if the issue was corrected.

Before we start telling Campermama that their wheel bearings are shot or set wrong causing the tire wear they are seeing, it might be better to first confirm that actual cupping as shown in that chart is root cause of the wear on the tires. There was going to be pictures posted so we can see what they are seeing. That can then help a lot better then speculating that cupping is actually happening. Maybe Campermama misdiagnosed the wear and called it cupping, now folks are telling them to fix cupping, fix the tire balance and wheel bearings.

I have measured axle alignment on several campers, corrected bent axle tubes, repaired incorrect hanger locations, and worn suspension to name a few of the issues creating tire wear on a travel trailer. While I have not done thousands of campers on alignment checks, out of all of the ones I did do, none of those tire wear issues were due to actual cupping of a tire due to a wheel bearing going bad or the tire being out of balance. I'm not saying those conditions cannot exist, but I would say it is highly unlikely given what we know so far.

The statement of, an out of balance tire issue causing tire cupping wear on a TT, let's think about that for a moment. Think about how many thousands of travel trailers and 5th wheels leave the factory every day with unbalanced brake drums and tires. Do they all have tire cupping?

If the wheel bearings where set wrong, having excess play, and there is 10K miles on the camper, odds are high, those bearings for 10K miles would be severally damaged to the point of total failure or close to it. Has anyone ever seen a documented trailer wheel bearing survive a bad setup that long?

And then what are the odds that bad bearings and out of balance wheels so bad to cause cupping, just happened to end up on the same axle tube, yet the axle tube next to it, does not have the issue?

With what little we know about this camper wheel alignment, actual tire cupping does not stand out as the root cause of the tire wear. If we can get some pics of all 4 tires, that may help a lot better then assuming cupping is the root cause.

Hope this helps

John