Tire Surprise

Glad you caught that, imagine changing a tire on the road and discovering the spare is useless!

Wow, that is crazy !! What do the 4 on the ground look like?

I'm curious as to what the date code on the tire says.

That sure is some serious tire deterioration! I have never seen anything that bad. And never used too.

First thing to check is the date on the tires. Just because you know when you bought them doesn't mean that they weren't sitting around in the sun for 5 years before you got them. Go to "Tirerack.com" for instructions on where to look on the tire. But I suspect that whatever you find out, its going to be your fault whether it is or not.

Wow Arizona heat must put a lot of stress on stored tires.

The spare was on the back of the trailer, facing south. The two on the west side are similar (probably 6 hours of sun). On the east side, I didn't see much deteriation(probably 3 hours of sun). All were covered with white covers. Date code is 0410.

Definitely crazy. Please let us know the build date on the tires.

That looks like some serious burning of the rubber. From what I see in the pictures it seems to be confined to the top of the tire which would be most exposed to heating from the sun, even under a tire cover.

I see the high in Surprise, AZ in July could have reached 122 degrees F air temperature. Up here in the Northeast the highest temp I have measured on my tires was 110 F after 2 hours on the road on a HOT (for us) sunny day.

(P.S. - that second picture is so wide I have to do some serious side scrolling to read the posts. )

I had the same problem on a TT I had, only mine popped.

ST tires are supposedly forumlated rubber with more ozone protection and belts better able to resist shifting or separation from squirm typically seen in back in and sharp corners.
I would think they would last a lot longer than five years.
Our G670s, which has faults,on Mh are supposed to last ten years. Ours on the rear are eleven yeas old. I'm going to replace them but they are still supple, soft and no checking or any indications of age. keep dirt off the insides too as dirt sucks oil out of rubber.
Michelins are rated for five years on our MH steer axle. I'm going to try to get a little longer but will monitor condition.
The Michelins on my F150 are six or seven years old and no checking. It is driven often with 197,000 miles on it.
We had Goodyear Wranglers, on our fifth wheel, from the factory. They didn't last a year and had some damage from one throwing the tread.
I think I can recomend Michelin light truck tires, with suitable higher weight rating than the ones on yours from the factory. May have to change rims in some instances because many rims can't take the higher inflation pressures for long.
If you do get aluminum high pressure rims rated for the tire and rv weight.
We've had many sets of Michelins on fifth wheel and three duallies, this F150, cars and others. Just make sure it has the proper load range. I would go one higher than what cam on it. Expect to use more tires if it is a long fifth wheel and gets a lot of jack knifing backing in or jsut normal use. Two axles or three trying to scoot around will make belts shift and delaminate.
jackknifing in back in does better on tires on wet pavement and dirt or grass.