Would you run these tires?

110 to 115degr F is what you would expect driving that speed.
but that RF is getting hotter ( when not in the sun that side) indicates , or higher loads on those tire , or camber angle as I described . then one sidewall gets hotter but the other colder wich makes the insided tire temp to stay reasonable but the hotter side can have such high temp that to much sulfur brigdges form in the rubber wich makes the rubber to hard. This is the kind of damage I was inplying in my former posts.

But now the old tires are off , do you still have them and where the damage only on one side?

so still possible the damage is done by to high temp.

doctorroy wrote:
Are you nuts or is this an April 1st joke?

Am I nuts? I don't think so, why do you ask?

Here is another data point: Tire temps while towing today (in *F):

LF 107
LR 107
RF 120
RR 113

RF tire was the one shown to be egg-shaped and deformed in the pic. Possible that higher tire temps while towing indicate overloading?

This was my first trip with these brand new tires. Are these temp differences meaningful?

Ambient temp 71* and towing 70 mph.

My Travel trailer tirepressure calculator gives only 63 psi with all the reserves and then going from only 10% of totalweight on pin=850 lbs. Your given 1200 lbs is 14.1% and this then would only need 60 psi.
another spreadsheet filled in with that 1200 as pinload gives even lower pressure of between 56 to 62 psi needed for speed below 87m/h.
so my conclusion of using to low pressure must be wrong.

Other possible reason can be alignment like camber. probably the other sidewall does not have those crackes in the lower part of profile blocks.
Your picture shows most damage on left side of treath.
Camber can be roughly measured with a water level, yust to see if its extraordinary . then one sidewal deflects more and produces more heat. Hold the water level straigt up against the rimm, and make the airbubble between the lines, and see if there is large diffence in space at botom and top of rimm. Dont hold it against the tires because they have a bulbe in the sidewall at the bottom , wich would give valse negative camber angle. Seen from behind negative camber would give this seen from behind or front /-\.
Positive camber this \-/.
Damage by heat only happens when driving at speed, standing still the tire can stand much more bending of the sidewalls.

But when you are using a weight distribution hich, the load on tires is when connected to car shifted to trailer wheels and front wheels of towing car. Then it is possible that instead of 7300 lbs you even have 8000 lbs on trailer tires .
But then even filled in my pressure calculator gives 70 psi as highest pressure , so you would also be OK with your 70 psi filling.

Are you nuts or is this an April 1st joke?

Trailer is 34' dual axle, so 4 tires. Trailer came from the factory fitted with ST225/75-15 tires, load range "D". I upgraded to these LT tires 3 years ago for increased load capacity and wider safety margin.

Last time the trailer was weighed, it was 8500 lbs total, 1200 lbs on the tongue and 7300 on the axles. 7300/4=1825 lbs load on each tire, assuming all tires are loaded equally.

The two tires on the right side of the trailer were in considerably worse shape than the 2 on the left side. Two possible reasons, 1) with the slideout extended, the 2 left tires are in the shade while the right ones sit in the sun, and 2) the left tires sit on bricks and the right ones sit in the mud where I have the trailer parked.

The right side is also where the kitchen is, so full refrigerator and pantry, along with storage for bottled water and beer. The fresh water tank is centered in the frame and ahead of the axles.

Even if the trailer was considerable heavier than the last scale slip, and even if it was loaded unequally left-to-right, there should still be adequate capacity so that these tires are not overloaded.

I typically drive 65-70 mph with the trailer so also below the speed rating of the tires as well.

Any observations or advise to increase the longevity of the new tires would be appreciated.

Then give the weight on the tires and I will calculate a save pressure for that tire, and that is how high you can go without bumping so screws loose from woodwork, or disches and glasses get broken. Then maximum reserve for things like , pressure loss in time, unequall load R/L ( only one side damaged??) incidental extra load, misreadings of pressure-scale , and misyudging of load on tire.

Already found maximum load of 2680 lbs at 80 psi

Also give configuration , so howmany axles and total of tires on the road when driving ( so not the spare).

This damage must be from to much deflection, so I expect you being surprised about the real ( over) load on your tires.

carl2591 wrote:
what is the pressure of that tire?..

That's an E-rated LT tire at 70 psi. I typically run them at 75 psi.

what is the pressure of that tire?.. just at first glance it appear to be over inflated?.. but i have seen that same condition on other ST tires but not so much on LT tires..

guess that is why a lot of airstream guys are going with the Michelin LT tires vs the ST tires.

BurbMan wrote:
A few additional pics of these tires. One thing I learned is that tires should be FLAT across teh tread, when they start to egg out like this something is coming apart:

Nope...I'd get new tires before the trip.

The damage most likely began under the thick profile blocks, by to much heat of the rubber on the innerside under those blocks. courced by to much deflection for the speed you drive,wich on its turn courced by to low pressure for the load on tire.
The cracks in the thinner spots, so the grooves in the profile and the side of the tire only in the profile-blocks, are probably because the rubber under the block was pulvered so had no construction there.
This gives more force on the thinner rubber .

Your last picture also indicates that the treath beneath the profile blocks on left side already came loose.

So If you have your new tires, review the needed pressure for that.
I can help you with it if you give weighed load per tire , second best weighed axle loads , but in lack of that GVWR or GAWR.

Special trailer tires can do with a bit lower pressure so more deflection ( 1 or 2 psi ) because the treath is thinner so isolation of those important rings of the tire , that produce the most heat, is a bit less then a LT tire .

So the thinner rubber parts of tire, where you see the damage , most likely have a intact rubber sturcture.
The real cource of damage you will only see if cut a slice of the tire , as soon as you replaced them ( not before:S)