One tire wearing faster than the other on a set of duals

That’s a good eye, to catch that!!

 

Axle flex would cause the inside one to wear more I'm pretty sure

 

Have you had an alignment?

 

It does seem excessive. Could it be too much wheel end play, loose bearings. I wonder.

 

Again I'm pretty sure loose wheel bearings would cause the inside to wear more

 

I had an alignment 3 months ago and I’ve checked bearings are tight.

 

Kinda far out there, but here's a thought.

Right rear being drive wheels it should run a little warmer on that corner, and you have 2 wheels of different metals with different rates of heat transfer, dissipation and expansion.

If there's enough heat being transferred to the wheels from the road through the tires, differential and brakes to expand the aluminum wheel 1/1000 of an inch greater than the steel wheel, it might cause the one tire to wear faster than the other because it's grown slightly and bearing slightly more load which could make that tire run hotter, expand more and wear faster.

Sounds out there, but you could find out pretty easily if you had a full load on, got the tires hot, and checked them with one of those hand held electronic thermometers or heat sensor guns, whatever they call them things.

Just a thought.

 

Aluminum’s will warp also. Steels run true. I was amazed to find out, years ago. A tire guy showed me, my steers had a bit of wobble. I was always told steel will bend, aluminum will crack. But apparently aluminum will flex and get out of whack.

 

I see alot of daycabs that pull long tubes local delivery. I have seen similar wear in that application. The only other thing I can figure is alot of weight with more turns to the left than right causing extra wear on the outside tire. In this application the outer is almost always thinner.

 

You triggered another thought.
Stresses are created in various metals during production and manufacturing processes that over a period of time from numerous hot and cold cycles will cause those stresses to relieve and the metal will shift or change shape.

If you've heard of stress relieved engine blocks, or seasoned engine blocks, you'll know what I'm talking about.
Race engine builders prefer a block that has over 100,000 of city driving over a block with 100,000 miles of highway driving because the block had relieved most of the stress that was cast into it due to frequent hot and cold cycles that the highway engine hasn't encountered, there's still stress in that engine and they will remain until that block has undergone many more hot/cold cycles.
When the engine is stress relieved there's less chance of core shift occurring and the cylinders can be bored straight and round and stay that way, the engine will make more power with straight round cylinder holes and alignments within the block won't change over time.

Don't see why it couldn't happen to an aluminum wheel if it had enough hot and cold cycles.
It happened to one of my commercial grade aluminum frying pans, wobbles all over the stove element until it gets got.