I know many have upgraded to 17.5 wheels and tires, and for me I had no reason to justify the upgrade until we had two leaking aluminum 16" rims on the way to the rally. Bottom line - check your rims for small spider-web type etchings. They may be the start of stress fractures.

I also broke the two rear spring hanger wet bolts.

Don't know exactly what the sequence was, but here is my guess:
Broken wet bolt on RR, creating more stress on the LR hanger and both wheels
Stress fracture in RR wheel. Reluctantly replaced with spare steel wheel/Westlake original spare.
New wet bolt in RR causing stress on weakened LR bolt and LR aluminum wheel.
Broken wet bolt on LR.
Stress crack on LR aluminum wheel. Replaced with new steel wheel and Sailun that was on the ground.

I upgraded to 4,000 lb springs, Dexter equalizers and Dexter wet bolts/bronze bushings two years ago.

Lippert has examined my suspension and says hangers are good, axles and springs are good; they are replacing the equalizers and bronze bushings in the spring eyes. And solid bolts on the spring ends.

And, simply for informational purposes, here is the Sailun 637 on the 16" rim with 50,000 miles on it. Continue to be very impressed with the Sailun tire.

My 2015 wheels look the same as your , I didn't have any leaks. I would say if they tires got broken down you would find a white caulk on the bead seal area. 95% of the time 5 year old aluminum wheels need to have bead sealer put on the wheels after they are lightly sanded then sealed at the bead. Its like a black rubber paint they brush on to stop the bead from slow leaks. very common problem. as for your wet bolts my RL-38 broke the driver side rear out of the hanger some place between PA and Elkhart( Morryde) so I maybe traveled 450 miles tops like that. The bolt was completely gone when I backed into the service bay at Morryde. Both of my drivr side 3500lb springs where flat and the curb side still had a fair amount of arch so I think your idea of 4000 lbs spring is good idea.

Mark, thanks for your additional information about the aluminum rim bead seal. I was not aware of that.

In my case, both aluminum rims developed a leaking crack in one of those spider web etchings near the seam where the outer rim meets the spoke, not at the bead. One wheel the leak was near the valve stem and the other wheel was about 5 o’clock to the valve stem. First time I’ve ever had a cracked rim on any vehicle.

that's a little worrisome , I have heard of more then a few cracked 8 lug 110 psi wheels . Low bid China crap! that was the single biggest reason I put Alcoa wheels on my trailer with a 17.5" tire upgrade , American made! rated at 6000lbs a wheel. You would think the NTSB would have tire and wheels on there watch list . Makes me question if mine are good to sell , I have the same spider web look on the finish?