Heres a tip. Check your rear shock settings for your two up weight. Cupping is a symptom of the front tire being cyclically loaded and unloaded. Yes, PSI plays a part, but if you're over weight for the setting of the rear shock or the rear shock is too stiff, you'll find the bike will see saw through a turn. In turn, you will not lean the bike over far enough for fear the front will wash out and the bike will use that see saw weight transfer to grind the heck out of your front tire. Rear can do it too. Cupping is a function of the turning mission of a front tire, however if it is bad enough to blow through a tire in 4,000 miles, then theres a problem. I've heard and confirmed myself that most touring frames go up to 20,000 miles on a front tire. I got 19k.

If you've got the originally air shocks on board... those are your culprit. Air them all the way up OR get a set of progressive 944s in either standard or HD spring loading depending on your two up weight.

Hope this helps.

 

That's funny....Same thing here, I have a set of those ready to go on as soon as it gets warm.
I wasn't overly impressed with the CII's on wet roads.

 

http://w6rec.com/why-motorcycle-tires-scallop-or-cup/
Google “motorcycle tire scalloping “
Read some of the articles and get back with us.

 

It could be balancing. Take all the weights off, and try about 3 oz of ceramic balancing beads. They go inside the tire through the valve stem. They can be found on Ebay pretty cheap. The tire always stays balanced no matter what the condition, only needs to be done once, and are re-useable from tire to tire. I use them in a semi-tractor, my pickup truck, and on my '17 Limited. I took the stick on weights off, and put 2-3oz in the front 3-4 oz in the rear.

 

I'd say try beads too. But they will void a tire warranty if that is a concern to you.

(Having had a tire replaced under warranty in the past year, I ran into this issue)

 

How's the oil in your forks? If the damping isn't good the slight tramping that tends to result will cup a tire.

That said, I've had bikes and tires that simply were darned determined to cup, no matter what I did.

 

No one has mentioned checking wheel alignment front to rear

 

Check wheel for run-out/out of round condition with a dial indicator.

You say you ride 2 up 80% of the time. If you're loading the bike near it's rated loading, you may need heavier front springs/suspension. Also, try running air higher air pressure.