Tires: Uneven tire wear, chevy tahoe, alignment problem

Question
I was wondering about my 1999 Chevy Tahoe and my uneven tire wear I am having with it. It seems to be mainly on the front end and even more so on the passenger side more so than on the drivers side. It is cupping real bad and then wearing out the outside edgo of the tire to the point wear its tread is gone. I bought this truck and didnt have that problem and then I take it and get it aligned at the dealership and another place where I bought my tires and now its a disaster and cant seemed to be fixed. Do you have any idea what is going on here? Please let me know, I would appreciate any help you can provide.

Answer
Your alignment is way off.
You need to go to your dealership and have them fix the alignment.
Now, just because you get it aligned, does not mean it is correct.
What you need to do is a must.  
You must replace the tires, both front before you have the alignment done.
Then the alignment should work.
However, talk to the dealership first to make sure it is a alignment problem and not something else.

Good luck,
John