Will they fit
 

Ok so I was wondering if I can fit 285's on stock rims. Will I have to trim some or crank up my t-bars?

I am running 285/75r/16s on my stock Dodge rims just fine

yep they should..
my truck is a dodge with 285's

a friend of mine has a gmc like yours stock hight and wheels with 285's

Thanks guys, I need to replace my tires real soon.

yeap the will fit.

Might have to do a little cranking or trimming.

Yep, little cranking and a little trimming.