Hey there. Hope I'm posting this in the right section, newbie here, so if not, apologies ;-)

I have a 2wd '03 Sierra and I'd like to put some wider tires on it. I have a 6 lug wheel but I don't know the width of it. I would like to know how wide a tire I can go with that will fit on the rim and not rub when I turn the wheels to full lock. Anyone know?