Will Rims Fit on Tires?

I have rims that are 15x7, and want to purchase new tires for my X, probly 30x9.5 or 31x10.5, and I wanted to know if I would be able to fit either, with no problems.
By the way, I have no lift or anything on my truck atm.

 

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Dead Link Removed

First post, near the top of each gen's section is the biggest tire you can fit with no mods on a truck.

 

[dondiesel444]

are those 15x7's the factory size?? I have had 30x9.50's and now 31x10.50's on the factory rims and they are fine, the tires don't buldge out or anything, they look great!!