What's the difference ?
 

285/75/16 vs. 295/75/16

what is the difference and if i can fit 285's then could i fit 295's ?

here's one of many tire size calculators.
http://www.1010tires.com/tiresizecalculator.asp

just off the top of my head, the 295's are 10mm wider (about 3/8") and a smidgen taller. they should fit fine. some people are able to fit 305-315. if you get rubbing at full turn, adjust the turn stops on the knuckle.

well my original plan was to go with 315/75/16 on my oem rims but someone told me that those tire wont fit on my rim?

315/75/16 will fit on your oem rims, although they really need a wider wheel. but they would fit and with a 2.5" spacer in the front, they probably would not rub either

Whatever you do, POST PICTURES!!!! :D

To see what size tire fits what size rim the best bet is to go to the tire manufactures web site and see what the recommend rim width is. In most to all cases it's a 8.5 inch wide rim for a 315 or 12.50.