From personal experience i put a 34 on my 06 1500 with a leveling kit on but before hand the biggest i could fit on mine was a 275/75/17 but i had to trim a very little bit. I found this website for you( http://www.tacomaworld.com/forum/tirecalc.php) its pretty average for the sizes of tires and you can compare them to your old tires and see what a visual will look like.
