As I mentioned, if you go to tirerack.com, put in your vehicle information and it will show you what tires will fit your truck. It even gives you the option of what they call 1 plus, which shows the next size tire.
Although I drive a PreRunner, which is a 6 lug truck, I did a little research before deciding which truck to buy. What I found was that the largest tire on a stock setup was the 235/75 that I mentioned.
You can also go to tacomaworld.com, then view their 5 lug thread and find a little more info.