Widest tires I can run?

Anyone know the largest width I can run on a 01-04 taco WITHOUT sticking past the stock fenders?

Edit-
I should mention I'm currently running 1" spacers right now. I'm trying to find a balance between diameter and width. I'd like to find something around 34" dia. but I'm unsure what width I can get that won't rub the frame and stay underneath the fenders. I'll be running stock 16" TRD alloys. What's the backspacing on these? Am I making any sense?

Edit again - Fuck it. These tire sizes are a cruel joke. 255 is the only one that comes in 85? What the hell is with that? Should I just go with some skinny 255/85/16s or go all out and get 315/75/16 and get larger fenders? Looking to hit lots of rocks, maybe some mud here and there and highway driving...

This is stock 265/70/16s



This was the 33x12.50s w/ 4" BS but it rubbed the frame so I later added the 1" spacers

 

So you are wanting something between a 12.5" (which is basically a 315), and a 10.5" (265)?

The 255/85 and the 315/75 are vastly different sizes in both width and diameter. The 255/85 is a 33x10 and the 315/75 is basically a 35x12.5.

If you are going to be offroading and are also worried about rub, I'd stick with a 285/75/16 max, which is a 33x11.5. That would also get you an intermediate width near the fenders that you are looking for., at least according to your pics.

 

I understand they're vastly different. I just couldn't decide if I should just go mediocre or take the 'go big or go home' mentality including glass fenders which is what I'm leaning towards. I guess I was just thinking out loud haha

Edit: I'll cut the shit out of the fenders and the firewall... just don't want it rubbing the frame. Since I originally posted this question, I think I've decided to stick to 15" wheels since the price difference it ridiculous.