I have 295/75r16 BFG KO2s, slightly bigger than a 33, they measure 33.4" tall. They will barely rub the top of the underlip of my limited flares at full stuff.
I had to grind the pinch-weld back a bit though to clear at full lock/stuff, but not enough to warrant any welding:
When I had my stock bumper I had to trim the inside of the limited bumper flares a little as well.
For the rear, the tires will rub just barely on the back of the underlip of my limited flares at full stuff. The mudflap bolts that poke into the rear wheel well did rub a little at full stuff, I just removed those (the mudflap stays on just fine without them).
I'd say 295s are the largest tire size you can be run without a body lift and only minor trimming.
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1999 4Runner Limited - 5VZ, 4wd, Factory E-Locker, Multi-Mode, 5-speed swap, Armored, Icons, 295s (
thread)
2001 Tacoma Xtracab - 3RZ, 4wd, 5-speed (Daily Driver)