now, this is by no means the be-all, end-all bible for bronco tire fitment. there are all sorts of variables that come into play. This post is being created in order to cut down on the repetitive questions of what size tires can i fit with X amount of lift.
31" tires: these generally come on the truck stock. no fitment issues, no rubbing
33" tires: these WILL fit with no lift. the fit will be a touch snug, but you can either trim the edges of the bumper, or use washers as shims at the bumper mount. you can run a 3" body lift if you like to clear these tires, but its not necesary. slight rub will be encountered on the radius arms,depending on the dimensions of the rims
35" tires: these will fit with a 3" body lift at bare minimum, but its not advised for wheeling. large amounts of contact will be seen between body and tires. 4" suspension lift will provide better clearance, with a 6" suspension lift providing the optimal clearance while mainting a good center of gravity
38" tires: these can be run with 6" of lift and healthy amounts of fender trimming. its better to run around 8" of lift in order sufficiently clear these tires. once you get up into this size tire, you will be seriously taxing your stock running gear and drivetrain. a built up solid Dana 44 and rear 9" can handle this setup OK. adding a stonger rear, such as a Dana 60, is a safer option. depending on your typical wheeling enviroment, a swap to one ton running gear may be necesary to minimize breakage. for more information on this, refer to the Fullsizebronco.com message board, SAS forum.
anything bigger than 38" is going to be totally custom, and you really should upgrade to one ton stuff
Yep, 31x10.50's without any rub or fender contact. Try a search, there's plenty of info on tire size and fitment. I have 33x12.50R15's on 15x10" rims on my stock 86 Bronco with no rub, but each bronoc is unique, as are year models. Best suggestion is to try a 31/32/33" tire-rim combo on YOUR Bronco, and check the clearance. Do not forget the fact that a larger-than-stock tire will affect your final drive ratio, which affects mileage and the speedometer. You will want to know your axle gear ratio, as well as the engine/tranny/t-case model to figure the change from larger/taller tires. There are formulas to figure ear ratio for a tire size as well. JSM84