Just bought the FX4--Daystar 2.5" leveling kit is first. After that, how large a tire can I run, and can I fit a 16" rim (specifically Ultra 50/51) on the stock drivetrain/brake set-up?

 

You can't fit 16's on the new F-150's. I'd suggest an 18x9 inch wheel with 325/60-18 tires.

 

Do you have the factory 17's or 18's. Mine came with the 18" upgrades and the Goodyear AT/Ss. I sold them and bought a set of factory 17's for 100.00 and some new 315/70/17 BFG ATs for 400 from discount tire. Of course, the tires were take-offs from an H2 they were putting 22's on....his loss my gain.

Anyways, you can run anything up to the 35" range with the 2.5".

BTW, post some pics of your truck.

 

Sorry, posted to new topic.