I have an 8528ikws (2015). I towed it home 100 miles with my 2011 F150. I have since purchased a 2011 F250 diesel with 20" factory wheels, mostly because of the payload specs as the F150 5.0l towed the 5th with no problem. I was more worried about being over weight on the rear axle. The F150 was stable and braking was fine. Power was no issue at all. I got a great deal on a low mile f250 so I traded. My comparison measurements between the F150 and F250 showed the top of the bed rails to be almost the same on both trucks.
I didn't measure bed height from the ground but I believe that dimension to be very similar also.
I had zero issues with clearance on the F150 and since the top of the bed rail dimension is virtually the same I am confident I will be fine.
So far every reply has not addressed the bed/rail clearance question. If any of you have the two exact same vehicles F250 w/20" and 8528ikws or similar 5er. Is your clearance ok without modifications?
I'm interested to hear comments from others with similar setups.