Back Rack Side rails and toneau cover
 

I just got back into a truck from having an Explorer Sport for a year. At my work site there is a truck with the standard back rack and the bed rails. I want to put a cover on my truck, probably a retractable or roll up type.. The only hickup is the Back Rack Rails have a plate that goes down into the bed to completely cover edge. Looking at most of the covers they only cover a very little of the bed rail and simply clamp to the inside of the bed rail. My question is somewhat silly because Back Rack says you can not have a cover with their bed rails but I'm not sure why. Is it because that lip they have takes up to much space and the covers won't function properly or is it something else that i am not seeing. Most of the covers I have looked at require a shim of sorts because the ford beds have a taper to them. If I don't use the shim wouldn't the lip from the Back Rack rails act like a shim? Any thoughts on this?

Installed TracRac with full length bed rails with a BAK Revolver X2 cover. Shim? Why?
There are several cover/rack combinations available HERE.

EDIT: I goofed. I didn't realize the OP was talking the brand "BACK RACK," so my initial reply is not applicable.

The BakFlip MX4 (and G2 and others) also do not cover the stake holes.

https://cimg2.ibsrv.net/gimg/www.for...e1839b7c83.jpg
https://cimg6.ibsrv.net/gimg/www.for...1443c1c276.jpg

The lip does hang over the inside of the bed rail too much if your talking about these
https://www.carid.com/backrack/full-...iABEgKN7vD_BwE.
I did try a set. Amazon easy return

That is exactly the answer I was looking for. I thought about cutting the lip off but I'm sure it's there for a reason. I guess I'll keep looking for a solution