A lot of people trim an inch or so off the end of the rails and then bend or cut the pinch seam to not have to run as long of bump stops. I cut 4dr rails down to fit my 2dr, and haven't put the end caps back on yet for that very reason.
As wTheOnew pointed out- it has a lot to do with bumpstops.
I had a 2.5" BB which included extended bumpstop. I ran 35's without cutting the seam or rail. The tire did not rub at all- when stuffed, the widest part of the tire was still below the seam.
Later I switched to a 2.5" lift, which did not have extended bumpstops, and used the stockbumps instead. With that setup, when the 35's fully stuffed, the widest part of the tire did indeed rub the seam. So I trimmed about an inch off the seam and rails.
I put rubi stk rock rails on my Sahara. With my 35's, I could not fit my smallish hand between the tire and the rail end. I read somewhere, that under compression, the tire rotates back a tad, and that the room is not an issue, BUT why bother....
It is super-easy to trim with a saws-all. I trimmed 2" off , slightly angled and then silicon-gasket'ed the plastic caps back on. ( blk silicon ) While I was down there, I went ahead and saw-alled the body crimp in the rear wheel-well too to follow the contour of the well/ tire. Then i sealed that cut with the silicon-gasket stuff. Came out great.
The clearance between the tire and body/rail is just too close unmodified if you ask me, especially considering the ease of modification and the downside of a damaged tire... @ 35", they are wayyyyyy too expensive to risk it.
'09 JK Unlimited Sahara ( sold )
'97 TJ (sold )
I think thatís what I need to do also. It just looks like they will hit. I need to go out and flex it to see if it will, just havenít had a chance yet. Or maybe I should just trim them and be done with it.