Little rear rotor clearance I have just test fit my wheel on a Litespeed T5gravel that I'm building and I see there is less than 1mm of clearance between the rear rotor and the chain stay. The rotor is currently a 160mm avid Centerline, and I'd happily move to a 140 but from what I can tell you can't go down a size with this frame (the brake mount is part of the frame and seems to be built for 160). 

Maybe it is fine but it is so close it seems like it will start rubbing even from thermal expansion. See the pic for what I'm talking about. 

Any advice?
I think that will be okay.  Have a look if there are no spacers behind the rotor mount bolts - or if it's center lock see if there is a spacer behind it as well. 

Removing these may help.