The rear seat stay’s are a little wide but it’s not a problem. When I look down while peddling there is 10 to 15mm clearance. You do catch them from time to time as you would on any bike. I run flats with 5 Tens. How tall are you Pawsy? I’m 5’10 and the large fits me fine,had a medium ordered but the large came in first so took that.
I’m 5’8″ short legs. I rode a SC Bronson large which comes up similar to medium Zesty. The large Bronson reach was still shorter than Zesty medium! Bronson felt very much like my 2010 medium Zesty reach wise