2mm clearance between the chainstay and the rear tire
Clearance is clearance.  It will work fine until your wheel goes out of true, or you ride in conditions that produce 2mm of extra width on your tire (mud, snow, etc).  Or alternately some combination of the two.  Depending on your frame material (I am too lazy to look yours up, but I'll assume steel) it will probably rub on almost every ride at some point when you flex the frame enough for it to touch.