I can't do 28c tires on my Raleigh road bike. No touching unless my tire picks up dirt, which happens every so often. then it rubs the brakes, brake bridge and seat tube. (Stupid tight-clearance racing bikes, proving purity of the rider by their inability to be adapted for other things.)

Short answer was, in my case, it was really annoying to have rubbing on the underside of the calipers every time the tires picked up any dirt. I'm back to 25c tires now.