Originally Posted by WhyFi

Are those early brifters on that bike?



Any easy way to gauge additional tire clearance is to use some hex/Allen wrenches as feelers - check all of the tight spots: on the sides between the stays/fork, between the top of the tire and the fork and the seat tube, etc. Generally, manufacturers recommend 4mm of space, on top and to each side, for debris clearance, wheel flex, etc. Keep in mind, though, that some tires are sized differently, and one tire in a 25mm may be as large as another in a 28mm, even if it's from the same manufacturer. The current trend is towards wider rims, which puffs out tires a little more than older, narrower rims, so we're seeing that recently released tire models, of a given nominal size, are a little narrower than those from a generation or two ago.