Originally Posted by MikeRides

Is there much of a difference between 700x25c and 700x28c size tires, for road riding? My bike came with 700x35c tires which are well and good riding around town and on a bike path but for longer road riding I've thought about going down a size to pick up more speed. My LBS recommended the 25s but because I'm not giving up unpaved bike paths I thought about just going with 28s. Assuming that's going to make enough difference from my current 35s. I'm getting tired of pedaling at nearly full power and only taking 2 seconds of rest/no pedaling to come to a crawl on flat pavement