47 on the road... and it has 1.25"x26" 90psi tires, they roll pretty well - The last few times I did the 47 loop on my road bike I was 10 minutes faster, so it is a bit slower. In addition to the weight and rolling resistance, it may be because having a cyclometer makes me constantly race myself, and I don't have one on the mtb so I usually just go at a steady pace.. and also, the tallest gear on my road bike is 42x27 and I know I use an easier gear for a couple of the hills when I'm on my mtb so that probably costs a bit of time too.. I've been riding it lately because I'll be using it for a MS150 ride for the more relaxed gearing and riding position, plus I put a rack on it for a bit of carrying capacity.