I have found that computer manuals differ in what they use as circumference measurements. I have had a few computers, Cateye and Sigma, that have 2096 listed for the circumference measurement and some that show 2111. I ride on 700x25 Gatorskins and using the roll-out method with the tires inflated to 95 psi (what I always inflate them to) I get a circumference of 2105. I'm not sure how much more accurate it would be if I used the 2096 measurement vs the 2105 or if it even matters that much, but I just use 2105 and I don't worry about it.