That's a good question. I really don't know where the 23'' or 25'' is measured to and from. What I can tell you is that you can't go wrong with the longer forks. They can always be shortened. The measurement you need is axle to bottom of triple clamp with forks compressed. If you have at least 13 1/2'', a 26'' wheel and tire will fit nicely. If you're going to use a front fender, then you have to get creative. I used 3/4'' or 1'' spacers to keep some of my forks from hitting the tire and stilll had about an inch or so of travel.