Did you ever try? I have a 48 and I haven't tried yet? I have the SL. I have to change the tire today for a century tomorrow and the guy in the LBS did want me to get a 25 but I was dithering and got the 23 in case I couldn't get it on. I got the cont 4000 so hopefully these will last longer than the rub pro. But I would like t o switch on the next tire change.Thanks for the comments on smaller sizes. I have a 48cm frame so I may be in trouble. I suppose I could always do 25c front and 23c rear.