My rb has 23mm at 115psi (and I let it fall to around 90psi if I'm real bad, oh the ride is so good) and my cx has 32mm 80psi tires (oh boy this bikes is so comfortable after the rb). Aksium on rb, DA22 on cx. My preference is rb whenever possible, cx on those odd occasions (full fenders, rack, rain and snow conditons). I might try 25mm on my rb one day, but so far I'm not bothered.