I really like Michelin Pro Race-4 tires in 700 x 23. I run 115 - 120 psi rear, 105 - 110 psi front. These tires are slightly larger than other brands. I think the 23's are about the same size as 25's in Continentals. When I tried a Michelin 25 mm on the rear of my C-50 the brake bridge was cleaning the sand off of the tire. The Pro Race are relatively light multipurpose road tires. They are soft and feel sticky in high speed curves. They also roll very well. I tried riding Vittorias on my friends Colnago and they felt heavy and sluggish but they were the puncture resistant type and I'm sure they make lighter higher performance tires. I should try them.