I'm on 700 x 25 on my Allez, I think the stock tyres were also 25s'
I still havent quite got the hang of this stuff!
Picke dup some folding sale tyres and inner tubes (from the bargain thread ) and I think they are 700x23 I think. Anybody know if 700 x 25 and 700 x 23 are interchangable provided the sizes of tyre and tube match - if you see what I mean? On the same wheels obviously