Originally Posted by
Carbonfiberboy
We hope the OP and arguers are all using GPS for speed. If not, the OP would certainly notice a large speed increase from the 25s. Those 28s are very tall tires.
I've been enjoying 23mm tires on my 23mm (outside) deep rims. They look fast and maybe they are. Certainly doesn't hurt on descents. It occurs to me that perhaps pros are going to 25s to match their 25mm rims. Or 28 for 28 rims if there are such animals.
I dunno, my bike computer says I'm going slower with the 28's, having not gotten around to changing the setting yet. About 1/2 mph less than I think I'm going.