Originally Posted by
Redbullet
Some materials on the internet say that pros ride 25 mm in most cases, but I can’t know where the truth is.
You just need to read current trusted sources of info and look at the spec of current £10k cutting edge race bikes.
Some pros might still use 25 mm tyres in some races, but 28 mm is now pretty standard. Sometimes they use 25 mm front and 28 mm rear. For the cobbled classics they use 30 or 32 mm even with hundreds of km on normal paved roads.
Another clue is that the latest generation of aero wheels are often optimised around wider tyres - usually 28 mm.
Your new race bike came with wider tyres as a reflection of what the pros are now riding. I’m pretty sure they are not trying to make their bikes slower.