I suspec t more to do with that most of the race is actually on smooth tarmac, only certain sections are on cobbles. The roads are very narrow, making it difficult to get to a team car to change bikes. Though I believe a lot of the riders run 25s.
That bianchi looks like its running 21's, it is a display pic though.
That bianchi looks like its running 21's, it is a display pic though.