I've been struck by how remarkably similar all the bikes are in the TdF. I know, some will say that companies have all perfected the best possible design, but I wonder if there's more to it.
Every bike seems to have the handlebars in exactly the same position. No one has a different type of handlebar. No one has aerobars on a non time trial day, and there are no bikes with a different geometry.
Are there some rules about this?