> I'd factor in huge improvements in road surfaces. I've had guys INSIST my
> PX-10 is a "touring" geometry and not racing! That shows you how angles, top
> tube lengths and fork rakes have changed as road surfaces have improved. How
> many modern cyclists even know why racing cyclists wore goggles up to about
> the mid 1950s?
Another difference is how pro races work, and how the format has changed. Stages of the Tour de France have gotten shorter, but they've also gotten faster. When it started, support wasn't allowed at all; now those guys don't even take a piss without help. They don't have to ride for nearly as long at a stretch, but they have to go a lot faster.
> When you look at old bikes, you begin to realize that much of the
> technology changed because riding styles changed, and on the other
> hand, riding styles changed because technology changed.
Those are the things I'm curious about; after all, it's always a two way street. It does make me speculate about how the geometry or ride styles from different periods might suit different riders or body types in different ways. Seat tube angles, for example, will vary partly with the usage, partly with style over time, but partly with the biomechanics of an individual rider's leg and the requirements of what they're doing.
I'm not so much interested in any one period in particular; just whatever periods people care to talk about.