Postwar Motorcycle gear

Going through and cataloging which of my old sketchbooks I want to put on eBay for sale first when I came across this collection of study sketches I did years ago for a color piece that I never got around to completing. Sigh, maybe some day but not today.

The piece in question was to be of an all feline anthro motorcycle racing crew at one of the Isle of Mann races in the 1950's. The added twist was that rider would be Manx who was riding a Norton Manx motorcycle, which was one dominant models during this time period.
The thing I found so amazing was how much more sophisticated modern motorcycle gear is, and how slowly gear developed in the the first 30 years after the Second World War. It was a very subtle evolution from 1930's through even the mid 1960's.

The other thing I found amusing is how certain shapes and forms will repeat themselves throughout history. As I started to study helmet designs from the period I was surprised at how close they mimic the designs of steel skull caps from the Middle Ages. I don't know if motorcycle helmet designers were inspired by these earlier helmets, or whether it is a case of convergent evolution but I found it interesting.