Originally Posted by
JoeyBike
If you regularly see your speed hitting/exceeding 25 mph on the flats, then full roadie kit for sure. Otherwise it's a waste of money and kinda hilarious.
I don't see what speed has to do with it. Aerodynamics is a small part of it for most recreational riders. Sweat management is key. I sweat buckets regardless of the weather. I've ridden in humid weather in a tee shirt and had trouble peeling it off after. This doesn't happen with a bike jersey.
In cold weather cotton tees will get wet and make you cold. Ever hear the expression "cotton kills"?
Jerseys have rear pockets for carrying layers, food, whatever.
And shorts or bibs are chosen for the same reason. Sweat management helps with comfort. I can't average 25mph but I wouldn't want to spend 6 hours on the bike without Lycra shorts. And I wear the same clothes on the mtb as on the road bike.