A spandex-covered recreational cyclist. Possibly a cross-over from motor-cyclists.
However, in cyclist terminology, this is a recreational cyclist generally wearing lots of spandex, lycra, or just all-around racing gear as well as a multi-thousand dollar bike. Most often middle-aged. Generally they are happy logging only a few hundred miles per year on said bike. They are generally OVERLY defensive cyclists and chastise younger cyclists who choose more aggressive traffic behaviors to remain safe such as retaining road space in order to not be pushed off the road by motorists.
Wow, this cycling event has so much spandex it's like a squid orgy!