It's just from memory after 10-years of racing. Although I've only done three cat-4 races, they are very similar to collegiate-C races. If you're fortunate in your area to have a womens-3/4 race, it'll be slightly slower in speed to a men's cat-4/5 race. The womens-1/2/pro race are similar to mens-3 races. Although it's usually the same small group of women winning these races all the time. They can usually do the mens-1/2/pro races without any problems.

The thing that a lot of beginning racers don't realize is that bike-racing is about competition, NOT performance or fitness like most people familiar with track & field events, marathons, or swimming events think. You DO NOT run the course against yourself and the clock and compare times with others. It's more like picking up some boxing-gloves and getting into the ring with another competitor. It's more like wrestling, fencing, football, soccer or chess. Winning is about directly interacting with the others.

So focusing on average speeds really isn't any indicator or predictor of how you'll do in a race. I've seen a tonne of super-fit athletes come in from other arenas of fitness sports like running or swimming and they can drop just about everyone on the training rides with blistering solo time-trial speeds of 27-28mph. Yet in a race, they're instantly off the back, or they crash and break bones; a lot of them quit early on in frustration.

Bike racing is about mental-strategies and tactical-games. If you're good at chess or Risk or any of the warfare games, then you'll be familiar with the kinds mental posture that's required for bike-racing. Bike-handling skills is an often overlooked training requirement. Learning to visualize the fastest line through a corner and actually being able to manuever the bike on that line precisely is critically important. Sometimes in a race, you have to ride the gutter with your chainrings rubbing the kerb because someone's got their shoulder leaning on you pushing you down in the corners. Other times, you'll be in the middle of the pack going around a corner at 30mph and you'll be rubbing guys on both sides with your shoulders & elbows. At the end of a race, frequently they'll be guys shoving you off their teammate's wheel in setting up for a sprint. They'll pull off way to the other side of the street and dive back, slamming into you like a linebacker. Bike racing is more similar to combat-type sports such as boxing, wrestling or karate than it is to running track, marathons or swimming.