Quote Originally Posted by CA_in_NC
I feel like they're not having fun if they're "looking after" me.

Gotta love group dynamics...
This doesn't change no matter how fast you get. It's the price you pay for the many benefits of riding in a group (getting faster, better bike handling skills, finding new roads, etc). No matter how much I insist, the guys won't drop me. They either slow till I catch up, or send someone to pull me back after a hill.

In my experience advertised speed has little or no relation to actual speed. Look at their legs and bikes, if they have 2% bodyfat and $5000 bikes, count on over 20mph (even if they're "going slow") average (including hills). This can be extrapolated downward.

If you feel bad about slowing people down, know the route, and make it clear that you don't mind finishing the ride solo. If they stick with you, that's their problem.