One of my favorite group rides around Chicago. Ten27 ride start every Sunday at OtherBrother Coffee Shop at Evanston 8am. Definitely nice speed and with few sprints at local short hills, everyone is riding safe and work hard.
Today ride of full of breakaways, you can check my data from power meter.
Entire workout with nice 0.90 IF for 2h 46min a lot of breaking away
2 men breakaway 1.00 IF 30 min
Solo breakaway 1.05 IF 17 min