I started exercising 4 weeks after a C section. I was doing high impact aerobics, not cycling, but it was still pretty strenuous. I didn't find the recovery to be that bad. I started walking after 2-3 weeks. You will be tired from just having surgery, so start slowly and listen to your body. Most doctors clear you for any type of exercise after 6 weeks. This was a long time ago, but I don't think too much has changed! I had two vaginal deliveries after the C, but i think doctors today are too afraid to try this.
Everyone is different.