I ride everyday if I can or at least run/race walk. I ride a lot of miles usually 50 a ride. I need at least 7-8 hours sleep sometimes more. I have no problem with naps at all take them at all hours during the day. One think I do though is I am early morning person. The deacon gets up with the Monks between 4-5 am most of the time. I have even lately been getting up as early as 3:30. I don't sleep for long periods without waking up always have done that. I don't get up but wake up at least every 1 or 2 hours at night.
I am not sure if bike riding does it but I also think it may contribute to the weirdness factor of being active. I do know that overdoing it and getting completely wiped out on a ride can make me very tired but does not mean I will sleep well at all usually worse. Sometime I go out at 4:45 am do a 50-60 mile ride come home an eat a huge brunch and then nap for at least an hour. That is all before 11 am.
I might add I can do that as a widower and retired. Even when my wife was with me we got up at 5am. I think naps are great and from what I gather ok for a person. I say if you are sleepy, take a nap if you can. Some times I fall asleep at after dinner at 7 pm and then get up at 10 and play the guitar for an hour or so and go back to sleep. I am a jazz guitarist in hiding at the moment.
One goal I have coming up as the morning sun gets earlier is to go out by 4 am so I can do a century and be done by 10am. I don't normally do centuries as such but doing one this way I get the rest of the day with a lot left.