For a little variety, you can use the 60 minute Delta Ultra Deep Standalone Meditation which takes you down into Delta and holds you there for an extended period of time. If you can stay awake during this entire time, you will have some amazing meditative experiences. (If you fall asleep, don't worry! It's natural and with practice you will be able to stay awake more often.)
A study published in Electroencephalography and Clinical Neurophysiology by Paul Williams and Michael West in 1975 examined the brainwave states of people experienced in meditation while using photic stimulation, and another study by Leonard, Telch, and Harrington in 1999 examined the successful use of brainwave entrainment techniques for attaining meditative states in subjects.
Why do you like to do these things? “I can escape from stress on my bike. My time on the bike gives me time to problem solve and consider all sorts of things. There are no interruptions from technology so it’s a peaceful time for me. I get to enjoy just being outside. This will sound crazy but sometimes I can ride for miles and not even remember the actual riding since I was ‘lost’ in my thoughts.”