I train with power on my Peloton using Power Zone, HIIT, and climb workouts. Without a power meter on my road bike, I had no idea how to pace myself.
Using Ride With GPS time estimate, I aim for this formula:
Average Power % of FTP = 100 – hours * 10
The idea behind the formula above is based on the fact that you can theoretically ride at 100% of your FTP for 1 hour.
Ride With GPS is reasonably accurate with the estimates. For example, if it’s telling me a route will take me 2 hours, I aim for 80% of FTP as average effort, a Power Zone 3 (tempo) effort. If it is 5 hours, I aim for 50% of FTP as my average, top of zone 1.
It does not mean I ride the entire time at that power level. That means that I allow myself higher efforts when the road is steeper and that I am mindful of my recoveries and preparing for what’s to come.
The formula I am providing here is far from scientific, but I make a mental note for myself as I plan my rides. It works for me.
It is possible that using my formula, I end up under-performing. I honestly don’t care. My goal is to complete long endurance rides in a reasonable amount of time while enjoying the ride, not to prove anything. It works for me.