Originally Posted by
robabeatle
^Wrong. And indoor numbers do not translate so easily to the out of doors.
This can absolutely be done on the road. You have the right idea. Just go out and do it. In two months or so, go out and do it again. In between, follow a structured plan which will be very effective in bumping up FTP, see Friel or the Racing Forum. To be sure, a 20 min test will only give you feedback about a narrow power bandwidth. If you really want to learn about your riding, do shorter tests too and longer as well. 60 min, 10 min, 5 min, 1 min, 30 s, 15 s, 5 s.
Have fun.
One can certainly estimate FTP any number of ways, but unless you live somewhere where no one uses the road, the wind doesn't blow, and the road surface is perfect, using a stationary bike is much easier and gives cleaner, more accurate numbers that one can really build a precise training plan on.
Sure, riding the road with a power meter will give you power numbers, but I'd bet that virtually any rider will post higher average watts on a stationary (studio power) than actually riding over the road. One can focus so much better on a stationary, and that makes a difference; isn't that what you're getting at when you talk about 'translating indoor to outdoors', the fact that indoor numbers are almost higher for a given period (the exception being climbs, perhaps)?
And isn't that what you really want to know: how hard can I go when I really dig in and get all the power out?
I do both, studio power and road power, but anymore, it's really only studio power that determines the training regimen, because it's so much easier to see what, exactly, is going on when you look at the numbers.