Functional Threshold estimate...

root

Ergoman

I'm not familiar with your particular stationary bike, but based on experience with others I would guess that the power information that you're getting isn't too accurate. I wouldn't rely on it as a device to determine your real world FTP.

OTOH, a stationary bike can be pretty consistent, and if you always use it as the standard reference for your performance it can be a useful training tool. Knowing consistent and repeatable numbers is the key to sucessful training, absolute accuracy is of lesser importance. After all, FTP is just a number that represents effort. If you can represent that effort with another number, so long as it's consistent, what's the difference?

daveryanwyoming

As Ergoman said, the indoor bike may or may not be accurate, but it is probably repeatable which is more important anyway. Either way, a lot of folks struggle to produce the same power indoors as they typically produce when training outside. Good cooling in the form of a big fan can help as can practice especially for trainers with small flywheels and their low moment of inertia. Some of it's psychological since it's just not very much fun or very interesting to ride in place for an hour or more at a stretch.
That's real typical for ergometers that hold constant power over a range of cadences. The force requirements decrease with increased cadence which of course is just the opposite of riding a real bike outdoors since real bikes don't hold constant power all by themselves. I find my intervals on ergs tend to higher cadences than I often use outdoors. Funny thing though, my long intervals outdoors often average 90 rpm or so but my time trials usually average100 to 110 rpm just like the erg workouts. So maybe the erg is a better representation of my time trial efforts after all.

-Dave

sogood

I am in the same boat and train similarly, especially for wet days. The constant power offered is consistent with the goals of power training. Fortunately, our community's stationary bike can dial up to 320W, so there's room to grow for me but no ideas as to how accurate the wattage readings are. As long as there are improvements over time, who cares?

__________________
Morphed Bianchi Camaleonte IV 2006, Ridley Damocles 2006, Garmin, Mac