Its doubtful that you can get an accurate number. There's a few factors here, but 1. Its hard to truly motivate yourself to crush it for 2 hours. Could you have done 5 more watts, 10? 15?
You can rest assured that your FTP is going to be at least 10% greater than the number you got.

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You could probably divide by 0.9 and get pretty close for most people. A really strong pro triathlete might manage as high as 0.95 for 2 hours.

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TrainingBible Coaching
http://www.trainingbible.com

A WAG would be ~ 5% greater watts for your FTP. Many athletes see ~ a 5% drop off with double the time.

YMMV,

Hugh

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Genetics load the gun, lifestyle pulls the trigger.

I know it's not gonna be accurate, but it's a ballpark. Both of what you guys suggest fall in a similar window. I had to go really hard at it and could have squeezed a few more watts at best so it was a strong effort.

Power curve. Algorithm. If can estimate FTP from 20 min then can estimate FTP from 2 hour. Best do 60 min be sure.

That was what I thought too, but all I saw (before this thread) were methods to extrapolate FTP from shorter efforts. Where do I find these power curves? I'm OK with the approximations found in this thread so far.

This is pretty spot on! Current FTP of 310. Rode Vineman (2:22) at 280 watts.

D

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Team Every Man Jack

http://www.teamemj.com

If you have decent power meter analysis software you can load up your mean maximal power chart and see your own power duration curve.

Golden Cheetah can even take a stab at extrapolating it for you, if you have enough data.

some more info:
http://austintriathlonstore.blogspot.com/...mal-power-chart.html

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
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Freelance sports & outdoors writer Kathryn Hunter

Yeah, looks like it would be the most "scientific" method, I'll keep it in mind. I think the data they collected would allow this kind of analysis so the first step would be to actually retrieve the data (it was a 46.6 miles course, very rolling). I'll try to ask if the place where I took the TT actually have that kind of software and get that "MMP" chart.


Edit: now that I'm reading it that link, the place where I did the TT should have 5 set of data for me on that course. Hope they kept the files.