virtual power for sufferfest

Peripedal does it, but it costs similar to TR, and after using both extensively, TrainerRoad is hands down better - on everything. 

The free download GoldenCheetah has a 'train' feature that some people get to work, but I've never gotten it to work. But that's a start - GC itself is a great program for power data.

TrainerRoad is BEYOND WORTH IT.  They have workouts specifically designed for each Sufferfest video.  I can't express enough how well this works.  Not only that, periodically they have special "events" like the 8 Days in California challenge going on this week.  Sign up for a few months and just try it out.  They give you the ability to suspend your account with no penalty.  For example, you can sign up for only the winter months when you ride indoors alot and suspend the account during the summer when you ride outdoors.

I ride 95% of my riding indoors year around due to time/family commitments.  There's no way I could do it consistently without TrainerRoad.

Part of the TrainerRoad/Sufferfest integration is the workouts they give you.  As you're watching the video, you'll see the whole interval coming up on the screen.  You gotta push the watts (keep the bar "in the green") for the duration of the interval.  The scale of the interval is based on your FTP which there is another TrainerRoad workout used to calculate.

Without TrainerRoad, you're going to have to decide beforehand how hard you want to ride this interval.  Then you'll need to either do some quick math in your head to figure out, okay, when Sufferfest says go at a 8/10 effort, okay, hmmm, that means 18 mph, and let me see, my excel spreadsheet says 18mph is 220 watts.

Trust me, do yourself a favor, sign up for 1 month of TrainerRoad for $10.  Do the 20 minute FTP test and get your FTP number.  Then do a TrainerRoad/Sufferfest video and see how it all works.

Really, this is triathlon.  $120 for a full year of TrainerRoad.  Most people will spend that on 2 Xlab Gorilla cages for their bike.

I know how you feel, as I did feel exactly as you and put off TR for a year and a half.

Tried multiple methods to simulate TR, including using speed->power charts for my trainer.

Then I finally joined it to try it out, and I've never gone back. Seriously, we're not overselling it. There is nothing out there at puts it all together like TR - it's not just as simple as outputting virtualpower - there are workouts, number logging, social sharing of rides, etc. that all work together extremely well.

Think of it this way - a powermeter costs $1000ish. TR costs almost 10% of that per year, but probably gives even better results than just owning a powermeter. (This is coming from the guy who bought a powermeter 6 months ago and loves it) since the powermeter alone doesn't make you train properly with power automatically, whereas TR does. 

Speed does not easily translate to watts. 

Feel free to try RAD+. The software only runs on a PC. It is currently available for free. Simply register on the web site www.RADplusSports.com and download. There is also an 8 week workout program that was designed by Coach Jorge Martinez.

The Sufferfest workouts have been made available so that the power requirements match (fairly closely) what shows up on the videos.

If you have any questions, feel free to PM me.

There are several trainers that were designed and built such that resistance is a function of speed and speed only. When this happens, it is possible to map trainer speed to power and represent it as Power Curve (PC) or some mathematical function (usually a cubic equation). This notion of virtual power has been with us since at least 2005 with Kinetic trainers, and perhaps much much earlier. RAD+ uses these equations as do other programs to translate speed into watts. If you pick the right trainer, it is straightforward (if not easy).