How would you recommend calibrating the CT's RR prior to starting an ErgVideo ride? I'm used to starting a 3D ride and then doing a few quick pause/calibrations throughout the first 5-15 minutes of the ride until the RR number stabilizes. Then I continue on with the rest of the ride until I'm done. Is there any analogous procedure I should follow? Should I just do 10-15 minutes in MR (or even 3D?) w/o any video started to get to a stable RR first...then fire up the video and assume the same RR is maintained?
LOTS of people cut corners in the roll-down calibration of their CompuTrainer. If you want the benefits of power training, and to really "get" the ErgVideo thing, calibrate you computrainer and set the rr factor correctly. I'm not giving anything new here, it's all in your CT manual, but some people want more detail. Here is what works, step by step, and WHY. I get excellent agreement between SRM's and PowerTaps when I do it right.
I answered:
I actually recommend you do the calibration before starting the ergvideo ride. I'll explain why in a minute. I know it is boring, but necessary. Do a spin down and get the initial "cold" number (aim for around 3-3.3 ish when it is cold). Now, it is VERY important to go into erg mode for the next step. F3 to accept the spin down, F2 to go to erg mode. Now set the power to something like 150-200, whatever is a reasonable initial warmup pace for you. Now ride for about 5 minutes, go to cal mode with "+-" together, and do another spin down. The number will have changed substantially, and use F3 to accept and then F2 to move to erg mode. Use this time to warm yourself up, too, so going to progressively higher power is a good thing.
I suppose you can do a short 3d-ride with some hills, with pause-calibration as described above by the customer, and then turn off 3d, and move over to ErgVideo. Just be sure the warmup is real, and vigourous enough to warm that tire.
The reason you must go into some "powered" mode is that the tire does not heat much in Cal mode. SOME people stay in cal mode, indicated by the speed showing and "up" or LL" or "cc" showing. It is a useless warm-up state. In this state, the CT magnets are off and your tire does not heat much, and not nearly to the temperature that it will heat to when you are really riding. So you will be miscalibrated, on the COLD side. When cold calibrated, the CompuTrainer OVERESTIMATES power due to rolling resistance, and thus will not drive the magnets as powerfully as it should, when it should, to hit a target.
I recommend you keep riding and check the cal number at 10 minutes. Then repeat every minute or so. Eventually the number stabilizes and you can accept the number and then start the ErgVideo. I do recommend a number like 2-2.5 for ergvideo. The reason is not related to accuracy so much as an ability to track at low loads, so you can feel even small variations at low power settings. The reason for 2-2.5 is that it minimizes power due to rolling resistance, without slipping, and this enables the CT to track you to correct power at lower power load settings. Think of it this way, if you are confused...it makes it feel more like "no resistance" when the load=0. A tighter roller will be harder to push (since the magnets are 'off at 0-load), so with a tight roller you will push 130W to go at 12km/h when a looser roller may only require 100W at same speed. If you are still confused, read my article in the other part of the FAQ about Erg mode vs 3d mode for more on the low-power tracking issue.
I have three good reasons for using this method, and I can probably come up with more if I take too long to type this:
1)There is no "pause and calibrate" function in Coaching CS or Multirider. In Multirider, I used to just unplug the connection, do a calibrate, and then plug-in. During this time, indeed MR3-erg mode will continue merrily along and MOST of the time, reconnecting is never an issue, and you remain synch'd. One time in ten however, and I'm suspicious it is more often with Vista and the Sewell USB drivers, the MR3 will become unsynched. It isn't ergvideo, you can do this with MR alone. You can become 10-17 seconds BEHIND the power curve.
So I don't do this anymore. You can try it, but I don't cry to me if you see it not work from time to time. I'll just say "Yeah I know, and it's got nothin' to do with ErgVideo. You are also using the CT in a way that isn't recommended nor supported, so don't expect it to work." So no sympathy from this corner. Don't unplug during an ergvideo ride either. You'll get same reaction from me: "don't do it".
2) YOU NEED A GOOD WARM-UP YOURSELF before riding a race video. People do not believe they will get a race-level workout. They do not understand that they are FORCED to perform. If you ride a race video at your true threshold, you will get a race effort. People warm-up for races a lot longer and a lot harder than some 10 minutes at 0 resistance.
3) It works.
You could indeed run an erg file in MR3 or CS erg mode, as a specific warm-up. That is a good idea in fact, but be sure to calibrate and seriously warm-up your machine at real power before running the ErgVideo ride. You can do your warmup in an uncal'd state, you will get to know the resistance, and here again, the adjustable threshold in MR3 is handy.
Read my long article on erg mode vs 3d mode in the FAQ.
Hope it helps.