Use a power Tap or disk wheel

What is the best choice?
Use a Power Tap laced to a Zipp 808 or have no power meter and use a Zipp disk wheel and a heart rate monitor??

I assume you mean for a TT. I think this would depend on the course, but I would personally probably take the PM and the less aero wheel because I think that good power management wins out over aero wheels on a complex course (i.e., variable grade). I am facing this precise decision for next spring, but my decision is slightly more complex due to a special piece of VP pacing technology I am working on. Although, for some reason I am looking primarily at the Zipp 404s. I can't remember why. Maybe I should take a closer look at the 808s.

How about CH-Aero Wheel cover with Power Tap wheel?

That'd be a good combo. I think one of the members of this forum uses that combo -- maybe Woofer? Bear in mind that the wheel covers will be technically illegal next year when USCF goes to UCI rules.

Yes, the original post was referring for use in time trials. I thought about the disk cover but your right they won't comply with the rules. So it still stands, can more time be saved by pacing with a PM or does a disk wheel and heartrate win?? Unfortunately the courses that I race on change, so the question remains I guess a bit.

This is really good question. I have been using my PT rear wheel and a tri front for all the TTs around here and intended to go with full aero setup for the final district TT.

However, I have found the PT data (and cyclingpeaks) to be so valuable when riding and after riding that I intend to just ride the PT rear.

It would be different if I had a TT on a straight flat course (no power variations) or had a chance at winning where every second counted, but since neither of those things are going to happen, I am just sticking with the PT.

Of course the real solution is to buy an SRM , but they are way too expensive.

It works fine, just have to put it on a few days beforehand and not leave it til the last second. The 2004 rule book said the rules were changing in 2007. They changed the rule in 2005 so now only riders participating in USCF events to qualify for UCI events have to abide by UCI bike technical rules or riders attempting to set a national record. The 2005 rulebook supercedes the 2004 rulebook but maybe they could change their mind again in 2006. But it sounds like they only want P12 men and women to worry about it.

It's seems that I'm not alone with this question. I surprised that none of the coaches that really love the power meter devices have an opinion. I'm thinking that to train with a Power Tap is good but to really do your best time I think one should invest in a SRM or forget the PT and go with a Disk wheel.

I think the problem you may be encountering is that not many people are experts at pacing with power and there is a paucity of data on the time advantage of pacing with power. The benefits of a more aero wheel are much more easily computed. The benefits of pacing with power first requires an assumption about the pacing strategy to be deployed. Then, it requires testing the deployment of the pacing strategy with and without a PM. Furthermore, the time advantage of pacing with and without a PM will vary from cyclist to cyclist -- some of us are just better at pacing with RPE, speed and HRM than others. Some pacing strategies such as a constant power strategy would be infinitely easier to deploy than, say, a highly variable power pacing strategy. I know where I am going -- highly variable power pacing. I simply plan to systematically identify and attack the impediments to deployment of such pacing strategies.

I believe that Ric has commented before that even elite riders that he has worked with were terrible at pacing for TT's - typically starting at a pace that was *much* higher than that capable of being sustained for the entire ride, which results in a sagging power in the middle of the ride before an all-out push at the end.

I remember that Rapdaddyo once experimented with covering his PM and trying to ride at a particular power level, and he wasn't too successful at the time. When I did my TT (with PM) I still started out much faster than I wanted to. Even after looking down and seeing that I needed to back off, when I looked down again 30sec later I found that I still hadn't come down to where I needed to. I just felt so good at the beginning that I wanted to go hard.

In reality, the choice (PT or disc) depends a lot on the rider and how good they are at pacing. The funny thing is that even people who consider themselves good at pacing often discover differently when their effort is recorded on a PM.

I totally agree, as I did a 15km TT yesterday. At the beginning of the TT I looked down and was amazed at the read out and like you it took me awhile before the power started to come down. So would I have had a better elapsed time had I reduced the power output at the beginning? I'm thinking this would be more advantageous when I do a 40km TT.

For a perfectly flat, windless course, a constant power effort at the max sustainable power will produce the best time. So it's best not to start too fast and a PM will help.

For a real course, acheiving the best time is a result of producing somewhat more power during the 'slower' sections of the course (ie, uphill or upwind) and somewhat less power during 'faster' sections of the course so that the overall normalized average for the ride is equal to the max sustainable power for that race duration. Sometimes you may want to start fast out of the gate, but other times you may really screw yourself by going hard just because you feel good at the start. An example would be a course where the wind is at your back on the way out and in your face on the way back.

Ok, I have a 40km TT coming up next weekend. The coarse is relatively flat and an out and back coarse. So for example my threshold power ( a power that I can hold for an hour) is 250 watts. Now like you said if the wind is at my back, I should pace at 140watts on the way out and 260 watts on the way back. Would that produce an optimal time?
The previous week I did a practice TT on the same coarse without a PM and did it solely on heart rate. I managed to do it in 58 minutes. Keep in mind this was the first TT I've done in years and I haven't done any racing this year at all. So I suspect anything I can learn to pace myself will help. Thx for any advice as I want to beat 58 minutes next week. Oh ya is there anyway of predicting my time in advance??

Ok, I have a 40km TT coming up next weekend. The coarse is relatively flat and an out and back coarse. So for example my threshold power ( a power that I can hold for an hour) is 250 watts. Now like you said if the wind is at my back, I should pace at 140watts on the way out and 260 watts on the way back. Would that produce an optimal time?
The previous week I did a practice TT on the same coarse without a PM and did it solely on heart rate. I managed to do it in 58 minutes. Keep in mind this was the first TT I've done in years and I haven't done any racing this year at all. So I suspect anything I can learn to pace myself will help. Thx for any advice as I want to beat 58 minutes next week. Oh ya is there anyway of predicting my time in advance?? I weigh 158lbs and stand 5'10" tall and no fat in the mid section, I'm thinking this discription may help.

I personally have gotten so used to pacing with the PT that I don't think I could pace without it. I mean, I could, but why chance it?