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Training with Power/Watt Meter, SRM or PowerTap Hub(6 posts)

Training with Power/Watt Meter, SRM or PowerTap HubMalc
Jan 6, 2002 9:07 AM
I have some Questions about Power Training:

What Cat riders generally use power training? Cat5 - Pro?

Reliability issues, like training in Northern climate in Jan-Mar?

Has it made a difference in your training vs. heart rate alone?

Is it worth the investment?

What are people general opinions on products that are available in the marketplace for measuring cyclists power?

I am thinking about getting a power measurement device, I am a Cat4 racer that would like to upgrade to Cat3 in the next year, is it worth it or is it overkill for my skill level?

Thanks in advance for your opinions
re: Training with Power/Watt Meter, SRM or PowerTap Hublitespeedcat
Jan 6, 2002 1:48 PM
I am interested in the same thing, but I am not paying $700 or more for it. I just bought a Ciclomasted CM 414 alti M computer and it gives a virtual watt based on your weight(bike and rider) it is within +/- 6% of the tune power tap. Only draw back is that you have to update your weight if you drop as the season goes on. They have two versions: one is $139 an d the other is $199. The only difference is that the $199 will download to your computer. Check them out at or
re: Training with Power/Watt Meter, SRM or PowerTap HubDuane Gran
Jan 7, 2002 6:26 AM
I recoomend you check out the wattage mailing list:

It is a rather technical discussion group on the topic of training with power. There are many good insights and occassionaly you get some inside info from Polar and SRM employees. To answer some of your questions:

1) Power training is beneficial at any level of experience provided that you actually use the data to improve rather than entertain yourself.

2) Is it worth the investment? I'm sure people asked this sort of question about the HRM 10 years ago. I personally think power training will be the next big thing among serious athletes. I think it is worth it in order to have an edge over much of the competition who trains by HR primarily.

3) Opinions on products:

* SRM - This is the gold standard of power measurement, but it is the most costly. Everyone would have this if money were no issue. It is nice that you can use any wheel on the bike and still measure power, however if you have multiple bikes it is a pain to move the crank between them.

* Powertap - There have been reliability issues in the past, but more and more people are reporting trouble free use of them. The price is more reasonable, in the neighborhood of $800. I recommend avoiding a second hand unit to avoid older production lines. The accuracy is good, but since it is integrated into the hub it means you can only measure power with one wheel. This rules out disc wheels and a variety of other wheelsets. On the plus side, it is quite easy to put the wheel on another bike and measure power.

* Polar - This unit is shipping "very soon" in the united states and early reports show its accuracy to be quite good. The price is $350 and it works with the Polar S-710 HRM ($275), so in all it is a little cheaper than the Powertap. The polar unit is easy to setup for multiple bikes (with the purchase of a few extra pin sensors & such) and you can use any wheel. The only real downside is that Polar uses a 5 second recording whereas SRM is variable (.1 second at best) and Powertap uses 2.5 seconds. This means that the unit is less than ideal for recording sprint and max power efforts, given the fairly wide window of data points.

There are some other systems, but these are the three I'm most familiar with. I'm personally inclined to the Polar unit. Each of these systems comes with software for the PC to analyze the data. I've used the Polar software and like it very much.

I'm also a cat4 with similar ambitions, so I don't think you are out of line to want this advantage.
Power is all that matters...Kyle
Jan 7, 2002 9:28 AM
Other training data just dances around what you really care about--how hard you can turn the cranks and for how long. I am convinced that at some point, HR monitors for cyclists will go the way of toe clips in favor of power measuring devices.

I've been using a Computrainer since '98 (or thereabouts) and don't know what I'd do without it. Why?

Primarily because it allows for an objective measure of training strategy. I periodically race a ten mile time trial course against my personal best from the same date the prior year to guage my (hopefully) improvement. This fall I also did my first max power test and have started a lifting program to improve it. In the spring I'll know exactly how much lifting did or didn't help me and whether I should do it next winter or if it was a waste of time.

I also like the Computrainer's ability to maintain a constant power output during a training session (ie cadence variations do not affect difficulty) giving you a consistent workout that isn't skewed by cardiac drift.

Another interesting feature is the ability to do intervals at your goal power output. For instance, lets say you want to average 300 watts in your year end TT test, but you're at 280 now. Do your intervals at 300 and slowly increase the duration (I adapted this workout from an olympic swim team strategy.)

Finally, the video game quality of these trainers can be kind of entertaining--particularly (apparently) if you get the Netathalon upgrade, which allows you to enter Internet races.

Of course, the drawback to a trainer based system is that you can't use it on the road where you spend most of your time. In my experience, though, perceived effort and HR work pretty well for gauging your outdoor workouts.

I wouldn't recommend the Computrainer as it is very expensive and kind of glitchy. The Performance Axiom trainer is on sale (refurbished) for $299 right now, which seems like a reasonable deal.

Good luck.
Cateye Cyclosimulator - has watts. Any good?ChrisA
Jan 7, 2002 12:00 PM
My Cateye Cyclosimulator 1000 displays watts. Is this accurate? You can not input your weight, but I'm not sure that would matter, except for calculating watts per kilo. I primarily use my rollers indoors, but am thinking about doing testing on the Cateye.
Cateye Cyclosimulator - has watts. Any good?Kyle
Jan 7, 2002 12:36 PM
Never seen any info on this system, so I can't really say.

The important thing is that the system is consistent, not necessarily accurate--you need to be able to guage changes in average power output and not so much exact absolute numbers. For instance, I am using the original software that came with my Computrainer because I'm concerned that upgrading will create an inconsistency in my testing data (though it would probably have improved absolute accuracy.)

Body weight is only important in systems that estimate power output through a mathmatical calculation using variables like grade, wind & rolling resistance, speed, etc.