Training with power

I like numbers! A power meter was inevitable, it was just a matter of when. When the price was right, and when I had completed my research. As my other half will attest, I don’t make impulsive purchases, in fact it can take literally years before I commit to spending, and the more it costs the longer it takes.

I had been scouring the internet for about two years, discounting a number of options due to reports of inaccuracies or unreliability. For example, the Stages left hand crank based PM, popularised by the Sky team, was reasonably priced but it’s only one sided (therefore not that accurate) and suffers many reports of unreliability. The problem with one sided PMs is that the left/right balance can vary with total output. To get total power they simply double the power reading from one side. If the left leg is supplying 49% of the total power then the PM will under report the total power by 2%. This in itself is not too much of an issue as long as the imbalance remains constant, but if for example, at a higher degree of effort the left and right legs become more even, supplying 50% each then you no longer have consistently in your readings.

So I was after a PM that measured total power, was reliable, accurate, and reasonably priced. So when I saw a Powertap GS hub at a bargain price of £300 I was all over it like a rash. That was less than half the advertised price at a popular online retailer (or anywhere else come to that). Even better, when it arrived, it came with the dual cap, i.e. it sends out not only ANT+ but also Bluetooth signals, according to the manufacturers website this was listed as an ~£50 upgrade. RESULT!

Eventually my rim and spokes arrived from Germany (actually this took less than a week) and a wheel was built.

So, after about 20 rides and 30+ hours, what are my conclusions?
1. Generating all this extra data is fun, or rather the post ride analysis gains an extra dimension.
2. For most types of training, using heart rate is more effective.
3. For short intervals a PM is definitely more useful than a HRM but I do those on a turbo trainer anyway.
4. The PM is very motivating for sprint training, making you dig deeper to hit the numbers every effort, and telling you when your effort falls below the level that tells you it’s time to go home.

I’ve not tried it in a race yet but my plan was to rebuild it into a race wheel for next season. I suspect that for TTs it may give a little extra help for pacing. Mind you at £300 I am so tempted to buy another one and have both a training wheel and a race wheel with power.

Postscript: Power meters were not around until after I had stopped riding and coaching in the early ’90s so I had to do a fair bit of reading to catch up. There is so much information on the internet now though that by the time I bought the much quoted tome ”Racing and Training with Power” by Hunter and Allen there was almost nothing in it I didn’t already know, however this book is a good place to start if you know nothing about power meters.