blog entries

I've got the power (but do I need it?)

Power meters. Who needs them? I am aware of the rational arguments about a watt being a watt, whatever the weather. But what’s in it for the Black Sheep cyclist or indeed any non-pro for whom £1200 or more represents a significant investment?

I’m now into my third month of ownership of the Rotor Power cranks and I think I’m qualified to answer the question.

First, I have to admit that I don’t need a power meter. Just like I don’t need electronic shifting or a carbon frame. Or more than one bike. Or gears. Or rain-wear. You can take minimalism too far, you know.

So just because a power meter is the latest thing, and therefore the most recent thing I was perfectly happy without, it doesn’t mean it’s superfluous to requirements.

So my first challenge when taking delivery was which bike to put it on. I went with the bike on which I spend most time, do most kilometres, do most training. My winter training bike got the nod and also some nice new Rotor Q-Rings to go with the cranks, set up the same way as on my race bike. 

The argument against what I did is that it is that you only produce maximum watts in the heat of competition, so I will never have a true idea of my maximum output unless I use the power meter on my race bike. My argument is that I’m not spending £1250 on something that sits idle in the shed for nine months of the year. And anyway, there's plenty of competition on our group rides, thank you very much (Tim will concur).

I spent the first two weeks with the Rotor on my rollers, just trying to equate my previous preferred method of output – heart rate – with the wattages popping up on my Garmin. During this time I followed Jesper Bondo Medhus' excellent 14-day VO2 max improvement programme, just to give my learning some structure and to reap some health benefits besides. Then I took to the Cotswold roads to apply what I’d learned to the real world and I’m pleased to report four principle outcomes:

  • I learned what my strengths and weaknesses are as a cyclist. This is critical information and was not what I expected. This process involves cycling enough kilometres over varied terrain to generate sufficient data to determine my maximum outputs over a selection of time periods: 5sec, 60sec, 5min and 60min (this last is also my FTP or Functional Threshold Power, the basis from which to design future training programmes). Setting my readings against the ‘industry standard’ power profile chart which you can find on Training Peaks or in any number of books on the subject, I learned that I’m strongest over 5min and weakest over 60sec. I also learned that ‘strongest’ is a relative term… I was pushing out wattages defined sadly as ‘moderate (eg. cat 4)’ in the power profile chart. I have a long way to go…
  • Knowing the above, I have planned a few training sessions that will raise my peak power over 5sec and 60sec (my lowest readings) and I look forward to seeing them rise. They need to; there is the sprint for the town sign at the end of every ride to consider.
  • I learned how much power I can produce in any given situation remarkably quickly. I can drive a road now and know how many watts it’d take to propel me up it on a bicycle. This is useful because, knowing my strengths and weaknesses (and wanting to work on my weaknesses) I can plan routes and training sessions very easily.
  • Lastly, I’ve been able to clean up my bike, removing the magnets and sensors that measure cadence, because it’s all taken care of by Rotor Power now. As an aesthete as well as an athlete, this is a big deal.

In the interests of balanced reporting, there are two minor niggles too. Actually one is quite a major one.

Minor niggle first: now that I’ve removed the rear wheel magnet and speed/cadence sensor, I have no way of measuring speed on the rollers. This really is a minor issue though: all my roller sessions are now based on wattage and time.

The bigger issue is that occasionally the software in the Rotor Power needs updating. One does this by downloading the update to a PC and transmitting it to the power meter via a ANT+ dongle. My niggle is not that I have to purchase a ANT+ dongle (though it would have been nice to have had this included in the £1250 initially). My niggle is that I don’t have, nor am ever likely to have, a PC. Which means I have to schlep the bike to the shop every time I need an upgrade.

Apart from that the Rotor Power is a wonderful piece of kit which has transformed – in a very short space of time – the way I measure progress on a bicycle. As long as I put the training in, I anticipate my best season yet in 2014 because I am able to identify what work needs to be done and can measure it accurately.

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