Power meters (and a bit of Strava data)

[sploo]

Having started riding again a bit more regularly (and now with all this new-fangled technology such as bike computers and Strava) it's been pleasing to see evidence of positive progress over the last few months. I've just started Strava's free trial for their subscription service and the Effort Comparison feature is a great way to see progression on segments over multiple rides.

What I don't have at the moment though is a power meter. Obviously if there's a strong headwind on a day you're riding then you could end up going slower and have a higher heart rate (evidence when taken together that might indicate reduced fitness). However, I assume that a power meter should allow a more accurate assessment of fitness over time (when combined with speed and heart rate data).

The Magene PES P505 seems to be well reviewed for a budget power meter. Anyone using one, or got experience with power meters and monitoring fitness over time (good/bad/worth it/not worth it)?

 

[Dogtrousers]

I treated myself to a PM at the end of Covid during which time I spent an unreasonable amount of time on the turbo and got used to thinking in terms of power.

The are mainly useful as a training tool, enabling you to train in specific power zones. Although I do all of my power zones based training on the turbo (no PM needed)

They are also helpful (I find) on longer rides when you want to keep effort levels down during those first few hours when everything feels easy. Also, as fatigue sets in, your power output drops and if you know your body this gives you a "sort of" quantitative fatigue feedback.

If you do FTP tests then this is a good way of monitoring your fitness, however this is much, much easier on a turbo than on a bike outside.

But does everything have to be useful?. PM data is also just interesting in its own right. Do you ever glance down at your GPS to see your speed? Well power data is like that. In fact on my most used GPS screen I don't show speed any more.

Also it's interesting for reviewing a long ride. I can look at my power figures for a long ride and see where my endurance started to run out and my body went into "battery saver" mode. This is a bit like looking at ride photos as it's a snapshot of how I was feeling physically. I don't use Strava but I imagine they could do some interesting data visualisation stuff with power data.

So if you are inclined towards recording data they can be an interesting and useful luxury. Especially if you do power zone based training. But they are undeniably expensive.

Worth it? That's for you to decide.

 

[sploo]

I have a Wahoo KICKR (which monitors power), but I've only got it recently so I've mostly been riding the bike rather than the indoor trainer. I haven't yet done an FTP test on it (too wuss to take the pain just yet).

I suppose I should spend some time on the KICKR to see how useful power data is in Strava.

 

[Dogtrousers]

. I haven't yet done an FTP test on it (too wuss to take the pain just yet).

I prefer a ramp test is to a traditional TT type test. Partly because it's less horrible to do, but also because it's less dependent on mental attitude and motivation on the day.

 

[sploo]

Update: I've ordered a Magene PES P505.

I don't think any actual power numbers are particularly important/meaningful to me, but I've found that "data" seems to be very motivating in getting me out to ride. E.g. am I getting quicker along a particular Strava segment without an increase in average heart rate. I guess having actual power figures will be a truer indicator of fitness (rather than time; as weather conditions could affect times).

I've also found it quite interesting to ride to a set power level (ERG mode) on the KICKR, as it adds a bit of variety rather than just plodding away at some particular speed/cadence.

 

[BSRU]

For me a power meter was a great investment, I can directly compare segments today with the same segments from 10 years ago.
Lets me know that even though I'm alot older I can still put out the same power .
Speed/time is too affected by headwinds and heart rate varies too much depending on how well I am.

 

[sploo]

Update: installing the Magene PES P505 on the bike was relatively simple. I had some issues getting their app to register (in order to calibrate the sensor), but it eventually worked.

The product itself seems good. They're about 100g heavier than the 105 (non-Di2) parts I removed, but I've noticed no issues in use.

Main takeaways are that Strava's estimates of wattage (from before I had the power meter) are pretty good vs the numbers from a real power meter. The calorie count computed by my Wahoo app however was miles off; about twice the figures now calculated from real power data.

I've mostly been riding to my heart rate (trying to stay within what is likely to be Zone 2 riding) but I'm starting to understand the effect of power (i.e. being able to pre-emptively keep the power level down in order to prevent the heart rate from rising - as power is obviously something that can be reacted to much more quickly).