Should you buy a power meter? After all, they aren’t cheap and the sport of triathlon is already expensive. You’ve spent a small fortune on bicycles and all of their assorted and costly components. And don’t forget the entry fees, travel to races, special foods and nutrition, and on, and on, and on.
So why should you get a power meter? The short answer is that you simply are more likely to achieve your race goals by training—and racing—with a power meter than without. It is the most affective tool you can get to go faster on a bike. Here are some things to look for when you're looking for a power meter, from DCRainmaker.com.
Power Meter Placement
There are four main areas that we see power meters placed today:
Features and Functionality
Now that we’ve covered where each unit goes, let’s talk about the features that the power meters on the market have today:
Total Power (Watts):
This is the obvious one – every power meter has this today (even fake ones!). This is simply measuring and transmitting your total power output to a head unit of some type.
Another relatively obvious one, every power meter on the market today except the Polar/Look solution has this. This allows you to use one of dozens of different head units out there.
Bluetooth Smart (or BLE/BTLE for short) is the relative newcomer in the market. As it stands today, the only unit offering this is the Stages power meter – which offers dual ANT+/BLE. PowerTap has recently announced they plan to offer interchangeable caps for it as well. And while not quite as ideal as dual, the interchangeable caps makes a lot of sense going forward.
Estimated Left/Right Power:
This became all the rage over the last 18 months or so, starting with the SRAM/Quarq RED unit offering left/right power. That platform works by essentially splitting your crank in half and assuming that any power recorded while pulling up is actually coming from the left side, whereas pushing down is from the right side. Thus, an estimation. It’s good, but not perfect.
Actual or True Left/Right Power:
This is limited to units that can measure your power in more than one location. Thus why we see it on pedals, as well as the more expensive crank-arm based power meters. You can’t measure it directly at the spider, instead you have to measure it upstream of that.
Pedal Smoothness & Torque Efficiency:
These two metrics are just making it into the high-end power meters which contain true left/right power measurement. Today that’s only the Rotor and Pioneer units, but Garmin has stated they’ll be adding it down the line via firmware update.
All but one unit on the market today (SRM) supports battery swapping by yourself. SRM requires you to send it in. The remainder of the units out there today utilize a CR2032 and similar coin-cell batteries. Most get between 200 and 400 hours of run-time before you simply replace the battery.
All units on the market today support some sort of calibration function, though to what extent is what differs. Some have numerous options (i.e. Quarq with an app allowing you much further access), while others are more black-box (i.e. Stages and Polar). For the most part, your primary concern here is really that some sort of calibration occurs, and that you can trigger it to happen on demand.
For more in-depth research and comparison on the different power meters on the market today read the blog post by DCRainmaker: http://bit.ly/1jXoull