This article originally appeared on BikeRadar
The democratisation of power meters was kick-started by the headline-grabbing Stages 105 crank in 2013. Before that, all power meters were premium items, but now there are many more affordable options. Truly, Stages gave power to the people.
When it launched, Stages was unique for being a left-side-only crank based meter. This design makes it more affordable, less complex and easier to fit. Power is measured with strain gauges factory-bonded to a left crank, doubled and then sent to a head unit via ANT+ to a computer or Bluetooth to a smartphone app. It's also super-light: this one was just 30g more than a regular Dura-Ace crank.
- Highs: Light, simple, consistent, now tougher
- Lows: Limitations of left-only
- Buy if: You want what's arguably the best introduction to training with power
The limitation of a left-only system is that it can't account for a difference in your left-right power balance and very few people are truly 50-50. What's more, your balance isn't consistent. A bit of muscle tightness in one side will skew your balance slightly, easily creating errors of as much as 6%.
To non-power meter users that may not sound like much but to long-time users a 6% error in a time trial or interval session is a big deal. Add in a real injury and your data will be way out. That said, Team Sky use Stages and have just renewed their deal.
Pairing, waking and pre-ride calibrating is all very easy, and uses an advanced temperature compensation method that prevents drift if your bike lives indoors or the weather warms up a lot after an early morning start.
We got good data that tracked very closely with other meters in simultaneous testing. It caught sprints well, too, which we didn't expect from a lefty.
The original Stages Dura-Ace 7900 meter, which we tested that one extensively against SRM, PowerTap and Vector meters, also delivered reliable data in the same tiny, virtually invisible package. However, that original Dura-Ace crank was susceptible to water getting into the battery area, a situation that would require a new battery at minimum and a (free) replacement crank in the worst-case situation.
Protection has now been beefed up, and having used both we can say it's much more robust. While this Dura-Ace version faces stiffer competition, despite also having dropped significantly in price, the 105 and Ultegra versions are still untouchable as affordable introductions to training with power.