Stages Powermeter Review Part 1

crankpile1Cycling as a sport has undergone many innovations over the years – the derailleur, materials such as aluminium, titanium and carbon fibre, aero bars, suspension, hydraulic braking, and even electronic shifting. When it comes to training and racing however, arguably the biggest change in the modern era of the sport is the powermeter.

Despite being commonplace in the pro peleton, powermeters are still an expensive (and complicated) endeavour with only the most enthusiastic amateurs using them, but there are many benefits to be gained by using a powermeter for training and racing with.

There are quite a few options on the market now, at different price points with different installation points on the bike – with crank based systems, pedal based systems and rear hub based systems being the most prevalent at the moment. American company Stages is the new boy on the scene is by far and away the most simple – and with prices from £599 also the cheapest – of all the current systems available. It is also the powermeter of choice for Team Sky for the 2014 season.

The Stages system is based around the non-drive side crank, and starts life as a stock crank arm from either Shimano, SRAM, FSA or Cannondale. A strain gauge array (as found in other manufacturers’ powermeters) and an accelerometer (the technology that senses you tilt your smart phone and change the screen orientation accordingly) are housed in a small unit weighing 20g that is bonded to the inside of the crank arm. A replaceable battery (type CR2032 – commonly used in calculators) is hidden behind a simple coin twist cover.

As a SRAM user, I opted for the SRAM Rival version. At present, Stages doesn’t work with carbon crank arms (carbon doesn’t provide a consistent deflection curve say Stages), so the company has opted to use the alloy Rival arm for their SRAM version.

As with all of the Stages powermeters, the Stages replaces the existing non-drive side crank arm without changing the bottom bracket or drive side crank. In the case of the SRAM Rival GXP version, you remove the self extracting non-drive side crank arm and then fit the Stages crank arm on in it’s place. The whole process takes about 10 minutes and is easily done at home. The benefit here is that provided your training bike and race bike have the same bottom bracket standard, you can swap from bike to bike relatively quickly.

Garmin Edge 510Stages does not need a proprietary head unit, and instead uses both ANT+ and Bluetooth standards to communicate with 3rd party devices. This further keeps the cost down, as you can use your existing ANT+ computer (provided it has the capability to display and record power that is). As I have the new Garmin Edge 510, I was ready to roll. And that’s it – no magents, no sensors, no extra hardware – just the crank arm and a Garmin and the bike now has the same power measurement system as Team Sky. It’s just a shame I don’t have legs like theirs.

Getting to grips with power
There are those who have been using power for years, and have a vast expanse of knowledge when it comes to measuring and interpreting power. This section is not for you. As someone who has never used power before (other than a WattBike test and a few lab tests on the VeloTron bikes at Northumbria University) I am well and truly a novice. For me, just seeing numbers appearing on the screen was a novelty.

First up, the powermeter needs what is called a “zero reset”. Stages say there is no need to do this before every ride, but there is no harm in doing so. To zero the Stages, you simply set the cranks perpendicular to the floor at use the Garmin head unit to perform the zero reset. It takes a few seconds and then you’re ready to go. Unlike other systems, there is no need to zero the until whilst out on a ride.

Numbers, numbers, numbers
Once pedalling, the power figures begin to display on the Garmin instantly, as does the cadence. If you’re planning on using the Stages on a turbo trainer, you will still need a Garmin speed/cadence sensor on the back, as Stages obviously doesn’t measure speed.

The Garmin Edge 510 offers a range of figures to display, and you can customise your training pages on the Edge accordingly. On my power training page for example, I have average power for 10 seconds, average power for 30 seconds, average power, time elapsed, heart rate, average heart rate and cadence. It might not be worthwhile to everyone having the current power figure on there, as it varies greatly second to second.

In terms of recording the data (we’ll not go into understanding, analysing, or training here – there are plenty of resources available on the Internet and if you are that serious, consider a coach) there are various pieces of software you can use. Garmin’s own Garmin Connect records power data, as does Strava. There are also software options such as Training Peaks (both offline and online) and Golden Cheetah, all of which allow you to download and analyse your data.

To produce a powermeter so cheaply, there have obviously been some sacrifices. The first is the nature of the way Stages measures power. As it has just the one side measuring power, it doubles the power reading from the left leg. This assumes that both legs are pumping out the same wattage, which is a massive assumption. However, the variation between two legs is realistically not that drastic that the power readings aren’t usable, especially if you only have access to one powermeter all the time.

The other criticism is not necessarily down to the Stages unit itself, but is aimed at ANT+ and Garmin. ANT+ powermeters transmit 4 data packets a second, but the Garmin only picks up 1 of these packets. This makes is very difficult to precisely compare one powermeter to another as two Stages side by side would display different data. An SRM for example picks up all the data sent from the powermeter, making it arguably more accurate – but for a massive price difference.

Conclusions so far
Make no mistake, I am not a power expert. This is my first forray into training with power, but Stages appears to be the perfect way for a beginner to get into training with power. It’s cheap (relatively speaking), easy to install, and a lot less fuss that some of the systems out there. I have heard nightmares about battery usage but so far I have not experienced this. I also have no other powermeters to compare figures with, so I cannot report accuracy in comparison with for instance a Quarq. I do roughly know what my power output is from the university tests, and was pleased to see the expected numbers appearing on the Garmin.

As a newcomer, Stages has so far offered an insight into my training and fitness that has otherwise been missing. Time will tell how reliable and consistent the Stages remains, but so far I am impressed.

In the next part of the review, I will be looking into the technology used by Stages, what the long term performance is like, an any issues I might encounter.

Prices start at £599 for a SRAM Rival GXP model / Shimano 105 up to £799 for Dura-Ace models.