In Data We Believe: Stages Power Meter First Look
- by Christopher Jones
- Published: 11 November 2013
The price you pay for data is usually a combination of weight, swapping out your preferred gear on the bike and of course… cash. When the Stages power meter launched in late 2012 there was a lot of excitement; it was priced at $699 USD, weighed under 20 grams, and required simply swapping over your left crank arm for an identical make and model upgraded with the Stages power meter installed.
From the foot of the Rocky Mountains in Boulder, Colorado (USA), Stages Cycling confined the launch of the new power meter to just the US market, but it sparked immediate international interest. Although international purchases were technically not possible, keen cyclists across the globe explored ways to get their hands on one.
Brisbane based distributer FE Sports, who also distribute Garmin (and the competing Garmin Vector power meter) have signed on with Stages and are now working hard to meet demand.
Competitive and elite cyclists pave the way for training and performance improvements. On-Bike recording devices have evolved from the simple cycle computer through to the heart rate monitor and then power meters. Each provide valuable riding information to help cyclists (and their coaches) to train more effectively and to deliver peak performance on race day.
Amateur cyclists and fitness cyclists are rarely fighting for a gold medal or yellow jersey victory, but training to power still provides an opportunity to improve efficiency, strength and effectiveness. Power output is a key indicator of strength, the amount of watts you generate while pedaling. Recording and seeing the power output is valuable both while riding and for post-ride analysis.
Stages Vice president Doug Crawford says, “All indicators are that the power metric, measuring power, utilising power in multiple disciplines is the frontier of where we are at in quantifying work-outs and understanding constants. It’s the new heart rate”
Measuring your power output provides a reference which can be used to track performance over time as well as provide a guide while riding so that you can ride within your functional threshold, maintaining constant power output to avoid bonking (fatigue).
“There’s just so much information pouring in, everybody wants everything. And then they are starting to get to the point where not all of that is useful.” Doug Crawford elaborates, “What we have to do is figure out which pieces are really going to be useful from there and simply from there. You do the big grab and parse it out and focus on what is important”.
While a road cyclist may focus on maintaining a consistent power threshold while riding, a downhill mountain biker in comparison may be more concerned with the pedaling strength out of berms and corners and this power data becomes useful primarily for post-ride evaluation.
Breaking the Bank with Power
Sport cyclists tend to gravitate towards anything that can improve performance such as light weight frames and wheels. Power meters are simply a big investment – even a pro-cyclist may have a single power meter to use between the bikes or may even have to share with other team members.
The power meter market has opened up with a number of new entrants – Pioneer and Garmin Vector are still quite new. To get started you usually have to spend an amount north of $1700. The Cycleops PowerTap hub system provides an alloy wheel version which is, at 899 USD, a lower cost option for cyclists who will accept this alloy rear wheel.
Stages have captured attention by entering the market with a complete power meter solution priced between $799 and $999 (Australian Dollars). This range covers Shimano Road (105, Ultegra and Dura Ace), Track, MTB and BMX as well as SRAM (Rival and X9) and Cannondale Hollowgram SI.
This price point brings power to the people. Although a cyclist riding a Shimano 105 groupset may not be an obvious candidate for a $799 power meter, Stages assured me that yes, there is strong demand for the 105 crank, although Dura-Ace 7900 and 9000 have the highest demand.
Stages Plug and Play
The installation is simple – replace the left crank arm, calibrate and your done. Stages use original Shimano, SRAM and Cannondale crank arms which are modified to fit the stages power meter and in this way offer an advantage over other systems which require cyclists to change from their original or preferred setup and swap out an entire crankset or wheel.
As pedal based systems, the Look Keo Power Pedal and Garmin Vector offer easier installation, although the Look Keo system requires an additional transmitter attached to the frame with cable ties. These pedal based systems provide the benefit of being able to switch between bikes as well as recording left and right side power readings (more on this shortly). The Stages, in comparison, has no extra parts and is the most compact and unobtrusive power meter on the market, letting you use your preferred pedal and cleat system. And it’s cheaper.
Just a left crank, nothing more… really?
Yes – a left crank with a plastic part, the power meter, bonded on the inside. Stages purchases original left crank arms from the Shimano, Sram and Cannondale range and the paint and surface coatings are removed to reveal the aluminium. There is no drilling or milling, the metal is left untouched and the stages power meter is bonded permanently. Strain gauges measure deflection in the metal – these measurements are so sensitive that simply holding a crank by one end and turning it so that it is horizontal records ‘strain’ from the weight of the crank arm itself.
With all of the technology incorporated into the power meter to measure power, cadence and crank position, and to transmit via ANT+ and Low Energy Bluetooth (Bluetooth Smart), the real work, the hard work, is done in the software which ensures that the power meter (which is identical regardless of crank make and model) is calibrated properly for each individual crank and and can record an accurate power reading.
Is Left and Right an Issue?
Most other power meters provide a left and right leg power reading whereas the Stages multiplies the left leg power reading by two, which means that this is the biggest criticism that Stages endures.
Most cyclists don’t have have a perfect 50 : 50 balance of power and while riding this balance can also change, for example whilst cruising compared with sprinting or riding while fresh and fatigued. Stages state their solution provides a ‘real power number’ that 90% of riders will be able to train to and the ability to constantly analyse the left and right side balance of power is comparatively insignificant. They maintain that inconsistencies in power balance can be tackled through biomechanics and a bike fitting, and potentially can be neurological.
In practical terms, the left side only power measurements means that the Stages power meter is simpler and more affordable than other power meters. For the majority of cyclists who fit within the norms, the overall power output will be the dominant metric for training and analysis.
Accuracy of Stages
As with left : right power balance, the accuracy of this newcomer has also been questioned. If a Quarq or SRM power meter costs two, three or four times the price, does this make Stages inferior on price alone? While each system has its pros and cons, independent testing shows that Stages certainly can play with the big boys.
Accurate testing is extremely painstaking and Ray, from the popular DC Rainmaker blog, has done much of the hard work in comparing Stages with up to three other power meters. If you have a spare two weeks then you may have enough time to read the entire extremely detailed reviews of the Stages Power Meter (Part 1 & Part 2)
The refreshingly short one sentence summary: DC Rainmaker didn’t see any relevant inconsistency in the left-side only readings for himself, and the accuracy of the Stages was comparable with other power meters including Quarq and PowerTap.
In creating this power meter, the engineers have included a few features to ensure that the Stages is innovative and not just a “me-too” product. On top of the compact and lightweight format, which are significant differences to the competition, this power meter automatically compensates for temperature changes. If you start your ride and it begins to get hotter or colder then this affects the calibration of the strain gauges. In the comprehensive tests from DC Rainmaker (mentioned above) temperature changes sent the Quarq Power Meter over 50 watts out of sync while the PowerTap also started to drift. Stopping and calibrating these two then returned the power readings inline with the Stages which were being automatically corrected as the temperature changed.
Stages also is able to transmit torque 64 times a second using the new low energy bluetooth. As the Senior Vice President of Stages, Pat Warner, explains: “If you’re doing a two hour ride it’s not important, but if you’re on a trainer and want to evaluate your pedal stroke you can see the differential in your downstroke and upstroke and if you’re pulling through”
Most head units can’t read at this speed, however the next update of the Stages App will allow this data to be captured. A limitation is that an iPhone 4S or newer (or iPad) is required as they have the compatible bluetooth 4.0 technology. For everyday riding the current capability of ANT+ and head units such as Garmin are more than sufficient.
In Data We Trust
Power is all about the data; the data for post-ride analysis and the data that is interpreted live to provide useful information while cycling. During my test ride with Stages, even steady riding delivered varied readings on the display – I had the Garmin set up to show live power meter reading plus a 10 second and a 30 second average. Stages see themselves as a facilitator; they have built a tool to which other services and systems can connect. To better understand power and to train to power, Stages have a partnership with Training Peaks Software and provide a 1 month subscription with the purchase of a power meter.
More services will inevitably appear over time that will be synchronised to your training plans and cycling history to let you stay ‘in the zone’ instead of trying to compute the various metrics.
Pat Warner provides a glimpse into the new reality that power can offer “You can start seeing what kind of aerodynamic differences you are going to have from wheel to wheel or from skin suit to skin suit. It’s been an interesting progression from ‘Power was only for your body’, now you can start to make equipment selection.”
An Overwhelming Demand
At Bicycles Network Australia we are looking forward to testing Stages and, as the production facilities in Boulder, Colorado ramp up to meet demand, this will require a little patience. In the meantime, the distributor FE Sports is fielding dealer and customer inquiries, so get in touch.
RRP Pricing Guide (Australian Dollars)
$999 Shimano Dura Ace (9000, 7900, Track), Shimano XTR (M980, M985)
$899 Shimano Ultegra (6700, 6800), Shimano XT, Cannondale (Si HG)
$799 Shimano 105, SRAM Rival, SRAM X9 GXP
(different crank lengths for all models are available)