Photography by Matt Wikstrom

Quarq ELSA RS power meter review

by Matt Wikstrom - November 7, 2014

Quarq has been refining its crank-based power meters since 2006. The company's latest road crank, ELSA RS, features a four-bolt spider specifically designed for Shimano chainrings. In this review, CTech Editor Matt Wikstrom takes a closer look at what the ELSA RS has to offer.

Quarq was founded by Jim and Mieke Meyer in 2006. At the time, the couple were living in Australia, and in between triathlon training sessions Jim started working on a crank-based power meter design that would be more affordable than SRM’s system. He also wanted a system where the battery could be replaced in the field.

Quarq unveiled its first power meter at Interbike in 2007. From the outset, Quarq used strain gauges in the crank’s spider to measure torque and the original CinQo was designed to suit a variety of cranks. Aside from easy battery replacement, the CinQo was distinguished by its early use of ANT+ for wireless transmission of power data.

SRAM acquired Quarq in 2011 with Jim appointed as Technology Director. The company continues to operate in Jim’s hometown of Spearfish, South Dakota where all manufacturing and development are carried out.

Quarq’s range of crank-based power meters currently comprises four models for the road and one for off-road use. The major difference between each model is the design of the spider, which varies to suit different chainring sizes and patterns. The ELSA RS crankset is the company’s latest offering, which utilises a spider with a four-bolt pattern to suit Shimano 11-speed chainrings, and for the first time, incorporates active temperature compensation to further improve the accuracy of the power meter.

What’s in the Box and What’s Not

The ELSA RS is supplied as a crankset with a pre-installed battery, a selection of magnets, a pair of washers for the pedals, and a quick-start guide. There is a choice of three lengths (170, 172.5, or 175mm) and two axle types (SRAM’s GXP or BB30) with a recommended retail of $1,900 (GXP) or $1,950 (BB30). However, buyers will have to supply suitable chainrings, a compatible bottom bracket, and an ANT+ device before they can start measuring their power output on the bike.

The ELSA RS crankset is designed for Shimano’s 11-speed four-bolt Hollowglide chainrings. The four-bolt pattern allows compact (34/50T), mid-compact (36/52T), and standard (39/53T) chainrings to be interchanged, making for greater flexibility than the five-bolt patterns used by Quark’s other road cranksets, though the chainrings are expensive (at least $200/pair).

For those buyers swapping out cranks with either with a GXP or BB30 axle, no more hardware will be needed and installation will simply be a matter of sliding the right crank and axle into the bearings (and spacers/wave washers) and attaching the left crank arm. For those using a different axle (e.g. Shimano’s 24mm axle), a suitable bottom bracket will have to be obtained and installed, adding at least $50 to the purchase price. It is worth noting that the ELSA RS is not compatible with some bottom bracket standards such as BB386.

Quarq does not supply a head unit with the ELSA RS but recommends Garmin Edge 500, 510, 800 or 810 devices. Any other ANT+ enabled device (including an iPhone with an ANT+ adaptor) can be used to view and record power data from the cranks. For those buyers that don’t have a compatible device, they will have to spend at least another $100 to get started.

When added together, the extra costs make for a total upwards of $2,250. When CyclingTips founder Wade Wallace first reviewed Quarq’s CinQo Saturn power meter in 2011, the local retail price was $2,300 sans ANT+ device, so little has changed in Quarq’s pricing even as the company has updated and improved upon its power meter technology.

Details on the Hardware

Five strain gauges are positioned in the spider of the ELSA RS to measure torque. By comparing measurements for the downstroke and the upstroke, the system can also report the balance of power between the right and left legs without directly measuring the output of each leg. In doing so, some assumptions are made, and the system cannot report power measurements for each leg like the systems from Pioneer and Garmin.

Cadence is crucial for the calculation of power by crank-based power meters. The magnets that are supplied with the ELSA RS crankset are designed for the cadence sensor in the spider, which comprises a series of reed switches.

Interestingly, Quarq also installs an accelerometer in the cranks for measuring cadence. It’s a curious redundancy, however excess vibrations (think cobbles) will interfere with the accelerometer, so Quarq recommends installing a magnet and using the reed switches for the greatest accuracy. Under these conditions, Quarq claims the accuracy of the ELSA RS is ±1.5%.

The strain gauges employed by the ELSA RS are very sensitive and susceptible to changes in temperature. In the past, Quarq has relied on passive temperature compensation based on the predicted (rather than known) effects of temperature on the power meter. In developing an active temperature compensation system for the ELSA RS, Quarq directly measured the effect of temperature on the power meter by collecting over 10,000 data points for temperatures from 0-130°F (-17 to 54°C).

It makes for very sophisticated calibration of the power meter that the system refers to as it measures the temperature for each pedal stroke. As a result, Quarq claims the ELSA RS boasts the most accurate and precise power meter it has ever manufactured.

The ELSA RS has a sampling frequency of over 3,500Hz that is packaged in 60Hz macro-samples and averaged for each discreet pedal revolution. The result is that, at a cadence of 90rpm, data is sent to the recording device every two-thirds of a second. There’s no need for faster sampling though as ANT+ devices can only record and display data once every second, plus there’s little value in real-time power measurements.

The carbon crank arms of the ELSA RS are constructed using SRAM’s Exogram technology. Each arm is hollow, providing some weight loss, while the broad cross-section improves stiffness, making for an attractive strength-to-weight ratio. I neglected to weigh the crankset sent for review but according to SRAM, an ELSA RS crankset with a GXP axle weighs 616g; fitting Dura Ace 9000 chainrings will add another 141g.

The ELSA RS is powered by a CR2032 battery that has a promised life of around 300 hours, is widely available, and cheap to replace. Accessing the battery is simply a matter of unscrewing the cap with the big Q on it and while this is supposed to be a tool-free operation, I needed to use a set of pliers.

Quarq warns against the use of tools as they can damage the compartment, so heavy-handed home mechanics should take extra care when it comes time to replace the battery. A cap design that was easier to grip would solve this problem altogether.

Finally, the ELSA RS has an IPX7 waterproof rating, which means it is resistant to immersion to a depth of one metre for 30 minutes. For more information on the ELSA RS, visit Quarq for details on the cranks, FAQs and product manuals.

Installation

Installing the ELSA RS crankset was no more difficult than any other crankset, and aside from ensuring a compatible bottom bracket was installed, there were no special precautions or considerations. Shimano’s HollowGlide chainrings were also easily installed, though home mechanics will need to have a set of Torx keys on hand for the bolts.

Installation of the cadence magnet is best done before the cranks. Three styles of magnets are supplied with the ELSA RS crankset: one is fitted to a ring that is compatible with threaded bottom bracket cups, another is attached to a slotted fork that will slide under a standard bottom bracket cable guide, and finally, there are a couple of buttons that can be mounted on the frame with putty.

The magnet needs to be mounted 2-8mm from the spider of the cranks in line with the marked sensor zone. Quarq’s online manual provides plenty of guidance, however there is no convenient readout (like an LED) to confirm that the magnet is doing its job.

There is a LED situated in the spider of the cranks that provides information on the status of the power meter. Back-pedalling a few times activates the power meter and the LED will flash, unless the battery is dead. More than one flash indicates an error in the system.

Once activated, the power meter is ready to be paired with any ANT+ device. For this review, I used Garmin’s Edge 510 and it only required a few moments to detect the power meter. After pairing was complete (~15 seconds), I was able to view and record my power output, and provided that I didn’t select a cadence sensor, I was also able to view my cadence, regardless of whether a magnet was installed or not.

On the Road

Putting the ELSA RS to work was a very simple matter. As described above, all that was required was to activate the power meter and pair it with the ANT+ device. After that, the interface of the device took over, and in this regard, Garmin’s Edge 510 was a pleasure to use. Every process from acquiring a GPS fix, customising fields, or viewing ride data was quickly and easily executed using a combination of the 510’s touch screen and buttons.

Quarq recommends zeroing the cranks before every ride. Just as anybody using a set of scales checks that they are reading zero before stepping onto them, so it goes for a power meter. The ELSA RS has a built-in Auto Zero function that is activated by spinning the cranks backwards five times then pausing for more than four seconds. The LED in the spider flashes as the power meter is zeroed — a matter of a few seconds — and then it is ready for use. This function can be performed while coasting on the bike, but is best performed before setting out on the ride.

Alternatively, and preferably, the cranks can be manually zeroed using the head unit before clipping into the pedals. I found myself incorporating this step into my start-up routine for the Edge 510 where all I needed was one or two minutes to ensure all sensors were up and running. Once the power meter is “calibrated” (the Edge 510 refers to this process as “calibration” rather than “zeroing”) a value is reported on the screen; values greater than 1000 suggest a malfunction. Over the course of the review period, my calibration values ranged between 20 and 90.

I have to admit to suffering a certain amount of data-induced blindness while using the ELSA RS cranks. After more than 25 years of road cycling, this was my first experience with a power meter and I had a lot of data at my disposal. I was fascinated by the power balance data and curious about the number (in watts) that described each of my efforts. I wasn’t oblivious to the world around me, but I wondered on occasion if the little screen on my handlebars wasn’t as distracting as a mobile phone in the hands of a driver.

The most important aspect of a power meter’s performance is consistency, such that a 250W effort made on one day is also measured as 250W on another, regardless of the interval in between. Unfortunately, the only way to judge this is with dedicated lab equipment over a range of loads, which is well beyond the scope of this review.

Reviewing the Data

Quarq does not offer any software for viewing or analysing power data but there are already plenty of options available such as Golden Cheetah and TrainingPeaks. I took advantage of Garmin Connect to upload my ride data from the Edge 510.

In addition to reporting averages, Garmin also adds some metrics developed by TrainingPeaks such as normalised power, intensity factor, and training stress score to help with analysis. However a good handbook and/or an experienced coach are recommended to fully realise the value of a power meter for training and racing.

Final thoughts and summary

At around $1,900, the ELSA RS is an expensive product, but it is in line with other crank-based systems. There is a risk that some buyers will get frustrated as they contend with the cost of all the necessary extras. Similarly, the compatibility of the cranks for Shimano chainrings will attract riders using Shimano’s 11-speed groupsets only to frustrate them due to an incompatible bottom bracket axle.

Both issues are easy to forgive though, because the system is easy to install and simple to use while promising a high degree of accuracy.

WRAP-UP

Elegant

The ELSA RS power meter is easy to install and when paired with Garmin's Edge 510, provides power data with a minimum of fuss. The crankset is supplied as a base model requiring a variety of extras, ranging from chainrings and a compatible bottom bracket to an ANT+ enabled device to collect and display power data, adding significantly to the purchase price. Regardless, the ELSA RS is elegant in its simplicity and functionality.

GOOD STUFF

Easy installation
Simple zero function
Reports share of work done by each leg

BAD STUFF

Variety of extras are required
GXP or BB30 axles only
Incompatible with some bottom brackets

CTECH RATING

8.9

Form

8.0

Function

10.0

Marketing claims

8.0

Serviceability

9.0

Appeal

8.0

USER RATING

Not enough user ratings to show averages

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REVIEWS () COMMENTS (36)

Tags: powermeter, quarq

Eric Zxg

This is the opposite of the trend of power meter. The power meters are getting cheaper and cheaper. The cheaper power meter is just as accurate as the more expensive one. If there is no sponsorship, who would spend twice of the price of a Stages to buy a Quarq?
- Seb
  
  In terms of accuracy- Stages is slightly less accurate than something like a Quarq, the degree to which is dependent on how much of a power imbalance the rider has between legs (everyone does to some extent, and at the end of a long ride this can become more exaggerated). Having said that, the main thing is of course consistency, and Stages should give you that, it just won’t be quite as accurate purely because it is doubling one leg. What will be interesting is in a few months time when alternatives like the 4iiii precision and Watteam Powerboat (amongst others) come out- I’m hoping prices across the board will drop (even Stages will be forced to). For me at the moment, Stages isn’t an option (SRAM carbon cranks on BB30), so my only options would be a used Quarq, Powertap or Vectors (reluctant to do the last two due to being stuck with wheels/pedals)
  - xponti
    
    Seb, Stages is still an option, you just fit the Rival crank arm onto your existing crank. The SRAM Cranks all have the same fixing system from crank to crank I believe. You will just have a carbon Crank on the Right and an Aluminium one on the left. I am looking at Stages for my bike and I run a Force Crankset.
    - Seb
      
      As far as I know it’s only an option if you’re running a GXP bottom bracket? I’m running Red (2013, yaw, 10 speed one) with a PF30 bottom bracket so pretty sure I can’t- happy to be corrected though! I’m pretty excited about the newer one’s coming out personally and prepared to wait a little longer anyway
      - andy
        
        If the only option is GXP (and you wanted to use the stages) just use adapters or a conversion BB (defeating the purpose of a PF30) to use GXP crank - then you’re good.
    - Seb
      
      Actually having had a look, seems like the Cannondale BB30 Stages crank might work- obviously it involves having a different non-drive side crank so would look a bit weird, but I think it would work
  - salty
    
    Check out power2max classic http://power2max.com.au
    
    Spider is about $800 and will fit onto your existing cranks/rings.
    
    As accurate as Quarq and reliable as SRM. Germans do it right.
    - Seb
      
      This one here (http://www.power2max.com.au/product/power2max-power-meter-without-cranks/)? Their compatibility list doesn’t list SRAM Red at all- not sure if it’s complete though. Otherwise this one here (http://www.power2max.com.au/product/power2max-type-s-sram-s900-force22-power-meter-without-cranks/) is $1300 and is comparable with SRAM (doesn’t specify red but presumably if it works with Force, will with Red too). But yeah, I have had a look at them and they look pretty nice- DC rainmaker loves them (http://www.dcrainmaker.com/2013/01/power2max-power-meter-in-depth-review.html) which is always a good sign too…
      - jo
        
        Sorry. The reason it doesn’t work with Sram Red is because the spider is integrated to the crank arms.
- nutty professor
  
  @Eric Zxg:
  
  Your post identifies your naivety with regard to power meter technology. Stages are not much better than a heart rate monitor, after you take into account the imbalances in stroke when standing, sitting, fatigued, fresh.
  
  The +/- 2% accuracy of Stages can easily blow out to 5 or 10% if your stroke varies. And when we’re chasing in the realm of 5-10% improvements over the course of a season, well you should be able to work out why a Stages isn’t great.
  
  This imbalance is completely unknown if you’ve never used a power meter that reports aggregate power and can split upstroke/downstroke or left/right power. You’re left with an expensive HRM.
  - velocite
    
    Stages is infinitely better than a HRM for measuring power, but quite poor at measuring heart rate! Invalid comparison really.
    
    While the one legged approach of Stages obviously fails to reflect any left/right imbalance, after 10 months experience with Vectors I don’t notice much variation in mine, either during a ride or from ride to ride. And surely what you’re after is an indication of changes over time, so unless your training is quite strange one legged metrics should be fine.
    - nutty professor
      
      Average figures will tend to hover around the same however you will notice slight discrepancies in balance when sitting/standing, fresh/fatigued, high/low cadence… etc.
      
      For instance if you’re reading 48/52 in one effort, and 47/53 in another, you end up reading 2% low on the left side. Add that to the +/- 2% and then you are talking a reasonable error in measurement.
      
      The variance doesn’t have to be more than 1-2% to make a significant difference.
      - Dave @ radelatide
        
        I’m missing my left leg, will stages still work for me?
  - seano
    
    Ok We’re having the accuracy versus repeatability argument again. Repeatability trumps accuracy unless you need to compare athletes (ie you’re a coach) or across bikes.
    - nutty professor
      
      We’re talking accuracy and repeatability.
      
      The same athlete will end up with erroneous power readings due to unknown variability in power.
      
      But what would I know, I’ve had a Stages and moved to something else, and actually have a practical experience with the whole shebang.
  - Nitro
    
    With Movistar on Power2Max (only measures one leg) and Sky on Stages (ditto), is it that cut-and-dry in relation to which one works / which doesnt?
    
    I well understand the world of commercial sponsorships and endorsement fees, but with a team as well backed as Sky, would they use Stages if it didn’t work for them?
    - JCJordan
      
      Power2Max do not have a one leg unit. Moviestar were using Power2Max to compare against the Rotor single leg unit. A experiment which did not seem to last very long.
- Isaac
  
  Stages are a joke, ask anyone who’s used one in the rain.
  - Nitro
    
    So THATS the reason why Froomey kept falling off on the wet roads of the TdF - I was wondering… :)
  - dbranson
    
    I have used Stages for over a year and I have not had problems riding in the rain with Stages or after washing my bike. Overall I would recommend Stages.
    - Rowdy
      
      I second that. Been caught in a huge downpour and the Stages didn’t miss a beat.
Jim

I’d be kind’ve interested in a nerdy-techie sort of way to see how under performing I am compared to the pro’s but not going to spend to 2 gorilla’s on a PM.

More interested in the lower end of the market such as:
1. Brim Brothers 999USD (but you’ve got to have speedplay shoes) probably too rich for me
2. 4iiii precision 399 one side or ~750 USD for 2 sided if it fits
3. Watteam Powewr beat $499 (two sided crank attached)
Chris Lee

“After more than 25 years of road cycling, this was my first experience with a power meter and I had a lot of data at my disposal.”

Surely you can find someone more qualified to review a PM, potentially someone who has used one before…Getting a novice to review such an item is a waste of everyones time.
- Matt Wikstrom
  
  Not sure how you’d judge somebody’s qualifications for any review, but if Wade trusted me with this review, then I’d hope the readers could do the same. I will only ever get to write one review as somebody that is new to power meters, and I think that is a worthwhile perspective to offer our audience.
  
  I’ve also had 20 years experience using sensitive lab equipment to measure cell function. What I lack in familiarity I more than compensate with instrument experience. What impressed me with this instrument was that it worked straight out of the box with a minimum of fuss, and was equally reliable on a day-to-day basis.
  - http://www.cyclingTipsBlog.com cyclingTips
    
    @disqus_i5eIdKipOd:disqus I absolutely trusted Matt with this review before going in, and I did read over it carefully to see if there was anything erroneous or if there was anything I could add (I’ve had about 15yrs of powermeter experience). I felt that Matt did an excellent job and came up with many insights that I often miss because I don’t zoom in on some details anymore. New experience offers fresh thoughts.
Winky

Still unspeakably ugly, like all power meters. Why do the spider shapes almost, but not, line up with the chainring spider bits, leaving those steps? Why is the large circular disc not sculpted away between the bolt holes to make it less obvious? Why did they almost, but not, match the finish of the chainrings? Does the battery holder need to be so obvious? Like all of these things, it still looks like a prototype.
- zorp
  
  Cause those are Ultegra chainrings, ya nincompoop. They’re best mated with the DA 9000 rings
  - Winky
    
    Still ugly. There are still plenty of other things I’d rather spend my money on.
- RayG
  
  The disc contains the strain gauges.
  - Winky
    
    Ahh. OK.
Emil

You list that it only comes as BB30 or GXP and therefor not compatible with certain bottom brackets? That is the case for all kinds of crankset, wether it is Sram, Shimano or Rotor.

A GXP crankset will fit 99% of all modern road bike frames on the market. But you would of course need the right bottom bracket to make it fit.
Andy Logan

I have the new Riken and have been getting power drop out issues of late. Anyway else been getting the same and can recommend a fix?
Monza Imports Cycling

All quarq cranks are able to be installed on BB386 frames. Quarq does not list it on their website, but from our testing and installation, we can confirm that the BB30 versions of the cranks does work on bikes like the BH Ultralight and BH G6 aero.
RayG

You mention “Shimano’s HollowGlide chainrings were also easily installed, though home
mechanics will need to have a set of Torx keys on hand for the bolts”, but you’ve failed to mention the need to torque the chainring bolts evenly. See page 16 of the user manual (http://quarq.com/media/files/mt_95-6118-008-000_rev_d_quarq_power_meters.pdf).

This has been discussed a lot on the Wattage Google group. It’s recommended to use steel bolts to allow the torgue to be high enough, as well as carbon paste between the rings and the spider.

Sounds like a PITA, although easy enough once you’ve done it a few times, but maybe CT should have ‘zoomed in on the details’.
- Matt Wikstrom
  
  I just tightened the bolts as I would for any other crankset, and aside from suggesting a maximum torque, the user manual does not set out any special requirements for installing the chainrings. Sounds like the Wattage group have made installation more complicated than it really needs to be (certainly the paste is overkill). Quarq warns that it may take 2-3 rides for the chainrings to settle in every time the chainrings are changed.
Monza Imports Cycling

Hi Everyone

Since the release of the Quarq Elsa RS, Quarq have been able to release a few updates on the unit.

1) Although we didn’t offer them upon release, we now have ELSA RS in all six crank lengths: 162.5, 165, 170, 172.5, 175 and 177.5.

2) ACCELEROMETER CADENCE

Quarq have been working very hard on accelerometer cadence for a while. The accuracy
and performance of the magnets and reed switches is very high and that sets a high standard for expected performance.

Quarq have been using it on mountain bikes, cyclo-cross bikes and road and TT bikes. Quarq and SRAM have pro cyclo-cross racers using it this season. Quarq has racers using it in Mountain Biking’s Enduro World Series.

Performance is excellent up to 160rpm and in all but the most extreme vibration environments. The best example of an extreme vibration environment is roadside rumble strips.

Benchmark tests show the accuracy matches or surpasses other products that use accelerometers for cadence.

In terms of accuracy, in the worst cases, single pedal stroke cadence accuracy decreases by a maximum of 2%, but cumulative accuracy is unaffected. There is little or no impact on cumulative power values such as kilojoules, average power and normalized power.