Quarq Power Meter and PowerTap G3 Hub: How to Choose

by Patrick Davis

Power Meter ComparisonHere are my thoughts on choosing between a Quarq power meter and PowerTap G3 hub.

I am somewhat of a geek when it comes to techy training equipment. I like to use it and get general baselines, but don’t get too wrapped up in analyzing every aspect of training. My mentality is to do what's on the schedule, take a quick look at the data and bank it, and then forget about training until the next time around. I feel like it keeps me a little level headed.

Fortunately, working at a bike shop and liking to play with new gear go together well. In the past, I have owned a Quarq S975 and PowerTap SL+ but have gotten rid of them as wants and needs changed. (Things like buying a car or deciding not to race anymore change financial priorities.)

I recently got back into specific training, which meant buying another power meter. Yay for expensive toys! I ended up getting the standard PowerTap alloy wheelset with a G3 hub. In my opinion, it is the best bang for your buck power meter out there right now.

About a week after getting the PowerTap I was talking with the SRAM rep, who was showing off the new Quarq Elsa power meter. I got the whole speech about the updates and how awesome it is, and I took a shot in the dark asking if I could ride it for a bit. To my surprise he let me keep it for a week! Needless to say my bike easily doubled in price for that week.

Going off my experience with both, here is a general overview of what you should think about when considering a power meter purchase.

How much should I expect to spend?

This question is usually answered with, “It depends on what your needs are.” Prices go up with what it tells you, how it tells you, and its compatibility.

Option 1, Crank Based: $1795 - $2045
Get this if you frequently change wheels for racing or different conditions.

Option 2, Rear Hub Based: $1300 (hub) – $3200 (carbon wheelset)
Get this if you are cool with swapping wheels for different bikes.

If you are not too particular about race day wheels or do not want power on race day then you save some money with the PowerTap.

Is the data produced by QuarQ and PowerTap the same?

Basically, yes. The only cool option Quarq offers is Omnical Power Balance. This shows left and right power balance to show inefficiencies in your pedal stroke.

For my time with both the PowerTap and the Elsa, I had a Garmin 800 on the PowerTap and an 810 on the Elsa. The rides were all on the trainer with the units calibrated by the manufacturers’ specifications. Take a look at the following images to see how they read differently.

PowerTap G3 Data on Garmin 800 PowerTap G3 Data on Garmin 800 (Click for larger image)
Quarq Elsa Power Meter Data on Garmin 810 Quarq Elsa Data on Garmin 810 (Click for larger image)

They were super close in this example ride with no crazy jumps or much coasting. Overall, being within 2 watts average seemed pretty darn good. Or at least good enough for what I need to train efficiently.

Comparison of Quarq Elsa and PowerTap G3 Comparison of Quarq Elsa and PowerTap G3

 

How compatible are they?

Both are completely wireless and transmit signals via ANT+. There are many options based on what your needs are. All of the Garmin Edge and some of the Forerunner models have ANT+ technology. My favorite is the Edge 510. The battery life is great and the fields are very easy to view and change on the fly. Other options include the newer CycleOps Joule computers. Both are ANT+. The newest available options are getting an app for your smartphone. If you have an iPhone, the Wahoo Fitness App and Wahoo Key ($59.99) are awesome. So the key is to find something that is ANT+ compatible and you are good to go.

The next thing to consider is other sensors. The Quarq uses cadence as a metric to calculate power, so that will automatically be given with included cadence magnet. If inside, or if your head unit is not GPS compatible, an additional sensor for speed is necessary if you want that metric.

The PowerTap G3 also uses cadence in its power calculation. It is not figured based on pedal revolutions, but through force trends applied to the rear hub. It also calculates speed based on wheel size so there is never a need for a GPS computer or extra sensor on the frame.

What other specifications will help me decide what is best for me?

Here are some general specifications of each:

Quarq

ANT+ compatible
Comes in GXP and BB30/BBright/PF30 versions.
Easy to change, no tool, battery. CR2032 will last about 300 hours of riding.
Omnical Power Balance
+/- 1.5% accuracy (for Riken and Elsa)
Qalvin App for Diagnostics (requires Wahoo Key)
Analysis software: Training Peaks, Training Peaks WKO+, Golden Cheetah, Strava
Warranty:  I have not experienced using it but hear it is pleasant and quick.

Zeroing: Quarq recommends zeroing your power meter before each ride to compensate for environmental changes. If readings seem incorrect during rides, Quarq also recommends doing a zero while riding.

In my opinion, this seems super annoying. A $2k bike toy essentially needs “fixed” each ride, at least once per ride, to get accurate information. I am not a fan of this.

PowerTap

ANT+ compatible
Head unit calibration may be needed, but hub should not need attention. If it does, it must be sent into CycleOps for servicing.
Compatible with Sram/Shimano and Campagnolo
200 hour battery life: CR2032
Warranty: I have not personally used it but have sent items in for customers and it was quick and painless.

The new G3 design moved all computing to the hub exterior. This means temperature can easily affect power readings. I had some trouble early on with erratic readings when cold. For a whole ride it said I was doing 1 watt. I got on the next day and everything seemed to work fine without issue and has worked flawlessly since then. I have yet to figure out what caused that but am happy the problem did not continue.
So it all comes down to a few questions and how much money you want to spend. Do you compete a lot and have a need to switch wheels often? Or are you OK with having a pretty good wheelset that is your only option for riding with power?  Another thing to think about is if you want to use it on multiple bikes. If you get a crank be sure your bikes are compatible. If not it will be stuck on one bike.

In the end choose the one that gets you the most use and least amount of regret.

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Katherine is our Content Champion. She has done triathlons in the past, and now focuses on mountain biking and long-distance gravel riding. She still has a soft spot in her heart for weird multi-sport events like indoor triathlon and aquabike. She also teaches indoor cycling.

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  • Nick

    I have a g3 powertap but the battery life is not lasting very long , this is all new to me as have been training to hr, when I commute to work my bike is left inside where it's warm and then when cycling home it's cold especially this time of yr, is there an issue with the difference in temps . My calibration figure shows 426 when I first got it it registered 500 can I just have some advice on dealing with different temps please .

  • Patrick

    Hey Nick,
    How often are you replacing the battery? It should be good for at least a few months, if not more before needing to replace it.

    As for calibration and power reading, yes temperature effects the G3 hub a lot more than the older style hub. This is due to the brain now being located on the outside. Even riding on the trainer in my cold basement shows some power drift from the beginning to end of a ride where the temp changes a few degrees and the equipment gets warmed up.

    The only advise I have is to calibrate often and make sure your hub is updated to the latest firmware edition. You can check that at www.powertap.com.
    Thank you