My Power2Max experience

Once I got the all-clear to resume riding and training from my Doc, I knew that a power meter was going to be part of the equation. Being able to quantify and track my recovery and progress is invaluable. But which meter to get? I had purchased a Power Tap wheelset from a friend, but after a couple weeks I realized that I’d probably never race on that wheelset and I definitely wanted to know my power output during a race. The logical solution then became a crank-based power meter system.

I started researching the different options and up until March I knew of only two crank-based power meters: Quarq and SRM. The Quarq is what a lot of my buddies had; it’s affordable and easy to use. However, I have heard on more than a few occasions that people have had issues and had to send them back. I’m not a fan of having to send things back repeatedly. The SRM is considered by many, including the authors of “Training and Racing with a Power Meter,” Hunter Allen and Andrew Coggan, PhD, to be the “Gold Standard” of power meters. It’s been around for over 20 years. It’s reliable and accurate and SRM seems to have worked out any substantial issues. The battery is not replaceable, so once a year you have to send it in to SRM to get calibrated and a new battery installed. Doesn’t seem like a bad deal. The issue I had with the “gold standard” was that it was priced like it was made of gold! The SRM was out for me, it’s way too pricey.

Late one night, while trolling the internet, I discovered another option. A company called Power2Max makes a crank-based power meter and had just started distributing in North America. It’s a German company and they have been making their meter for a couple of years but it had only been available in Europe. Over the winter they sent a rep to set up shop in North America. Why they picked Vancouver, British Columbia I don’t know! I kid, I’m sure it’s great there. Anyhow, through my diligent research I read some early reviews and comparisons and heard about “drift.” Somewhere on the internets a reviewer claims that the Power2Max readings shift because the strain gauges don’t respond well going from a warm indoor setting to the cold, harsh outdoors. Message boards threw up hypothetical situations of climbing thousands of feet where the temp changes dramatically in the course of a ride and you absolutely had to keep pedaling and therefore it would “drift.” The more I read, the more questions I had. The price on the Power2Max was amazing, was it too amazing? Was it a sub-par product and that’s why it was a good deal?

One of the best ways to get answers is to go straight to the source. I e-mailed the Power2Max rep, Michael Wegner, and immediately got a reply. We began a dialogue over the course of a few e-mails and I felt like it was legitimate product and my confidence grew tremendously. I took one last look at the SRM and Quarq but I confidently decided to go with Power2Max as my power meter. One of the main reasons was Michael’s great customer service. If I had a question, it was answered immediately. Throughout the whole ordering process Michael kept me informed about what was going on. Having been in sales previously I really appreciate excellent service and Michael and Power2Max certainly delivered that.

I opted for the Rotor 3D+ crank in 170mm crank arms and a 130 BCD Power2Max. It doesn’t come with chain rings, which is fine because I like SRAM’s Red rings and their black version goes great with the meter. Freshbikes in Arlington installed the crank into my new Cervelo S5 and I was off and running. One of the first things I noticed was the amazing responsiveness of the drivetrain. It’s stiff. It goes when you stomp on it. I am no expert by any stretch, I just know what I feel. This bike with this crank is by far the most responsive, most solid pedaling I have ever felt. Hard efforts are rewarded with great acceleration and speed. I love it.

The crank is great, but what about the meter? That’s why I got the thing, right? Have I experienced “drift” like people say? In plain, simple language: no. After two months of use I have no reason to believe my power readings are inaccurate. I have not experienced any erroneous readings due to drift or any other crank-related issue. I use the Power2Max paired up to a Garmin Edge 500 head unit. My power when I first got it is right there with what I was doing with a PowerTap. Luckily after two months of riding, my power seems to be improving ;-)

Where does this drift issue stem from? Cranks and power meters and strain gauges are all made from metal. Metal is susceptible to changes in temperature; it expands and contracts. Have you ever noticed when you go over a bridge there are metal gaps in the pavement? That’s to allow the bridge to flex and handle the temperature change. How does a crank-based power meter handle the change? They offset the change by zeroing the readings from the strain gauges when there is no load. Each manufacturer does it differently. I’m told with Quarq you pedal backwards twice. Power2Max auto-zeroes every time you stop pedaling for two seconds. According to “Training and Racing with a Power Meter, 2nd Edition,” with the SRM “(the rider) must create a ‘zero-offset,’ or ‘zero-point’ to ensure that the wattage will be zero when there is no load on the power meter. This is a FIVE-SECOND procedure and can be done throughout the ride with no detrimental effects to your data.” Here’s a pic of that paragraph if you don’t believe me:

They go on to say “This only tends to be a problem when a bike goes from 70 degrees Fahrenheit while parked inside a house to a much colder 40-50 degrees outside. It is a good idea to park your bike outside for ten or fifteen minutes before beginning your ride so that the metal of the crank and the strain gauges can adjust to the correct temperature.”

Here’s what I take away from this: ALL crank-based power meters and their strain gauges can be subject to drifts in readings in the event of a huge temperature swing. ALL drift will settle down in around 15 minutes when the metal gets used to the temperature change. Each meter handles things differently. It’s how the power meter and gauges handle the drift that matters. In my own, personal experience, the Power2Max is amazing. It auto-zeroes every time I stop pedaling for two seconds. I don’t have to do anything else. I don’t even have to get off the bike. I don’t even notice it.

Let me be crystal clear: I’ve never doubted the capability of the Power2Max to auto-zero and I’ve never doubted it’s capability to properly display my power readings. It is a terrific crank and a great power meter. It even has a cadence sensor built-in, what’s not to love? If I had it to do over again and all three crank-based power meters cost the same amount of money, I would get the Power2Max. Every time.

I’m not an engineer, I’m a photographer and an amateur cyclist. I have no independent test lab nor do I own four different power meters to test side by side and show you charts. I like getting the most for my money and I do diligent research when I make major purchases. The Power2Max works for me and I’ll continue to be a customer of theirs because of the great customer service experience I received.

Just do me a favor, will you? Shut up about the drift already. It’s a non-issue. Sheesh.

Here’s my crank:

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About jaywestcott

Professional photographer, amateur cyclist, and occasional player of the blues.

Posted on May 28, 2012, in Uncategorized. Bookmark the permalink. 3 Comments.

  1. Thank you so much for your review on Power2Max. I would say P2M is at the same accuracy as SRM because I have both.

  2. Any further advice on how the power2max has been performing. I, too, am thinking about one, and had similar questions regarding drift.

    thanks

    jeremy

  3. Hi Jeremy,

    I’ve had my Power2Max since the end of March and it’s been amazing. I’ve had no issues with drift, as I stated above in my post. They are coming out with an update that will do two things: it will add a temperature sensor to help with adjusting and zeroing for temperature changes and then a left/right power distribution sensor, which I’m actually pretty excited about. After the surgery I went through I would love to know how my left his is doing power-wise compared to the right. The updated model should be available shortly, contact Michael at info@power2max.ca and he’ll hook you up.

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