Power Meter Research

I've been using my iBike Power Meter since 2006. Although it works reasonably well, it has some weaknesses that cause me to sometimes doubt the data that's collected during a ride. Also, reading about the new Quarq power meter has got me thinking about buying a new one.

First, I should clarify what I'm trying to accomplish by forking out the cash for a new power meter. I'm looking to improve the reliability of measurements from my iBike, or rather, eliminate my doubts about those measurements. Let's assume my iBike is 90% accurate as a function of time due to fluctuation in my position on the bike, or inaccurate wind speed measurements. The questions are is that even an issue? If so, how much money is that really worth?

Here is a comparison of Powertap, Quarq, and iBike. Well, there's not much difference between the measurements. The idea that more money = better performance might not have basis in fact. So if I buy a new force transducer type power meter, I might still have doubts about the data that I collect.

iBike

Some iBike reviews:

• My three year review
  
• Competitive Cyclist Review
  

Is there any merit in upgrading the iBike to one of the newer versions? The top of the line iBike is about $900 by the time you add all the options. That's starting to get into PowerTap territory. What new features does it have that justify the extra long green.

• Wireless
  
• ANT+ Compatibility
  
• ability to combine data from multiple sources, like GPS, HRM, and a force transducer power meter with novel calculations.
  
• Faster CPU, more accurate

The new iBike Stem Mount is a better solution that the bar mount that I currently have. The stem is less susceptible to vibration than the bars, plus the central location should be a better representation of air pressure differential than the offset position.

SRM

SRM is the gold standard power meter, but costs like it's made out of gold. At $3,000-4,000 more or less, there's no way I can justify that. Let's presume it's 100% accurate. What value does the theoretical 10% have when my power data is only comprehensible when viewed through the hazy lens of subjective personal experience? Moving on!

Power Tap

The PowerTap is more reasonably priced (by far) than the SRM. One advantage over the iBike, is I could use the power meter with my cyclocross bike. On the other hand, one of the things I like about 'cross is that I don't use a computer at all. At that point of the season, I'm typically weary of analyzing power data and chasing after digits on a computer.

The problem with the PowerTap is that I would only be able to collect data with new wheels. I'd probably want a training set and a racing set, and a cyclocross set! So the price tag of the PowerTap solution gets steep quickly. The computer is about $300, and each hub is about $900 for the fancy version. Also, I just bought new wheels, so those just collect dust when I want to measure power. If I were about to upgrade wheels, that would be the time to think about a PowerTap.

Quarq

I like the Quarq power meter approach. It's got the advantages of force transducer measurement without the hassle. It's wireless, ANT+ compatible, and the electronics and battery are easily accessible. Plus, they are planning to release a bike computer with open source software! For me, that's awesome. Unfortunately, that's not available yet, but will cost about $1000. The price of the Quarq gauge is $1,495, plus you need to either supply cranks, or buy them from Quarq.

Only three crank types are currently compatible with the Quarq transducer, so I'd need to buy new cranks, so the price is more like $1,900 for the transducer and another grand for the computer. Ouch. $3,000.

I'll wait on that until they have the complete kit, transducer plus computer, and reconsider.

Ergomo

Ergomo seems like an interesting solution, but has loads of bad reviews from actual customers. That tells me stay way far away from it.

Bottom Line

Of the force transducer power meters, the Quarq power meter intrigues me. I don't like the limited crank set choices. I like the open source platform concept for the computer, though, and would be willing to pay to play around with that, since I'm a geek. The cost for the whole solution is steep, close to $3,000.

The new iBike is supposed to be more accurate than my first generation version. At $800-900 it's not bank breaking. But it will still have some of the deficiencies of my current unit.

If I get a windfall, I might spring for an iBike Gen III this summer, and in the meantime, I'll keep an eye on Quarq.