The CycleOps PowerTap SL requires a wheel with its own special hub, and adds significant weight as well. No thanks—I want to ride my favorite wheels that I already own. Cost is somewhere around $1000, depending on the wheel you choose.
When training with a power meter, heart rate relative to power output is a crucial measure of performance. Thus, it’s simply mind-boggling that neither the PowerTap nor the SRM units record altitude! At 6000-10000' in elevation, power output with respect to heart rate drops up to 15%. Without altitude data, the power data relative to heart rate is thus off by up to 15%, making comparisons at different altitudes very difficult. Worse, there is not even a crude record at which altitudes the measurements were obtained, so it’s a guessing game. Take a notepad, and scribble while you ride.
The Polar Power System ($300) works with their heart rate monitors, so if you already have a Polar S710i, S720i or S725X, it is appealing. And the Polar *does* record altitude, so power output can be analyzed taking altitude into account.
I have personally used the Polar unit, and while the data was of good quality and consistency, I had frequent problems getting the crank magnet to stay in place, so much so that I gave up on it and sold it. Installation is a real hassle too—I broke the cable doing it and had to send it for repair.
The newest entrant, the Ergomo Pro ($1600), shows great promise. It has a nice display, the lightest weight, records altitude, and has other goodies too. The Ergomo Pro is not compatible with Shimano DuraAce cranks, so the cost of a compatible crankset ($300-$600) must be added to the cost of the unit itself. Price aside, this is a major drawback to those of use who love the stiffness of the Shimano DuraAce crankset.
The Ergomo Pro unit uses locked software tied to a single computer. After spending $1600 for their hardware, you are treated like a potential thief with respect to the software—if you want another copy for another computer (say for a home desktop and a travel laptop), you have to pay another 40 Euros. There is also compatible software from Cycling Peaks, but I haven’t investigated it yet (and there is a free trial). I have inquired as to the multi-computer scenario.
But that’s only half of it. Lots of PC software is poorly designed and/or unreliable (crashes/bugs). So how do you determine if you’ll like or dislike it, or if it will even work reliably on your particular computer? Even a dealer can’t tell you, because to install the software, they have to use a license key from an in-stock unit, which makes it unsalable!
Problems abound with this “customers are potential thieves” locked-software approach:
- If you get a new computer, you’ll have the hassle of dealing with the license key issue;
- If for some reason you reinstall the operating system, you’ll have the hassle of dealing with the license key issue;
- I’ve seen keyed software go bonkers before, and insist the copy is illegal.
- You can’t carry a “just in case” backup disk, because you won’t be able to install the software elsewhere without another key;
- My MacBook Pro can boot Windows XP, or it can run Windows XP in virtualization software such as Parallels for Mac OS X. Without a doubt, keyed software will consider this two computers, even though it’s actually one.
- There is no way to try the software on another computer (say if you’re considering a switch), since it’s locked to the existing one.
Another problem is that the download mechanism is a serial port. Many laptops, including my MacBook Pro do not have a serial port. So you must use a USB-to-serial-port adapter. Will it work reliably? Who knows without trying the software!