Powertap power meter

A few years ago, I decided to have a play with using a power meter in my training. Because I wasn’t too sure about how useful I’d find this, I went with the cheap option – a Polar CS600X with WIND speed and power/cadence sensors. This worked reasonably well – at first – but I’ve had no end of problems with reliability. Mostly this seems to be because there are several essential components in the WIND power meter system: the power supply, the chain tension sensor, the cadence sensor and the chain speed sensor. If any one of these elements doesn’t work, you see no power or cadence reading, and there is virtually no diagnostics available to figure out where the problem lies (except if there is no power). And what is particularly annoying is that the setup can work fine one day, and the next (with the bike not moved from the turbo trainer) it doesn’t the next day.

Anyhow, enough was enough, and I decided to move to one of the more ‘serious’ power meter systems. I was looking for something that could be moved from one bike to another, that used ANT+ (I am so fed up with the Polar proprietary system), and that would be reasonably robust. I thought through the following options:

1. The Polar Pedal system. Not ANT+. Seems from reviews that the pedal installation is fiddly so not easily switched from bike to bike.

2. The Garmin Vector system. Despite winning a product of the year award from a bike magazine a few years ago, this hasn’t been released to the public yet and remains effectively vapourware. It also uses an undesirable (to me at least) pedal system – Look Keo – and may well be prove to be a fiddle to install the pedals as with the Polar system. At least it is ANT+. I should add that I’ve not got anything against the Keo pedals, but I’ve no desire to add Keos to collection of pedals that includes old-style Look, Campagnolo Pro-Fit, Shimano SPD and Speedplay!

3. The Brim Brothers system where the power meter is within the shoe plate – seems attractive, but what’s the release date? At any road, the system seems to use Speedplay shoe plates.

4. SRM – the industry standard crank based system. Clearly the system to have above all others, but it’s expensive and not easy to switch between bikes. It is ANT+.

5. Other players come and go…

6. Powertap. This is what I plumped for. I went for a Hed Jet disc wheel with a Powertap G3 hub. This is a spoked wheel with a permanently bonded carbon fibre cover bonded to the rim and hub. It seems to be a robust construction (though the skin is pretty thin and flexible), and I am proposing to use it while turbo training as well as on the road.

So far, I’ve had the device for a few weeks, and I can make a few observations. Firstly, the ANT+ system is a godsend, particularly as it relates to the Garmin 500 computer that I use. I’ve only used the wheel for a couple of events, as bad weather and a combination of leave and working away from home have interfered. I can observe that typical wattage is considerably lower than recorded on the old Polar system. But that’s kind of what I expected, and I am only using these data internally as there’s little point in comparing with other riders or power meters. I’d add that the Garmin 500 offers quite a bit of versatility in how data are displayed. I’ve decided to set one of the screens to include Power, Power (3 sec average) and Power (30 sec average). This offers not only an instantaneous power value, but a rather smoother and stable figure. The Garmin’s data are easy to import intoGolden Cheetah.

As a disc wheel, the Jet disc is different to disc wheels I’ve used in the past. My first disc was a Hed with a screw-on hub – this had a rather cardboardy feeling carbon structure and was hollow and symmetrically lenticular. This disc was sold and replaced with another version with a cassette (currently adapted for fixed gear use). I’ve also got a Corima disc, which appears to be a foam core with carbon skin, and is flat-sided. The Jet disc wheel is essentially a spoked wheel with a thin carbon sheet covering the spokes – sort of a fairing. It has therefore got something of an asymmetric lenticular appearance because of the wheel’s dishing. The skin feels a bit flimsy, particularly around the valve hole, but has stood up to use rather well so far. The skin is firmly attached to the hub and is bonded to the alloy rim. I chose a clincher version, as I’ve pretty much abandoned tubulars for all but the best of road conditions – around where I live I was suffering too many punctures in recent years. I imagine that a ‘normal’ Jet disc would be quite light though with a Powertap hub, even the lighter G3 version, the weight is a little hefty.

Expect a longer term review at the end of the 2013 season.