The carbon windows are gone, and the weight is way down. ©Cyclocross Magazine

The carbon windows are gone, and the weight is way down. ©Cyclocross Magazine

by Josh Liberles

PowerTap has long been a big player in the power meter market, but the distinctive oversized hubs are a relative rarity on the cyclocross course. While there are plenty of ’crossers who train with PowerTaps, most of those who choose to race with power typically opt for one of the crank-based meters like SRMs or Quarqs.

Part of the knock on PowerTaps was their weight. Another factor is the added expense of needing a PowerTap hub in a training wheel and at least one – perhaps several – race wheel. The new G3 PowerTap hubs tackles that first drawback head on. According to Eric Wallace of Saris, PowerTap’s parent company, the new hub is the lightest power meter on the market, adding about 100g to a comparable high-performance rear hub.

The other big change in the new generation of PowerTaps is that the electronics and ANT+ transmissions have migrated to the end cap. Because of that, the tell tale carbon windows of the old models have been replaced by aluminum in both the svelte G3 and less expensive Pro models.

The new hubs only add about 100 extra grams to this carbon Enve wheel. ©Cyclocross Magazine

The new hubs only add about 100 extra grams to this carbon Enve wheel. ©Cyclocross Magazine

PowerTap is making a run at the race wheelset market, and they’ve using Enve rims to build up some impressive hoops. The tubular Enve 45s (45mm deep carbon rims) built up with a G3 rear PowerTap hub weigh in at a scant 1250g per set – impressively light for wheels without a power meter. They’re available as tubulars or clinchers, in 45mm or 65mm rims. Whichever variant you choose, the price is the same: $3,499. The hubs are also convertible to disc, if you’re at the ready for a hydraulic stopping solution. The G3 hubs are due to be available to the public on October 15th.

At the training end, PowerTap is building a wheelset on the Velocity A23 rims, which we looked at during Interbike 2010. The A23s are clinchers with wider rims – 23mm inside diameter. They come built with a Pro rear hub to make beefy training wheels for all-around riding for $1,100 per set.

More ’cross racers are competing on power meters in general, and PowerTap is starting to get in on that party. Russel Stevenson, who won the Raleigh race this summer and received a pro contract as his reward, is racing on PowerTaps on Enve rims this season, and we expect to see other high profile riders follow suit.

The new Joule has gone on a crash diet too, in size and price. ©Cyclocross Magazine

The new Joule has gone on a crash diet too, in size and price. ©Cyclocross Magazine

Revamped Joule CPU
The old version of the Joule was, frankly, ginormous. It also cost $500. It’s now substantially smaller, lighter, has a more user-friendly mounting system and costs just $199! ($249 with GPS functionality). That’s quite an update. The CPU can pair with any ANT+ power meter, and it displays current, max and average power; cadence as measured in the hub or by a sensor; speed; and GPS functions in the upgraded model. A nice feature for power geeks is that the Joule’s internal computer will crunch the data as you ride and calculate the normalized power and training stress score on the fly – that’s something that typically can only be guesstimated until a rider gets home, downloads and runs the numbers through software like Training Peaks WKO+ or Golden Cheetah.

The new PowerCal: The Power Is in You! ©Cyclocross Magazine

The new PowerCal: The Power Is in You! © Cyclocross Magazine

I’ll say it up front: I’m skeptical of anything that tries to estimate power without actually measuring power. But that’s exactly what the PowerCal claims to do. The numbers are based on a correlation between power and heart rate, and there’s some custom calibration that needs to be done for each rider up front at a dealer shop, and periodically thereafter, to make sure those metrics are in sync. Allen Lim, one of cycling’s preeminent physiologists, has attached his name to the project, which certainly gives it come clout.

Wallace cited a CU Boulder study which places the devices accuracy at +/- 8%, and says that figure has been independently validated (compared to +/- 1.5% for the PowerTap wheels, which Wallace claims are significantly more precise than competitors meters). Eight percent is quite a bit – but for $200 total for the system, “you get a taste of training with power,” says Wallace. Sounds like a gateway drug to me, and Wallace was actually quick to agree. While in this case the first one isn’t free, it’s pretty darned cheap.

The Joule extends right from the stem. not sure it's UCI legal, but it's really neat! ©Cyclocross Magazine

The Joule extends right from the stem. Not sure it's UCI legal, but it's really neat! © Cyclocross Magazine

Integrated Fun: 3T and PowerTap Project Bike
PowerTap and 3T got together for a one-off bike project to explore some ideas they each had for product integration. The result: 3T Meta cranks with ANT+ cadence built into the crank arm (pretty cool!); a custom 3T Newspoke wheel with the PowerTap torque internals intergated in 3T’s hub shell; a stem setup with the Joule CPU built into the front. This is one of several projects that PowerTap is pursuing, but the idea of each is similar: partner up and integrate. This one may be a road bike, but of course the principles would be the same on its more knobby brethren.

Want to see more of Interbike’s cyclocross offerings? We have a full list of some of the best new products we saw at Interbike, with more being added every day.

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