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LOOKing forward

Look and Polar launch KeO Power meter, for real this time

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Freiburg, Germany (VN) — Look and Polar are finally ready to ship the world’s first pedal-based power meter, the Look KeO Power. As the name suggests, the system is based around a Look KeO pedal, combining data from 16 pedal-axle strain gauges and an externally mounted Polar P5 accelerometer and sensor setup to calculate power. The system will cost $2,200.

Look and Polar invited a host of international cycling journalists to the Rad Labor test facility in Freiburg, Germany for a presentation on the new power meter.

The case for pedal-based power

Pedal-based power meters provide a solution to practical problems posed by crank-based or hub-based meters — SRM, Quarq, Power2Max, and Powertap all included. Most importantly, they are easier to install and move between bikes than a crank-based system, and they don’t limit wheel choice as a hub-based system does.

The latter is self explanatory: with a hub-based meter the only options are to lace a heavy Powertap hub into a burly training rim that isn’t ideal for racing, or into a light race rim that isn’t likely to last over extensive training, or buy two Powertaps. No solution is ideal. It is possible to buy two low-level Powertaps for the cost of a single KeO Power system, but weight remains an issue. The KeO power adds very little weight compared to a regular set of Look KeO pedals, and can actually be lighter if switching from a heavier set of pedals.

The perk of easy installation with the KeO Power has become increasingly important as the number of bottom bracket “standards” has exploded. Throwing down a few thousand dollars for a crank-based power meter becomes even less appetizing when it is far from guaranteed to work with your next frame. Plus, switching a crank-based meter between multiple bikes is a pain.

Pedal-based meters can also provide a data set not available from a crank-based or hub-based power meter: left vs. right power. This helps identify deficiencies and allow those deficiencies to be corrected.

Compatibility

Initially, the KeO Power system will only be compatible with Polar’s CS500 and CS600 series computers, using Polar’s proprietary WIN transmission protocol. The system will not be compatible with the Garmin-owned, open-source ANT+ protocol, so it cannot be used with any Garmin devices or the host of other ANT+ compatible head units. ANT+ is owned by Garmin, the company behind the upcoming Vector pedal-based power meter, so it is understandable that Look and Polar did not want to adopt a system owned by a direct competitor.

Instead, Polar is currently working with a host of other sports electronics companies to develop an open-platform, wattage-compatible Bluetooth Smart transmission protocol. Polar and Look plan to have the KeO Power Bluetooth compatible by late summer. For those that buy the system before then, upgrading will require only a firmware update — no hardware changes required.

The low-energy Bluetooth Smart system is already compatible with numerous smartphones, including the new iPhone 4s. Since the protocol will be open, any company can use it without licensing fees, so the number of available head units should increase drastically.

Saris, the company behind Powertap, is also involved in the development of the Bluetooth Smart power protocol, though the company’s involvement is no guarantee that they will actually drop ANT+. SRM has been rumored to be headed towards Bluetooth as well.

As of now, the Polar head units are compatible with the company’s ProTrainer 5 software (Windows only) and PolarPersonalTrainer.com, which is both Mac and Windows compatible.

Installation

The KeO Power has an auto-calibration function, performed automatically on startup. It accounts for temperature and other factors that can skew strain gauge readings.

Installation is relatively easy — certainly quicker than a crank-based system. The only difficultly lies in the fact that the axle must be aligned correctly with the crank for the system to calculate power correctly. Look’s solution is to mark the axle with a small indent, which must be aligned at 90˚ to the crank. A locknut in between the pedal body and the crank is then tightened down onto the crank to create a firm hold.

The pedal threads into a crank as usual, until the end of the axle is flush with the back of the crank and the mark sits at 90˚, then the locknut is tightened down onto the front of the crank using a regular 15mm pedal wrench. Look provides a special 8mm wrench to make the process easier — simply align the wrench with the crank arm and then tighten the lock nut. The method is considerably easier to perform than to explain, I assure you.

The cadence sensor is internal, so there are no extra magnets to mount anywhere. Crank length selection is performed on the transmitter itself.

As a contact point, wear is a concern with a pedal-based power meter. Thankfully, pedal bodies will be available separately from Look, so there will be no need to spend the full $2200 again in a few years when the contact surface wears out.

Accuracy and precision

Polar and Look commissioned an independent study performed by Rad Labor, a German sports science company associated with the University of Freiburg and the German Olympic program.

All three systems were tested extensively both indoors on an ergo bike as well as outdoors by elite riders. Rad Labor then compiled all the data and used the data that agreed between the three based on assessment. The study showed that the KeO Power system is on par with both the SRM and Powertap systems, accurate within 2%.

Precision increased as power rose, a feature designed into the system with the selection of strain gauges designed to be exceptionally accurate over 150 watts.

Look tests each unit before it is sent out of the factory to ensure that it falls within that +/- 2% window.

The scoop

The decision to move towards the low-power Bluetooth wireless protocol is key to the KeO Power’s success. Without it, the system is simply more expensive and less versatile than the upcoming Garmin Vector. With Bluetooth’s strength in the smartphone market and elsewhere in sports electronics, KeO Power users could actually have more and better head unit choices than Garmin users relatively soon.

The KeO Power is still more expensive than the Vector, though. Whether it is worth the extra cost remains to be seen, and will be largely dependent on the precision of the Vector as well as the quality of the pedal body itself. Garmin is using a body produced by Exustar, a brand without the caché and long-term reliability of Look. It is entirely possible that while the Vector’s electronics will be fantastic, the pedal itself will be the weak point.

Plus, in speaking with the other journalists here at Look’s launch, none have had a chance to get on the Vector yet, despite that fact that it will supposedly be available to the public in just a few months. Don’t be surprised if that date gets pushed back once again.

The entrance of pedal-based systems into the market is only a good thing for consumers. Usability and versatility are both drastically increased compared to anything currently on the market. If accuracy is truly as good as Rad Labor claims, then the SRM’s primary benefit becomes less potent. While prices are still high across the category, they are slowly declining and additional options can only hasten that process.

Tomorrow I’ll be visiting Look’s factory in Nevers, France. Check back for more.

Editor’s note: Look and Polar covered the costs associated with VeloNews.com’s attendance at the KeO Power launch in Europe.