When the Lemond Revolution trainer was first introduced, there was a lot of talk about the benefits of no longer needing a rear wheel for your bike when it was on the trainer. There was one big negative though, without the rear wheel that meant rear wheel mounted computers or Powertap hubs couldn’t be used. For cyclists that are using wattage based training that was a deal breaker. Yes, for a while Lemond did offer the Power Pilot computer system, but it didn’t really seem to catch on with its $439 price tag. Enter the Lemond WattBox. Not only is the WattBox almost half the price of the Power Pilot at $249, but the WattBox calculates the power in trainer mounted box, instead of the head unit like the Power Pilot. That allows you to use your favorite ANT+ compatible head unit or ANT+ certified smartphone apps.
Crank up the power next.
As mentioned in our report from Interbike, the nice thing about the WattBox is that is it compatible with both the new 1.1 Lemond Revolution trainers, but also the original 1.0 models, so as not to leave anyone out. Mounted on top of the Revolution trainer, inside the WattBox is an internal processor that will take temperature, humidity, altitude, and RPM into consideration, and outputs an accurate power reading. Lemond states that the one constant is the amount of air that each blade of the flywheel displaces. While the volume of the air will never chance in a controlled environment, the density of the air will change which is why the temperature, humidity, and altitude are considered.
“The new LeMond WattBox uses several sensors to accurately determine the power being generated by the rider,” said LeMond designer Evan Solida. “The resulting data is then transmitted via ANT+ to any compatible head-unit where the watts will be displayed.
“First, the aerodynamic resistance is determined by measuring the speed of the flywheel and also involves a function that measures air density,” Solida added. “Mechanical losses are also considered as the belt used to spin the flywheel has a mild temperature dependence and there is a slight bit of bearing resistance. Finally, mechanical resistance from the drive-train is entered into the equation.”
Riders wanting cadence can add any ANT+ cadence sensor that is recognized by their head unit. While cadence isn’t required for the WattBox, it will result in more accurate power measurement and will keep the unit from showing power when coasting.
WattBoxes are available through the Lemond website for $249 for the trainer mounted sensor. Head units, cadence sensors, and trainer sold separately.