Garmin Vector Pedals
While it took a number of false starts to get the Garmin Vector Pedals to market, their arrival last August was worth the wait. Among the biggest benefits of the Vector over other options is transferability. Swapping pedals from one bike to another is more efficient and easier than switching a crankset. While swapping out a wheel is equally as easy for those who train with hub-based power such as Power Tap, riders are forced either to use a single wheel for both training and racing, or must buy two wheels with hubs. With the Vector simply change over the pedals and pods.
The Vector system measures the force applied to each pedal through sensors installed in the pedal spindle and in the pod which contains an accelerometer (for cadence). This is combined with the distance the crank travels to calculate power in watts. Traditional crank-based power meters measure the force transferred from the crank to the chainring via multiple gauges along that connection. The force (or torque) is then multiplied by angular velocity (the speed at which the crank arm is moving). Pedal-based power does effectively the same thing, but measures that calculation (torque multiplied by angular velocity) at the pedal. With two pedals, Vector measures total power output, but also output from each leg individually and in real time. This has the potential to quantify data more precisely. Exactly how this could impact rider efficiency in terms of bike fit and training programs is not yet fully understood, but could make a big impact on how we ride. Vector is not the first pedal-based system nor is it the first to offer separate left to right measurement, but its accuracy and practicality is exceptional.
Vector is compatible with any ant+ head unit as well as the Garmin Edge series and the Forerunner 910XT. While the ant+ will show current power, using the pedals with Garmin’s head units offers infinitely more functionality including the ability to sync to your smart phone for gps tracking, allowing others to follow your rides.
The Inside Scoop
There are two essential bits of information about the Vector Pedals that Garmin could communicate more clearly to first-time users. The first is the need to purchase a torque wrench to install the pedals (though a regular pedal wrench is fine for removal). Precisely 25 pounds of torque is needed to ensure the pedal sensors will work. It would be great if the torque wrench was sold with the pedals. Garmin could also include an inexpensive adapter (called the crowfoot) to go on the end of the torque wrench for the tight space between pedal and chainring.
The second crucial piece of information is that you must update Garmin firmware for the equipment to work accurately. This can be done by registering the product on Garmin’s website. You can then take advantage of the ant+ usb stick that comes with the pedals.
Pedal installation is straightforward. They come labelled left and right and must be attached to the pedal pods – the communication centres running information to the head unit through ant+. The pods contain the batteries (one CR2032 per pod) and, unlike the pedals, aren’t left and right specific as they are designed to be easily replaceable. It’s imperative that a gap is maintained between the pedal pod and the crank arm, so installing two washers on the outside of the crank arm is necessary to ensure there’s no movement.
The pedal pods need to be positioned so they never hit the ground. Each pod must point straight down when the crank-arm is horizontal.
The Garmin head units will prompt riders through calibration and a few easy steps to follow. Do the manual calibration unclipped and be sure to be 20 m or more away from other bikes equipped with power sensors, as the Vector pedals are highly sensitive. Also, be sure to backpedal eight times a few seconds into your ride to ensure accurate data. Once this step is completed, your Garmin will indicate that calibration is complete and your data will show up on the head unit. Vector’s long battery life (175 hours) means you’ll get in a lot of miles before needing to change them, and while you’re out there, you’ll be able to chase higher and higher watts with ease and confidence.–