You train with power on the road all winter, but once the trail conditions take a turn towards race season, you're left relying upon perceived exertion and heart rate zones for your training and racing. With PowerTap's G3 MTB Disc Hub, you'll finally be able to utilize power analysis off of the road.
Whereas the road versions of the G3 hub are lauded for their relatively small (57mm) diameter, PowerTap knew that an off-road version, required more strength and durability to withstand the hits and torque of trail riding. Accordingly, you'll find that this G3 iteration draws on more of the traditional G2 PRO design. However, as stated, this is because the G3 MTB hub is specifically designed for mountain bikes with disc brakes. Along these lines, the hub features a 74mm diameter and a 15mm alloy axle. And, as a result, the hub achieves an incredible stiffness-to-weight ratio. The total weight of the hub is around 680 grams, which is about 350 grams heavier than the current road G3. But, taking into account that the listed weight also includes the 160mm rotor, 680grams is pretty negligible.
The G3 design features PowerTap's "torque tube" design, which relies on eight strain gauges. The eight strain gauges for the powermeter are a system of sensors that detect any resistance and then vary their output when experiencing applied force. The next step is for the strain gauges to convert this data into electrical resistance, making it capable of being measured. The refinements to the system provide stellar results. In fact, it yields measurements within +/-1.5%. And as with the most recent iterations of the G3, PowerTap built the electronics into the end cap. So, by having the "brains" of the operation at the end cap, you're now able to easily remove the electronics for service without swapping out the entire wheel. Another improvement that comes with this change is that a single CR2032 watch battery powers the transmitter. These batteries are simple to source, and last for approximately 300 hours of riding.
As is the standard, the G3 is equipped with an ANT+ wireless transmitter that sends power, torque, speed, and virtual cadence data to either PowerTap's Joule or any computer unit that translates ANT+ (note that it doesn't work with Yellow CPUs.) The G3 is capable of storing up to 15 hours of data in one-second gathering intervals, and up to 30 hours of data in two-second gathering intervals.
The PowerTap G3 MTB Disc Hub is available in the color Black and with
a 32-hole spoke drilling. The spoke hole is 2.5mm, so it's compatible
with conventional double-butted, and most oval-bladed, spokes. The
flange diameter is 74mm on the non-drive side, and it's 70mm on the
drive side. Also, the hub center-to-flange measurement is 31.3mm for the
non-drive side and 18.5mm for the drive side. It's also compatible with
standard SRAM/Shimano hub bodies. 160mm rotor is included.
- Increased stiffness & durability
- Standard disc brake compatible
- Accurate to within +/-1.5%
- CR2032 watch battery
- Power, torque, speed, & virtual cadence data