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
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