The need for power isn’t just a roadie thing. With more and more mountain bike racers looking to wattage for training purposes, the off road power meter market is experiencing a similar evolution as road. For Powertap, that means taking their already popular mountain bike hub based powermeter and dropping a big chunk of weight. Compatible with both quick release and thru axles dropouts, the New Powertap G3 rear disc hub clocks in at more than 30% lighter than the previous model…


hubs_g3_disc_142mm_thru_side hubs_g3_disc_135mm


Having access to power is a great tool for racers but not if it comes with a big weight penalty. That’s exactly why PowerTap redesigned their hub to  remove an impressive 180g. Now checking in at 350g for the hub, PowerTap also provides the weight of the 160mm brake rotor at 150g. Due to the design of the hub the G3 uses a proprietary brake rotor with a larger bolt circle that is included with each hub.

Offered in 24 or 28h bodies, each hub is shipped with end caps for both 142 x 12 and 135mm quick release dropouts. Using a straight pull, stacked lacing hub flange design, the resulting build has been tuned to be as stiff and efficient as possible. Equipped with a 6 pawl freehub mechanism, hubs are available with either Shimano/SRAM 10/11 or SRAM XD bodies. PowerTap G3 hubs include both ANT+ or Bluetooth SMART connectivity and offer a 1.5% accuracy rating. Sold with a 2 year warranty, the G3 retails for $989.99.


  1. Have an unused one from the last generation sitting in the box. The 160mm rotor just doesn’t do it for CX, which is really who cares about their power anyway. Come up with a 140 mm solution and you’re almost there (though dropping the massive aluminum 8 bolt carrier to the rotor is a good start)

  2. @Bill,
    why no straight pull for off-road? You don’t like being able to replace a spoke without removing the cassette and rotor? Or is it the fact that they’re less prone to breaking in the first place? Or is it that they don’t have to be interlaced, so you don’t get that soothing metallic twig sound when climbing in a very low gear?

  3. @greg, not exactly … Ding sounds are from the unreleased tension, replacing 2-3 spoke(s) is waste of time when you’re on 36/32 spokes compared to 24/28. OTOH with straight pull system the hub itself is prone to breaking, and for the final there are two types of spokes – those who will break and already broken.

    Also alu frewheel again? You know what happens with standard cassettes, or with those having alu spider only first 3-4 cogs.

  4. Greg, they are straight pull not radial, and as such are probably the most reliable method you can build a wheel.
    The spokes pull opposite each other, effectively canceling most forces on the hub.
    All of my wheels are like this, both road and MTB.
    The only bike I have with conventional flanges is my commuter, but is has 32 spokes.

    As to a proprietary disc, no thanks.

  5. @Darryl, the disc has to be special because they need to do the best they can to eliminate heat transfer from the disc to the hub itself where the heat would cause thermal expansion of the strain gauges, giving false power readings. From what I can tell, the disc is the same that came with the first gen MTB hub and from my experience, it was a very durable disc. However, due to the weight, I eventually dropped it in favor of a Stages PM.

  6. Had a co-worker nearly cut through the aluminum freehub body on his previous PowerTap using it off road. He puts down some Joules.

  7. I don’t care why they have to, but I don’t want to pony up for special discs that may or may not be available.
    Especially if they are some squeally Avid type things.

  8. So, heavier than a Stages, tied into using their rotor, one wheel and more expensive than a Stages when built into a wheel. Then couple it with dodgy bearings. Think I’ll stick with my XT Stages cheers.

  9. @schmiken – not to mention it actually measures power (well, that may be arguable but at least it doesn’t guestimate by doubling left leg)

    In the interest of being fair and all.

  10. @elvis if the Stages is good enough for Team Sky then Im pretty sure its good enough for us Strava lovers. 😉

    Ive a powertap. Good product and as consistent as my 5 Stages on my different bikes but I would not buy another one cos there is no need too. I can get a cheaper, lighter product that doesnt even require servicing.

    Ive had a power tap die from a rainy day too. None of my Stages have died from wet weather. Im always sure to put the caps back on properly and also put in a bit of White Lightening Cyrstal grease.

    In 3 years time I can’t see many of the current power meter companies still in business due to how much Stages is dominating sales internationally now.

  11. I’ve never had a power tap product that was reliable. I’ll never buy another. Especially when their are so many other options.

  12. @durianrider ” if the Stages is good enough for Team Sky then Im pretty sure its good enough for us Strava lovers. ”

    this will probably come across terribly and I don’t mean to be an ass but it’s this sort of “logic” that explains why they’re still in business. If this sort of estimate is “good enough” for you I’d question your reason for having a power guestimator in the first place.

    maybe ask Dr. Coggan his opinion on what value a stages paperweight adds to your training. the information is out there. It’s your choice to ignore it.

  13. How useful is power data for mountain biking anyway? It makes sense that it would be useful to know, but it seems like it would be challenging to get a “clean” read on how much power you are putting down given the variability of pedal force thanks to roots, rocks, loose dirt etc. I can totally see how power would be useful to know to quantify fitness when doing theoretical hill climbs on a trainer though.

    I have a powertap with ALU freehub on my road bike and have damaged it. If it becomes unserviceable I’ll buy a steel one. I suppose they spec it to save some weight but for training use it is unfortunate. It has otherwise been reliable across 5k miles though I try to avoid riding in the rain. My next powermeter will be crank based though so that I can swap wheels back and forth without losing power data.

  14. They lost me at the proprietary rotor…and not only is Stages good enough for Team Sky, it is also good enough for MTBiker’s like Ralph Naeff, Luna Pro Team, Scott-3Roxx Team, Cannondale Factory Racing and a roadie named Cavendish or something…

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