power2max NGeco SRAM MTB Power Meter

If I could give this 3.5 stars I would. I bought it for the one bike that I own that won’t accommodate anything larger than a 24mm BB spindle. So a Quarq was out because they’re all DUB now, and I’ve got nothing good to say about my limited experience with Stages. So I was glad to be able to put this on an old GXP XX1 crank I had. After about 3 months on this PM, my conclusion is that it is better than Stages, worse than Quarq. It is two-sided power, which I think is important for mountain biking in order to accurately track power. This has proven to be pretty reliable so far, as well.

For me, I’m not rating it five stars for a couple of reasons.

The frame I bought this for has non-boost spacing. If you have a non-boost frame you have to pay $50 extra for the right version. What does that $50 get you? A purpose-built spider with a little more offset for a non-boost chainline? Nope. For $50 you get a kind of cheesy looking stamped metal ring that mounts between the spider and your chainring to correct the chainline of the boost-spaced spider. It works, but it’s ugly to look down at, and there’s absolutely no way it should cost you $50 extra. It probably costs about 50 cents to produce.

Also–and this is hard to absolutely verify–I honestly think this PM reads low for really spiky efforts like mountain biking (which is of course what it’s made for). I know this assessment could be seen as an ego thing, but I say this because I have Quarq PMs on all of my other bikes, and they are all extremely consistent in the average and normalized power numbers they churn out. This PM consistently reads a bit lower on average power, and about 20w (about 8-10%) lower for NP on the same training rides. This isn’t a big issue for an hour-long ride, but if you’re doing a 4-6hr ride that 8-10% will really affect the accuracy of your TSS for that ride. Again, it’s hard to verify this absolutely because there’s no controlled environment. But with 3 months of riding and a bit of racing on the thing, I’m finding that I can consistently expect this discrepancy. I’m not sure what to attribute it to. Another reviewer notes some lag in the data readout, and I’ve noticed this as well (at least compared to a Quarq—it’s on par with Stages). I don’t know if that means that short bursts of power don’t get fully read and that translates into lower average and NP numbers over the course of the ride, or what. But as I said, for me it’s become a pretty unmistakable conclusion. I’ve learned to just factor it into my interpretation of ride data on this bike.

Having said all of this, I do have to acknowledge that this thing costs a little over half of what a Quarq Eagle PM costs, and I can live with its foibles at that price.