Hi everyone,
Just wanted to update, even though it's been over 6 months since I interacted with Magene's customer service. The take-home message is I'm fed up with Magene's customer service and engineering. I've come to the conclusion that the QED crankset (in particular, the integrated chainring) is badly engineered (as I explain later), and there is absolutely no recourse via customer service and/or aftermarket options. Seriously don't buy these things, (either version with the integrated chainrings--power meter or not) they suck and are irredeemable in every way.
Their marketing department reached out in June and promised me a new chainring. They also begged me to delete this thread (see attachment) because it made them look bad. As appalling as I found their plea, I didn't want to share it because I wanted to give them the benefit of the doubt, in case the chainring actually solved the problem (spoiler alert: it didn't). The new chainring came in a partially-crushed box, was bent out-of-the-box, and it only worsened over time. In the ensuing months I had thought about making an extensive Hambini-style takedown/reaming video, and just didn't get around to it since I'm busy trying to graduate from my PhD program. But today I finally replaced the damn thing and found enough anger in my heart to make this post. I think the lesson here is that you should exercise caution when buying from Magene. Their fancy marketing does not set them apart, they are just like every other Chinese brand. They seem to make some decent products (i.e. the PES) but if you get a dud product from them you are well-and-truly fucked.
So: what's wrong with it? Fundamentally, the chainring deviates from the centerline by around 0.5-0.9mm. This is enough deviation that the chain will hit the derailleur when you approach a gear on the end of your cassette, especially when sprinting. You can check my previous posts in this thread for videos. This problem really rears its ugly head with Shimano's derailleurs, which are exceptionally narrow. No amount of derailleur tuning has solved my problem. I've even resorted to trying to bend the rings back to place--to no avail. This problem seems to get worse over time, suggesting that this chainring is so weak and poorly designed it cannot handle the stresses of your average rider. (Like many people, I can briefly hit 1000W in a sprint). You can imagine how annoying must be in a sprint. I can't count how many times I think I have managed to get the derailleur tuning just right, only to hear it grinding away at the lightest suggestion of a sprint in my 12t. Sometimes I've even had it bend so much into the derailleur that it knocked the chain off.
Normally you could solve this issue by buying an after-market replacement chainring or spider. Well, it turns out the direct-mount engagement pattern is completely proprietary to Magene. Superficially, it resembles Shimano MTB or Cannondale's direct-mount standards, except it's like an inverse of Shimano MTB-DM. It's more similar to Cannondale's standard, except that instead of 2 long lobes on the spider, it has just 1. In any case, if you don't want to deal with Magene's stupid chainrings, you're fucked. These cranks are officially useless.
Oh, also, the issues with the power signal randomly dropping out that DC rainmaker found on the original P325CS cranksets seems to be still happening. Hooking up the chargers to the pods is fiddly, you have to contort the cables in orientations that are not natural for them to be in, and then hope you have aligned and supported them just right so the magnets will take. If you screw this up at all, the magnets fall off and you fail to charge. Another thing I don't like about the crankarm-mounted power meters is they stick out quite a lot. Like around 1cm. I get that this is an aero-weenie complaint, but theoretically this is a problem for aerodynamics--the crank arms turn out to be a pretty important area for optimization and having a pod sticking off of them undermines that.
Before I replaced my cranks, I had some shred of a reservation that maybe these issues were just because Shimano's front derailleur cages are so narrow. But after replacing them with a unit from Incolor, I can confidently say that it's Magene's fault.
Given that I have no way I have no idea what I'm going to do with them now. Maybe I'll give them away to someone with a bike that has a wider derailleur cage.
Let my $500 mistake be a warning to you. Don't trust Magene.