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Messages - brain

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Road Bike Frames, Wheels & Components / Re: XM Carbon Speed Race Frame - The wish list
« on: September 21, 2025, 04:13:25 PM »
Quote from: PeterXu on September 20, 2025, 12:51:25 AM
We would get our US trademark approved soon, hopefully mid-Oct. Then we would arrange UCI approved stuff on our wheels and frameset.
That is great information! I'm in the market for a new race frame, and due to race regulations, it absolutely has to be on the UCI approved list.
For those who have more knowledge than me, what is the usual timeline for a manufacturer to get a frame approved by the UCI? I've heard it can be a long process, but I'm trying to get a more concrete idea.

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Road Bike Frames, Wheels & Components / Re: Xiamen Carbon Speed 2025 new carbon crankset
« on: September 18, 2025, 03:52:52 PM »
Quote from: toxin on September 13, 2025, 11:46:35 AM
Because they both come from the same factory.
Is that an assumption or something that's been confirmed? :o

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Road Bike Frames, Wheels & Components / Re: Xiamen Carbon Speed 2025 new carbon crankset
« on: September 13, 2025, 07:06:04 AM »
Quote from: Tines on September 13, 2025, 06:28:25 AM
If the chainrings are not completely true there’s always a certain chainring orientation where there will be good shifting and otherwise nothing happens or the chain get dropped off.
I agree, this is far from an ideal situation. My "fix" of adjusting the front derailleur has made it somewhat rideable, but it's a frustrating compromise and not a long-term solution. I'm already looking into a replacement set of chainrings.

I'm also wondering why the chainrings look identical to those sold under the Leese brand on AliExpress.

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Road Bike Frames, Wheels & Components / Re: Xiamen Carbon Speed 2025 new carbon crankset
« on: September 13, 2025, 05:37:28 AM »
Hey everyone,
last year I was happy with a wheelset from XMCS, so I was excited to try their new carbon crankset. I bought the 165mm crankset with a titanium spindle, a carbon spider, and 52x36 chainrings and installed it on August 15th.

During the install, I immediately ran into a major issue: the chainrings aren't perfectly straight. They have a noticeable wobble, no matter how I mount them (see also
Quote from: Tines on August 31, 2025, 07:27:42 AM
Had some challenges setting setting the front derailleur up.
). This made proper alignment extremely difficult and prevented me from following the standard Shimano setup procedure for the front derailleur. I documented the issues in some videos: https://www.youtube.com/playlist?list=PLpOdLtd9--n6iJWOi2Rnggwd_eTDubUag

I was able to get around the problem by setting up the derailleur so the chainrings wouldn't touch it while I was pedaling, but this is a major hassle. There's only a tiny sweet spot for the adjustment, making the setup process a huge pain.

I reached out to Peter at XMCS directly to report the issue. He advised me to discuss it here on the forums. So, here I am.

To figure out what was wrong, I tested the crankset with a set of Rotor chainrings. The wobble disappeared. This confirmed that the crankset itself and the spider are fine; the issue is with the chainrings themselves.

The chainrings feels like a "beta test" product. I expected much higher quality. If you're considering buying this crankset with the chainrings, I'd advise caution. You might end up with the same frustrating experience I've had.

I hope this helps!

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Component Deals & Selection / Re: Magene Heart rate Monitor (H303 and H603)
« on: August 20, 2025, 04:54:57 PM »
Hey everyone,
I’m a fan of Magene products and when I read about the release of the H613 I had to get one. However, I've been a Polar H10 user for a while now—it's been my trusty heart rate monitor for my bike rides. I dodged my previous Magene heart rate monitors due to connection issues when training indoors and connecting to several devices simultaneously.
After @cramy’s post, I decided to get my hands on the new Magene H613 and wanted to see how this more budget-friendly option would compare to the "gold standard." I put them both through a workout today, and here's my quick take.

First Impressions & Design
  • The Magene H613 is so light. The sensor unit itself is incredibly small. light and low-profile, which makes it feel very unobtrusive when you're wearing it. However, I never felt uncomfortable when using a heart rate strap. They've also clearly improved the strap design with anti-slip silicone dots, and it feels much more comfortable. It's a huge step up from other Magene HR monitors I've used.
  • One key difference regarding the straps is the locking mechanism. The Polar H10 has a very simple but secure snap-together clasp that’s easy to use. The Magene's is good, and a definite proven solution, but it just doesn't feel quite as good and easy to use as the Polar's. This is a minor point, but for something you'll be putting on and taking off constantly, it's a small edge the Polar has.

Accuracy Test
  • This was the main task for me. I ran both monitors simultaneously, with the H10 connected to my cycling computer and the H613 connected to my phone's training app (MyWhoosh).
  • I ran some analyses in R, using Mike L. Smith’S FITfileR package (https://msmith.de/FITfileR/articles/FITfileR.html):

  • As you can see, during my 58min ride, both monitors were virtually identical. The heart rate readings matched closely. The maximum difference was a heart rate difference of 10 for literally one second. Most of the readings matched almost beat-for-beat. Also, for high intensity intervals, the Magene H613 was right there with the Polar H10. It responded quickly to spikes and drops in heart rate and didn't show any erratic readings. I was genuinely impressed—the Magene's accuracy is on par with the Polar H10.

My Verdict
The Magene H613 is a serious contender to the Polar H10. It offers the comparable accuracy as the H10. It also has extra features—like the rechargeable battery and 3-channel Bluetooth. The improvements they've made to the strap also make it much more comfortable than previous Magene models. Even if the longevity of the H613 still needs to be tested, I do think that when you factor in the much lower price, it's a no-brainer for most people.
Will it replace my H10 Polar? After this test, the Polar H10 will still be my go-to unit. I've used it for so long and trust it implicitly. However, the Magene has proven to be an excellent alternative. In case my H10's battery dies unexpectedly or the unit fails for any reason, the Magene will surely step in as a more than capable backup.


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