Yishun MTB Graphene rims

[numberzero]

Hello i would like to share my mixed experience with the yishun MTB graphene rims i use and used...

Last year i bought a ASD933XC-GP to rebuild a front wheel. In hand quality is very good, wheel is easy to build.
Compared to my previous EIE A29C25D22, yishun rim is ligther (20 grams), wider 27 internal vs 25. Yishun's seems a bit less rigid and more comfortable too, my feeling is a bit more tolerant wheel.
I had no problem with this front wheel, using it for more than 1 year now.

This summer i decided to rebuild the rear with the same rim.
Quality was the same, very good, same ease to buid the wheel.

I rode it around 500km when i discovered a bad crack between 2 holes. Without any damage on sidewalls which could be sign of pinching. Wheel was still true anyway. No damage on spokes...
Moreover i'm always using noodle to prevent rim to be hit.
Impossible to say when this happens or how long i rode with that.

According to yishun, it's due to a crash, not a rim failure and they only offer me 20% discount for a replacement...
At the moment i'm very dissapointed with the situation and the customer service. Let see how it end... to be continued...

These ASD933XC-GP rims are said to be for XC, they are not crazy light sub300g and i'm a light rider too. If someone has an idea of what could happen? Pictures of the damaged area attached.

[TidyDinosaur]

I'm no expert, but I get why they say this was caused by a crash or by a large rock strike... This seems to be impact damage...

[numberzero]

Yes it seems like an impact. But so precise and powerfull it makes the rim exploded like and didn't affect the tire, the spokes or the nipples, without i notice anything and wheel stay true? I can't believe it... what is the chance of this happening 0,00001%?

What afraid me is that Yishun seems to know very few about cycling, they discover what is a pepi noodle or saying me i need to run 30psi (2bar) on XC...

[numberzero]

Now i have two rims naked and can compare them.

One old EIE A29C25D22, weighed at 356g, 30 wide, 25 internal, 22 height
The ASD933XC-GP weighed at 343g, 33 wide, 28 int, 24,5 height

Despite a higher profile the ASD is much more easy to flex verticaly than the EIE (rim on ground i press on top and feel the result). I understand why the feeling on the terrain is a wheel being more tolerant, more comfortable, the rim is probably less rigid in other directions too. Is it because of the lowest weight with biggest dimensions?

That also confirms the feeling i had with the EIE rims which was more influenced by the tire pressure.

By the way yishun/lightcarbon says graphene prepreg is stronger and more rigid, probably with heavier rim but that was not my feeling.
None of the EIE or ASD was bad or best, they just gives different wheels.

[Pedaldancer]

Yes it seems like an impact. But so precise and powerfull it makes the rim exploded like and didn't affect the tire, the spokes or the nipples, without i notice anything and wheel stay true? I can't believe it... what is the chance of this happening 0,00001%?

What afraid me is that Yishun seems to know very few about cycling, they discover what is a pepi noodle or saying me i need to run 30psi (2bar) on XC...

A rheynolds rim in the basement looks similar. Also this wheel stayed in shape, nothing wrong with the tire or spoke. It just got visible due to bike check before selling it. The rim stayed here, as it is damaged.

I would say that gives the impression that even with this crack the remaining material can currently hold against the spoke tension.
I would think hitting a rock or stone could create this kind of impact. It's bad luck though.