The attachment contains the reply I received from Ltwoo's official support regarding the waterproof performance of the EGR. The main point stated in the response is that the waterproofing of the EGR has been improved compared to earlier versions (at least according to their official statement).

... Do we have any idea where the ingress is? ...

Unfortunately, I don't have the physical EGR item with me, and my friends are also unaware of the specific areas where potential gaps may exist. All repairs are handled by Ltwoo officially.

However, I have a suggestion that may not be fully matured. Perhaps applying some waterproof spray meant for outdoor clothing on the outer layer of the rear derailleur could be helpful?

I will try to ask them. Usually, I can contact them directly through platforms like Taobao or WeChat, without the need for emails. However, based on the feedback I received from secondary distributors in the past, the new versions of the EGR did not improve the waterproofing performance. In special cases, it is necessary to disassemble the rear derailleur and manually apply some waterproof sealant. But such an operation may result in the loss of warranty eligibility.

Based on the experiences of my friends, they had to wait until the rear derailleur got water inside and caused issues before contacting Ltwoo for repairs or part replacements (mainly due to water ingress in the rear derailleur). This process can be frustrating, and this issue may not necessarily occur in every kit. I am inclined to believe it could be a quality control problem. Moreover, purchasing Ltwoo from outside China would incur higher post-purchase costs, both in terms of money and time.

However, there have been some software improvements for the EGR, such as enhanced logic for situations like stationary shifting and accidental button presses. As for hardware improvements, there is currently no information available.

China does have similar forums, but we are not exactly like BBS forums. We are more like Reddit, with channels categorized based on discussion topics, and the discussions tend to be more basic. For more specialized discussions, we usually rely on WeChat group chats, which are more closed-off but allow for deeper conversations.

Interesting (and unfortunate) news on the water resistance. Do we have any idea where the ingress is? I was planning on using dielectric grease in the ports to help ensure that isn't the ingress. But I wouldn't want to have to rip apart a new one to coat it with that or conformal coating.

At the back of my mind I still worry that I am subjecting the rear rim to bad stresses via the radially laced spokes on the disc-side.

That should not be the case, provided that your rim is drilled for a 2:1 pattern? If your rim has the usual drilling with alternating holes angled left and right then it won't be compatible with 2:1 lacing, because that obviously requires 2 holes angled to the DS followed by 1 to the NDS. But I'm assuming you know that.

Something I noticed is that on the rear wheel, I have pretty much dead-even spoke tension across both sides. In my mind this seems desirable, no?

Yes. That's exactly what you want. And 2:1 lacing was invented exactly for this purpose. On a traditional 2crossed rim brake rear wheel with let's say 12spokes on each side, you'd get as little as 50% or less of the spoke tension on the NDS compared to the DS. Particularly with aluminium rims where usually the max spoke tension must not exceed about 1200N, you'll get less than 600N on the NDS. That's low enough that the spokles might detension themselves over time when the wheel hits potholes etc. With (high quality) carbon rims the spoke tension can be higher. I've built wheels with spoke tension in the 1500N range. That makes detensioning less of an issue. With carbon spokes the tension is even higher because those are not as elastic as steel spokes so they need to be tightened to crazy high tensions.

Hey Sebastian, thanks for the notes and kind feedback!

If this really is your first ever wheelbuild then you chose something with quite the steep learning curve

I've rebuilt 2 wheels in the past to replace carbon rims broken in racing incidents. Not sure if that counts! Definitely was my first time speccing out a full build and calculating spoke lengths, I think half the fun was playing around with spreadsheets and fantasizing about different builds.

I definitely agree with you that the decisions to go for 21-spokes and internal nipples are the most disagreeable and impractical choices I made. I've already had to strip my rear wheel to re-tension and true after the first 100k, and the front wheel will be next soon. No doubt a PITA, one I knowingly signed up for. I appreciate your notes on spoke hole sizes as well, good to hear a more experienced perspective on this idea.

I also appreciate your notes on the 2:1 lacing;
The decision to go for the 21-spoke build felt like a risk. At the back of my mind I still worry that I am subjecting the rear rim to bad stresses via the radially laced spokes on the disc-side. Will it be worth the 29 grams, and indeterminable, marginal CdA that I saved? Only time will tell, I suppose.

Ever since disc brakes, both side's spokes had to move inboard and the difference in spoke angle and tension isn't as bad as it used to be. So the advantage of 2:1 isn't really as big as it used to be.

Something I noticed is that on the rear wheel, I have pretty much dead-even spoke tension across both sides. In my mind this seems desirable, no? Obviously since I'm new to this, I could be overlooking something or overstating the importance of this. On that note, something I do not like about these hubs is that on the front wheel, the radially-laced side achieve significantly higher tension than the crossed spokes. The idea that a minority of the spokes on a wheel are at a higher tension than the majority does not sit well with me, especially on a design that is supposed to "balance" spoke tensions. In retrospect, I agree that an asymmetric rim is probably the better way to do it, the asymmetric rims on my ICAN Aero 35s does a much better job balancing spoke tensions on the front wheel.

Anyways, I definitely learned a lot from the experience of building these wheels. I think next I'll build up some gravel wheels, and stick to a more traditional build

Does anyone know of a high quality silicone grip similar to an ESI Extra Chunky?

I'm using ones from ODI, was like less than $5 on sale, and good quality (durability still to be checked)
but they seem more like the chunky ESI's, not 'extra'