My wheelset finally arrived. Peter asked me to post a review which I'll gladly do! The wheelset uses D50CU-28 rims with the in-house hubs and CX ray style spokes. As a specialty I ordered the variant without nipple holes. This makes for a painless and more reliable tubeless setup for just a little bit extra cost. Wheelset came in slightly lighter than expected at around 1330 g. So far I've put on GP5000 S TR tires which was indeed painless to do, it worked much better than on my older rims for some reason. No tricks needed, just put on the tires, a bit of pumping, done. I'm still waiting for other parts for my bike build, so I haven't used them yet, but from what I can see, everything is solid and they run perfectly true, too. Freehub sound at first seemed extremely loud, but with tire and cassette installed, it now sounds a bit muffled and much better.
Edit: by the way, I also ordered a spare freehub (because I've always had bad luck with freehub bodies for some reason). This was very reasonably priced, I think at 25 USD.
Edit2: now I see D50CU-28 is now available in T1100 too! Damn those rims are light! Maybe I should have waited a bit lol! I'm still satisfied since my wheelset is really good value for money though, got the basic T800 variant of the rims. The T1100 rims are probably quite a bit more expensive.
