I tried to find decent 28x8 mm skate bearings the other day but I couldn’t really see any. I found a couple but the widths were way off and I wasn’t sure they could be made to work. The only ones I noticed were similar didn’t have any seals so they’d wear out pretty fast.
I may well have been looking in the wrong places though. Certainly none of the skate shops had them, but there are other places I tried too.
I DID try trampa because I knew they had some kind of converter, but I didn’t notice they did one specifically for their wheels. Might be something to keep in mind for the future (if I’m unable to find a 28x8mm bearing!)
Someone did send me a picture of a 10mm bearing with some kind of spacer inside it that made it fit to 8mm, but I couldn’t find where to buy those kinds of adapters. (It was just a metal sleeve, not the trampa one)