It appers to me that your buldging sidewalls are interfering with the belt. And that a wider rim would give you the stretch you need.
Also, I believe that on those wheels the inner bearing sets recessed inboard of the wheel’s lip.
The Rockstar Pro II XL has the bearing out flush with the inner lip of the rim.
I’ve just recently purchased two sets of Rockstar Pro II XL directly from MBS.
I have 25mm spacers built @Dinnye in route to me now:
Using this configuration still utilizes the standard 38mm of axle space (8mm bearing x 22mm spacer x 8mm bearing) as any standard wheel. Yet stretching the the hubs width out to 80mm.
And my rims are considerably more narrow the Dinnye’s.
