looks like its another 2-piece bmx crank. i saw these before and wanted more info on them.
Well, the story goes that Grove came up with the design in the 70s when he was designing for Titron, which indeed made BMX parts. The concept was copied and modified by Roger Durham for his Bullseye cranks. Grove sold his version for mtn bike in the early 90s and now is maybe going to start making them again.
I still have original matching hot rods on my Grove Assault. It still sees occasional duty. I have replaced bearings over the years, but the cups are relatively soft and locating bearings again seems like a project. But... If you can just use an XT external bearing setup...? Is that what Grove intends? Replacement "collars" for spacing?