pictured is not the last version, i tried stuff and just put the battery closer to the front truck, better stability. This is the "test" setup, and, i have tested, i'm convinced.
I had troubles finding what product would be the best for me on the internet : was looking for belt drive for using orangatang wheels, sufficient range, and safety
i'm do downhill longboarding at a european competitive level so i just would not buy a flexy, flat, big board. I user an old Jet board, 9.5", 84/90a front and -5° 88/97 back
took only one slam because of a wet patch i did not see (helmet is MANDATORY whatever your skill)
did 280km, 70km/h downhill seems to be close to the limit of the trucks even on a big board, and my average speed on this is around 30, so 2minutes per kilometer. Super handy for commuting, super fun, you can have downhill like full grip runs almost anywhere, easy 45 km/h on the flat...
only thing i'm a little worried about are the belt, because i may be way more brutal with my board than most reviewer on the web and it tends to touch rocks and big cracks. I'll get bigger wheels as soon as one fails, will fix the issue.
Let me know if i can send you a clip or two, @maxime.moineau on instagram/youtube
And good work putting an insert for the back truck, few knows but... yeah i don't have any downhill setup without inserts or sphericals. Just better.
Would advise, but take it easy it goes fast enough to get hurt !
May do a review some day but the weather in France is not that good this season.