The reason I do this is to finance a part of the production cost (The €14 will probably not cover the cost for one piece )
The mount will be made of construction metal S235, lasered out of 4 & 15 mm sheets and finished with a white galvanization and comes in 2 parts attached togheter with M5 bolts.
Oh I didn’t write it will be lasered out of metalsheets 4 and 15mm. And yes on the round side because it is easy reachable, but I will change it to the flat side. Thanks for the feedback!
Put this together, with a metal prototype, bolt a motor on, and turn it on, with belts and pulleys and wheels, then bash the skateboard wheels-first into a concrete wall as hard as you can for 15 minutes.
If anything moves, it needs to be redesigned.
Because, in fact, that is exactly what happens while riding a skateboard.
there’s been other mounts like this where the hangar clamp is held using just set screws and even with a lot of torque and loctite it comes loose after a short while.
It seems like you have come a far way , but as others have said, i highly suggest you to get at least one made and tested before you start selling them.
Good luck!
You cant change the belt tension, you really should take attention on that.
About the set screw, some people don’t understand physics I guess, because of the form of the caliber truck, your design is even better than putting the screw on the opposite side, because now when you pot tension on the screw, you will have a 3 point fixing (the bottom of the screw, and the two opposite corners). It is a good design, just make sure to use a strong and big enough screw
sorry 1 more thing, the more they say it’s impossible, the more you can prove the’re not right
(The €14 will probably not cover the cost for one piece 
)
, but as others have said, i highly suggest you to get at least one made and tested before you start selling them.
Good luck!