Hi everybody,
This is what I have achieved with some unorthodox and hair raising methods. First, I sanded down the protruding and curious seam on the outer edge of the rim part. This brought its diameter closer to the tire's gap.
Then I carefully widened just a bit with Dremel the gap of the tire and checked constantly that I didn't sand too much. Well, after these measures the outer rim part sits nicely in the tire. I'm surprised and relieved. I just wonder why Heller haven't corrected this obvious error!
Cheers,
Einar
In the right hand wheel you can see the erroneous rim attachment. On the left there is the outcome after I had sanded down the rim part and widened the tire gap.