Hi Steve
Can you post a link to the site where you got your rims from please?

Take your wheel to a motorcycle shop and ask for a front inner tube to fit.
Don't tell them the diameter or they will tell you the don't have any.
Apparently motorcycle rims are measure differently or use different length inches but they do fit perfectly im using them.

just get 21" x 2.5" they are a tight fit but perfect for owe wheels

Thanks for the answers, if I have problems with punctures of my tube more regularly, I will certainly have a look in a motorcycle shop and see what they have to offer.

For the wheel damage, I didn't yet open up the wheels, so I only have pictures from the outside (both sides of one wheel):


You can see that the hub has shifted approx. 2 mm in the axial direction.
The next picture is from the previous time I had the same problem, unfortunately I did not take any pictures when I repaired it. Here you can see that after shifting in axial direction, the hub also shifted a bit in radial direction, resulting in a bigger gap in the outside wheel disc. (the broken weld that you see on the picture was a bad weld, I improved it already and now that part doesn't cause any problems anymore).


During the whole progress I only use polyester resin.