Hello Sebastian,
sorry to hear that, do you mean the bearings Strida part nr. 100-03 and 100-04?
(Please refer to the “exploded drawing 5.0” at page 14 of the Strida manual
Strida manual.pdf)
The changing of these bearings is not really difficult, but special tools are needed
(at least a slide hammer and a bearing extractor, mentioned already here and there.)
Do you have any pics of the damage?