On several occasions now, I have bought old boat trailers (and a few little box trailers), which are perfectly serviceable, but did not want to keep the primitive and often broken ball type wheel bearings. There is no bearing that will fit from a 20mm shaft to a (30305 part number bearing and stronger hub), metric taper roller bearing. Neither will the ball bearing fit the now standard taper roller hub. The old hubs being made of pressed steel and either buckled, rusty or normally both. My converter fits a 20mm stub and the new bearing part number 30305 with hub. It also saves having to change the suspension from Imperial to Metric, which has different holes sizes and would normally mean a new trailer, so huge savings from a little conversion.
30305 bearing size:
Outer Race Width: 15mm
Width: 18.25mm
Outside Dia: 62mm
Inside Dia: 25mm
I am happy to make more, but would only do so if I had a decent number to make, not just one set as the steel is too costly for one set. If you are interested, please let me know.