ok...i got some spare parts...so what i do what the dynamo?i cracked one open. To my amazement...there are NO bearings inside. No wonder, this unit heats up badly. The shaft is only lubed with some grease, which will dry out in no time and cause even more friction/heat.

The only benefit of using a sidewall dynamo is the ability to engage when you need to. Question to all, do the more expensive bottle units have bearings inside? I hope so...