In the interest of safety, I must caution against taking risks with Fiamma bike racks. By taking risks, I refer to placing, for example, an extended wheelbase ebike into a channel designed for a safe working load of 15Kgs.
Although my rack is labelled as having an overall weight limit of something of the order of 65Kgs, the individual channels are limited to 15Kgs. Even without the battery, my Gazelle weighs way over 20Kgs but more importantly perhaps, vertical centre lines through the wheel hubs coincide with points slightly beyond the ends of the standard channels.
I choose not to carry my ebikes on my rack, preferring to house them in the garage, (large storage area at rear of motorhome, for the benefit of non-campers) where there is no risk of them detaching into following traffic. I have no hesitation in carrying my regular bikes on the rack, (c15Kgs each). The point I make about that extended wheelbase, even if longer channels are fitted, is that the rack fulcrum points are a long way inboard of the bike extremities and I have suffered one damaged channel due to nothing other than the normal up and down forces.
The weight factor is a consideration not only for the structural integrity of the rack. It mustn't be forgotten that the rack isn't actually bolted on to anything particularly substantial at the rear of most motorhomes. Quite simply, Fiamma racks were not designed with bikes of 25-30 Kgs in mind.
Indalo