Check the wheelbase of your bike. If it's very long, you might want something from Buzzrack. Just search the forum. There's a bunch of people that have already discussed this topic in depth
+1 Buzzrack BUZZ RACK Eazzy 3
Cheap, sturdy, foldable. 60kg max load. I re-drilled the locating holes so the folding posts fitted the bikes better without fouling the motors. Effectively a custom fit for my 2 bikes so they fit perfectly every time.