Hi, I have two electric bikes both weighing about 20kg without the battery. What is the best way to transport them. I have a towbar but it will be used for caravan. Was thinking about either roof bars or a saris bones 3. The saris has a weight limit of about 45kg for 3 bikes so was thinking that 40kg with two bikes would still be within its limits. 20kg is a bit wobbly to lift onto roof sometimes. any comments much received.