There is a way to carry your 53 lb ebikes on the back of your trailer, though the Swagman Around the Spare Deluxe 2 Bike Rack for RV Bumpers # S80501 has a 35 lb per-bike capacity so it would not work.
Instead, you need a hitch designed to be used on the back of a trailer, the Curt # 13703 which will work on box frames, C-channel frames, or I-beam frames that are between 22" and 72" wide. For a bike rack you need the Swagman E-Spec # S94FR because it is rated for use behind a trailer and... view full answer...