A common topic on RV forums is how to transport bicycles. Let's face it, bikes are not the most space efficient gadgets, but make a great addition to your camping/traveling. DW and I can put regular bikes in the back of our Toyota FJ, or the storage compartment of our 6501 Vibe trailer, but dang little else in either. The Vibe has no bumper, and the frame is awfully light by design, so adding a substantial bumper seemed unwise, and I have reservations about leaving bikes out in the weather. We found with a nice solution with these:
Amazon.com : Columba 26" Folding Bike w. Shimano 18 Speed Yellow (SP26S_YLW) : Folding Bicycles : Sports & Outdoors
A little pricey, but very space saving. Adjustments provide proper sizing from DW (5'2" / 110lbs) to myself (5'10" / 160 lbs). Max weight capacity is listed @ 200 lbs.