My BMW is not offered with a roof rack or towing hitch option which precludes most available bike carrying systems. The body panels are made of carbon fiber reinforced plastic which contributes to energy efficiency but does not offer any structural strength. For some time now I have been working on a design for a bicycle carrier which does not attach to the body. I fashioned a system that employs two industrial strength suction clamps and some custom brackets I printed at work to secure the bike’s handlebars to the rear window while the seat rests against the rear of the car. Gravity holds the bike in the brackets and a safety strap provides a measure of insurance if something lets go. Followers of this blog may recall that the safety strap prevented a disaster when one of my prototype plywood brackets delaminated during a test drive. The same was true today when one of the suction cups popped off when I hit a big pothole. It has been fun working on this project, but I am officially abandoning this design concept. The leverage provided by the seat as a fulcrum translates every bump in the road into a huge force acting on the suction cups and brackets. I will either come up with a different design approach or use my Audi when I need to transport my bike.