[CR] Which dropouts on this unusual fixed-gear ??

http://www.flixxy.com/chinese-bicycle-acrobatics.htm

Given the aggregate age of the rider(s) is probably 200+, I hope this qualifies as an "on topic" video for the CR list ... :-) :-)

I noticed that the bike at the end had the largest dropouts I had ever seen, which is the technical real reason I am outing the images on the CR list ... :-) :-)

- Don Gillies
San Diego, CA, USA