This iconic frame design (said to have been invented by Richard Cunningham) started to appear around 1988, and lasted well into the mid 90s, the elevated chain stay (or e-stay) gained a cult following, but never came close to replacing the classic double-triangle frame design.
E-stay frames allowed for greater clearance for the rear wheel, a shorter wheel-base for better climbing and manoeuvrability, elimination of chain-slap, and the ability to remove a chain without breaking it.
For many, these advantages outweighed the downsides, which included additional weight, and some extra lateral flexibility and weakness in the bottom bracket area.
A fair few e-stay frames eventually snapped or cracked after sustained but not excessive use – particularly those built from aluminium or titanium. It’s still possible to find e-stay frames for sale on ebay or retrobikes, mostly in steel, but with the odd uncracked aluminium or titanium specimen.
The rise in popularity of 29″ and 650b wheeled mountain bikes has rekindled interest in elevated chain stays, as a way to have a shorter wheel-base when using big wheels: There are already e-stay 29er prototypes going around (photo below).
It would be rather ironic if a modern innovation like large wheels were to now lead mountain bikers back to an extinct design like the e-stay.