Originally Posted by
cyccommute
Surly LHT and Cannondale touring bike used to have the longest chainstays at a bit over 18”. The reason was to keep as much of the load between the axles as possible for a stable ride.
The 460mm chainstays featured on many touring bikes like the LHT are certainly longer than most bikes use, but I wouldn't call them "the longest." They're not even really the longest among bikes of their style, for example the Salsa Marrakesh has 472mm chainstays if the dropouts are adjusted to use their farthest-back position.
If you want to see
really long chainstays, look at stuff that Grant Petersen designs. A lot of his models go over 500mm.