Originally Posted by
HillRider
Surly has offered 26" (ISO 559) rims on their small frame LHTs for quite a while and predate the current 650b fad. I assume they did it to achieve adequate toe clearance on small frames without distorting the geometry too much. The same reasoning Georgina Terry used for fitting 24" front wheels on her small bikes intended for women.
Surly originally said it was for the easy availability of 26" wheels and tires. That was true when almost all MTB's used 26" wheels.