Originally Posted by
zukahn1
The rear chain stays and dropouts on the Trek and Miyata are too short to get a dingle speed to work nicely. For this you would need a frame set with fairly long slanted dropouts and bit more chain stay length to allow for changing between gear setups without changing the chain length or switching chains.
Also the longer the stays the better your chainline will be. Personally I am a purist and the desire for an optimal chainline would trump the desire for two cogs. But I also live in sort of ideal fg terrain.