Re: GT2-A frame
If it was a steel frame you could probabally coherse the dropouts together but I guess aluminum doesnt respond well to bending. Either a hub swap ( Im pretty sure the shimano nexxus hub is 135mm and some guys are making hub adapters for those) and you can get them with a coaster brake. That means new spokes, a hub, and adapter. Or you can order an axel for one and rebuild your hub and replace the axel with the longer one. Good luck keep us informed on how it goes.
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