bigger boggies?

you need to change youre rear axle or get new rails to run bigger wheels . bigger wheels alone not only move the track back but also down words . so youre track would be riding on youre rear wheels instead of youre rear wheel and hyfax . id go with rails if you can they look alot cooler then stock rails and are stonger , an offset rear axle really does nothing in the strength or looks department and cost just about the same as a set of rails