I need to carry my marin on my roof rack, i carry normal bikes on the roof with the clamp type system, but my east peak is a full sus with square down tube

any ideas

Take a look at the Thule range of roof mounted cycle carriers. I regularly carry an Orange Sub 5 with it's oversized down tube and it fits no problem, you just adjust the down tube clamp to the size of the tube it needs to hold and then lock it in place.

thanks for the info