The FX can handle hard packed dirt and grass, or a well maintained stone dust/crushed limestone path. Any kind of loose surface, ruts, or roots is pretty much out of the question. The 7100 is no better - don't let the front suspension fool you into thinking this is an off-road bike. It is a very comfortable, upright, low speed kind of a ride. If you are planning from the start on riding mostly off-road, then I don't think either one of these is a good choice.