Challenged a very short steep hill with the Explorer +1. I had tried several times with my conventional 27 speed bikes and never made it more than half way. With the Giant I was down to lowest gear on Sport 2 and almost did not make it, but I came through in the end. I was so impressed with the performance of this magic machine that I mused as to whether there really was a hill one could not climb. Anything steeper and both bike and rider would have collapsed. At least now I know what the limitations are for us as a combo anyway. Even so, still very happy with the performance of the bike. Pulse rate at time of climb? Almost 150.