beginner here so be gentle:-) i have a Jamis Explorer 3.0 with the 8 speed nexus hub. recently after climbing a steep hill, standing peddling, the chain started to contact what believe is refered to as the cassette joint on the hub, its a black connector that the cable goes through. the rub can be heard once every revolution but not for the entire revololution. does this mean something is broken or bent? or is it something that needs an adjustment? its almost as if the nut needs to come off the right side of the axel, and then the casette joint rotated out of contact with the chain, but i'm scared ****less to touch that hub or any part of it. thanks in advance.