with the bar connected the front end is not allowed to flex side to side. This is great for the road and handling, but sucks offroad. When disconected the axle id free to flex and add a great deal of offroad capibility. They are connected w/ 4 bolts and you can either take the stock one's off everytime, or buy the one's that come apart. I got the one's that have a lower pin and upper pin, i think they are the easiest to get on and off. There are a couple pf mfg just shop around..........