Yeah, it's to keep the axle centered. I didn't want to use a panhard bar because a panhard bar pushes the axle from side to side when the rear moves up or down (suspension travel). The next idea was a diagonal link, but a piece of pipe is very strong tensionally, but not comressing it. When you turn one way, you will be pulling on the bar (thus very strong) but when you turn the other way, you'll be pushing on the bar which may cause it to bend. Including an extra bar the other way, you are always pulling on one of the bars. The thinner one still needs some modding because as it is there, it is sitting loosely and you can just pull it apart.
