NO IT IS NOT LEFT THREAD i just took 1 of those nut out about 2 hours ago. it is standard thread. i made a tool for removing the nut. go to the hardware store and find a nut that will fit inside the nut on the frame. once you have that get a bolt that fits your nut from the hardware store, and weld it together then you can get an air impact in there and it will come apart. you might want to soak it with some pb blaster for a couple hours but it will come out. good luck