I had a 2019 Radius E and I had troubles with it tracking straight. I needed up sending mine to the dealer. It ended up being something with the adjustment on one of the control levers. It wasn't the allen set screw, rather it was something to do with the connection between the lever and the hydrostatic drive. These machines use dampers for the control levers and I believe that there was either slack on the one side or the connection between the damper and the lever had to be adjusted. When I got it back from the dealer it certainly felt much better and drove straight.