Sorry, I was unclear. I was talking about the Tracks functionality (Vehicle/Output/Tracks) that lays down splines to sweep. :-)
I'm working on a 5-axle chassis with 3 steering axels and I thought that Tracks would be a good way to illustrate the path of each wheel through a turn. With reverse steering (brilliant function!) on the last axle, you get a pretty interesting pattern. But not to worry - I can put tracer objects in the Wheel containers as a workaround.