The three wheel one. You rig the car so that
one wheel is off the track. This makes a
huge difference in the time, and it's legal
as far as I know.

Yep, it's legal. And it's funny too. A lot of parents will accidentally
get the wheels aligned that way then come to the workshop and ask us to
help them fix the car so all the wheels are touching. So we do .

Tillman