Was mostly a dirt track term.......Before modern chassis technology was developed, adjustable shocks, spring rates ,ect. ...to transfer weight to desired points of the chassis setup, cars were fairly rigid. "The floater" ...left front.....would be carried off the ground through most of the corners, touching down on straight-aways & slow speeds. These floaters were of different tread , narrower foot print, smaller diameter. ( mostly preference) ....possible thoughts were...less drag/friction. I am No authority ....just the way "floater" was explained to me back in the early '70's. (#56 Gene Schattschneider)