Just changed to a narrower, higher profile rear tire and the results are positive so far. The bike turns much easier. It falls-in with little effort. Seems like power steering! And the ride is improved too. The 60 series sidewall seems to absorb road irregularites better.
Was: Michelin Macadam 100X in a 180/55-17
Now: Michelin Pilot Road in a 170/60-17