Time for a new CT.

[willtill]

I run a Yokohama that is very close to the same diameter as the oem. Just a bit bigger which which brings the speedo into sink with the GPS. With #40 psi it handles very good.
Soft side walls which give in corners and put a good patch of rubber on the road.

I assume your Yokohama is not a run flat?
I run 26psi in my Michelin Alpine which is a run flat. Higher pressures don't seem to work well in my run flat car tire...