While at a driving school in Utah I was able to participate in an interesting exercise involving different tire and wheel sizes.
Three identical Ford Mustang GT's were outfitting with different tire and wheel packages.
Car #1 was fitted with OE 17x8 wheels with 235/55-17 tires
Car #2 was on 18x9.5 Ford wheels with 245/45-18 tires
Car #3 sat on the same 18x9.5" wheels with 285/40-18 tires
We then ran them through and AutoX course. The results surprised most of the participants.
Car #1 predictably under-steered but, was easy to control and push to the limits of traction.
Car #2 was razor sharp when responding to any driver input. It offered the best feedback allowing for the fastest lap times for all of the participants.
Car #3 while offering more grip in steady state cornering, felt very vague and disconnected from the driving experience. All driver inputs were met with delayed response and a sluggish feel. When you are missing your marks due to sidewall deflection inconsistencies it can be very unnerving especially at speed.
So, in the end the 245 width tire on car #2 was able to turn faster laps than car #3 even thought the tire was about 1.5" narrower. From an appearance stand point those 285's on car #3 did have an aggessive stance.
My name is Luke Pavlick and I am a Car Guy