W.W.
I think you are talking about "low profile" tires?
They are typically WIDER than "normal" tires and you only see about 1" or 2" of black instead of the "normal" 4"?
They are wider, so they have more contact with the pavement. They SAY they offer an "enhanced" steering and handling performance.
However, when I have ridden in a car with low profiles? I found that the ride was VERY hard and stiff.