In the strictly theoretical sense, increasing just the width of a tire does nothing to improve acceleration or braking traction.A wider tire will have a shorter contact patch, which is precisely what youdon’twant when the goal is maximum longitudinal grip. The replacement-tire development manager at Bridgestone Americas, says that a longer, not wider, contact patch helps you climb faster to maximum braking grip.

The problem with this theory is that the only time you can change one and only one variable is in simulations. In the real world, varying one detail drives other changes. For example, widening a tire but maintaining the same aspect ratio leads to a taller sidewall.