So frictional force is equal to the coefficient of friction multiplied by the normal force, the only way to increase friction is to increase the co-efficient of friction or increase the weight over the area in which friction is occuring. As the surface area of a tyre increases, the pressure exerted on the tyre goes down, therefore these two factors counter act each other. Why therefore, do wider tyres result in greater traction?
yeah apparently the contact patch area remains the same and so traction won't be increased.. I reckon you'd probably gain something from wide tyres on lowering the pressure for the drags though. for cornering on the track, perhaps the contact patch is more effective being wide rather than long. dunno, I'm pretty sure this is all mentioned in the wheel and tyre bible if you google it.
It's inaccurate to assume that as the section width or tread width increases that the contact patch area also increases. Nor does it remain constant as [Vertical Force] / [Constant Inflation Pressure] suggests. Conceivably, it could decrease depending on the relative vertical stiffnesses. But what will change is the shape of the contact patch, becoming shorter in the longitudinal direction as it is made wider (assuming a constant load), and this may be partly responsible for more uniform unit loading over the area of the contact patch. All else equal, integrating a more uniform unit load and associated grip coefficient function over the entire contact patch should give more total lateral grip. The wider tire probably also has higher vertical and lateral spring rates, meaning less camber loss and lateral distortion in actual driving respectively.
so let me see if i understand..... a wider tyre will give a better (more even) load distribution across the contact patch, which will give better lateral grip. and i guess longitudinal grip (for forward acceleration). perhaps the distortion of a thinner tyre under forward acceleration make a wider tyre desirable.
I've always thought the same, howerver... if you use a softer rubber compound you will increase your tractions, but with softer compound tyre wear is increased and life is reduceed. To negate the increased tyre wear wider tyres are used. This is a important factor in motor sport. Thats how I see it
