[BoostandEthanol]

There’s something incredibly entertaining to me about even this well researched article struggling to find a reason for why wider tyres have more grip.

As I understand it, this is because tyres are still somewhat of a mystery, and anyone outside of a laboratory really doesn’t know shit. The best explanation I can think of is due to tyre load sensitivity. The friction coefficient of rubber decreases with normal force (E.g, a heavily loaded tyre has a lower friction coefficient), which is a pretty well accepted fact, this is one of the methods engineers will use to tune the handling of cars. This means a wider tyre has a lower force per unit area of the contact patch, which means it’ll have a higher friction coefficient.

Now that sounds plausible to me, but that’s just my best guess explanation.

[InCityDreams]

https://www.bicyclerollingresistance.com/

gives good tyre advice (obviously not car tyres, but info is there)