Size aint everything. Fats will give you straight line grip on a dry super flat sticky drag strip.
Wider tYres are probably gonna give a bit better straight line take off traction on a dry road.
Once you introduce cornering (its usually unavoidable it seems ) and rough / not dry surfaces its a whole different kettle of yabbies.
Its all about the coefficeint of friction with da ground. This is gonna be determined by a LOT of very co-dependant factors.
For example, area in contact with the ground, and downward force per unit area. As you can see these two factors are a trade off. If we put bigger tyres on, there is more area but less force per unit of area.
The hot tip is that the best answer doesnt necesarily lie up the big fat tyre end of the scale, but rather a balance of these two and about a hundred million other factors.
The main point of this post was to demonstrate that the word for the black rubbery things that go round our wheels does not have a fuckin "I" in it in our country. Please be warned or the next offender will have the national spelling & grammar police kickin your freakin door in!!!