Originally Posted by Caliper

Sorry, there is more to tires than physics 101. The simple friction equation is all well and good when you have fairly rigid smooth bodies in contact with each other. Rubber and tires are not this however, they are very dynamic and flexible. If contact patch didn't matter, drag racers wouldn't drop their tire pressures. But, lower pressures on the same sticky tire DO result in more grip because of the larger contact area. More rubber interfacing with the road means that there are more points of mechanical interface where the rubber is physically interlocking with the pavement surface and to make the tire slide, those pieces of rubber must be physically sheared off (the source of skidmarks)


Width, even at the same tire pressure also influences lateral traction on because of tire slip angle while cornering and the contact patch shape, it all has to do with how the contact patch deforms due to lateral forces. Simply, a long/skinny contact patch cannot support the same slip angle because the tire sidewall must deflect more and at some point cannot. I'm not sure how much this carries over to bikes due to the different tire shapes vs cars, but in cars wider tires of the same compound do most certainly increase cornering grip.