Quote Originally Posted by curtis265 View Post
Ok let's not take cornering into account then to make this a bit more simple - straight line only.

Traction is the ratio between the forces exerterd by a vehicle through the wheel, and the weight supported by the wheel. - forces in two directions which have no effect on each other. A 1000 kg car would be able to put down 10 times the force to the ground than a 100 kg cyclist - as Fallenangel said.

I do too believe that a fatter wheel would increase the traction... but the pressure applied to the ground would be less because the weight would be more spread out. This would mean that the car can exert less force to the ground...

The above paragraph makes sense to me, but i can't accpet how a fatter tyre would be less forceful, and have never figured out how to disprove what i just said... Someone do so! and save me before i go insane..

With a high pressure tyre. (more pointed). There would be less road contact.
But the force is greater.
You lower the pressure you have less force but more contact.
And it also depends on the drive type.
A rear wheel drive will have alot more force applied to the wheels during take off or launch, and a front wheel drive will have less force applied to the driving wheels, as a vehicles tends to lift off during take off, exerting all the force towards the rear.

Ever tried doing a burnout in a front wheel drive?
High pressures will bunny hop.
Lower pressures will let it spin.

Its very hard to get into detail. But lets say you have 35psi with 5" effective road contact with 200kg on each front wheel. 5x200x35 = 35000 units.
Compared to 25psi with 8" effective contact. 8x200x25 = 40000 units. Even with 7" effective road contact, it equals up to 35000.

That is not a formula. But its something i made up to prove my point.
With 35 psi of contact on 5" effectively on the road. You have 35psi @ 200kg on that area.

While having 25psi @ 200kg with 7 or 8" effective area contact, You still have the same amount of forces but its more spread out.

Its hard to explain. But put into consideration. That tyre pressures vary with different conditions.
and what I wanted the point i wanted to bring across is that if you can have the same amount of traction at 35psi and 25 psi. Wouldnt it be better to be at 25psi to leave for changes in temperature, surfaces, load etc etc?

Force applied to the ground is not all based on tyre pressures.

My head hurts.