Quote:
Originally Posted by GTO Braking has always been an area where cars blow bikes out of the water because of the 4 contact patches. Correct? |
I'm going slightly off topic but, yes and no. A car clearly has the potential to brake with more deceleration due to having more rubber, less weight transfer for the same deceleration due to a low centre of gravity height versus wheelbase. While the argument in favour of the motorcycle is that it is much, much lighter hence has lesser inertia to overcome. You expect a truck to stop slower than a car, so why not extrapolate that argument to bikes? Let me try to break (haha!) it down.
While for acceleration the light weight of the bike helps in a better power to weight ratio, the physics in deceleration is different.
Firstly, the force on a vehicle when stopping is:
F = ma
Where F is the force on the vehicle, m is its mass and a is the acceleration (negative in this case).
Next, that force is applied to the tires via traction as follows:
F = μW
Where W is the weight of the vehicle, and μ is the coefficient of friction.
The weight of the vehicle is its mass, m, times the gravitational force, g, so:
F = μmg
The maximum stopping force that can be applied is the maximum frictional force that the tires can cope with, so:
ma = μmg
What all this shows is that we can cancel the use of the variable m as it appears on both sides of the equation. In simple terms,
it means that mass has no bearing whatsoever on stopping distances. The equation to thus show the maximum possible deceleration is
a = μg
So (negative) acceleration equals the coefficient of friction of the tires, multiplied by the gravitational force
Therefore our light bikes are irrelevant when it comes to braking. Cars have 4 wider contact patches so they are better at braking. Case closed........well not quite.
The reason is that some sporty motorcycles have better brakes and tyres than most cars. So a Street Triple RS for example, will out brake most hatchbacks and family sedans, but if you get a remotely sporty car, the reverse will be true. Rider and driver skills play an important role too.