Ivan Vegvary wrote:
Watching "Classic Car Restoration" the host made the statement that the
brake caliper on the restoration car (1969 Alfa Romeo) had twice the force
on the rotor (compared to single piston calipers) because it has a dual
opposing pistons, one pushing on each of the brake pads.

Is this a myth, like 2 cars, 50 mph each traveling at each other, creating
an equivalent collision of 100 mph? (In reality it is equivalent to one 50
mph car slamming into an unmovable (50mph reaction) object, e.g., concrete
wall, 5' diameter oak tree, etc.

No. Energy of a moving object is 1/2 mass times velocity squared. Total
energy disspiated in a two car crash is the sum of the energy of each
car. A 2 ton car slamming into a wall at 50 miles per hour dissipates 1/4
of the energy of a car going 100 into a wall. Two cars that compact the
same way driving into each other is really like two cars slamming into a
wall. If you consider the rate of deceleration the only measure of a
crash, the original statement is sort of true, but still misleading.





For example, if a single piston caliper is able to apply 500lbs. of push,
there would have to be 500lbs. of resistance from the other side of the
caliper frame. Total 1000 lbs. 'squeeze'. All things being equal, if in a
dual piston caliper, with each piston pushing with 500 lbs. force, doesn't
the rotor experience the same amount of friction against turning?

Where is my thinking wrong?

Thanks for replies,
Ivan Vegvary