Hacker News new | ask | show | jobs
by kurupt213 1382 days ago
I think you are looking at this wrong. It should be surface area of rotor/brakepad interface per lb of vehicle
2 comments

Just about any car can brake hard enough to lock up all 4 tires and enter a skid (or activate ABS to avoid this)- the limiting factor to braking distance is friction between the tires and the ground.

Scaling for static friction between rubber and asphalt does not follow the friction equation you are taught in high school physics class. Generally, for a given weight of vehicle, a larger tire surface area is able to produce more maximum braking friction. In other terms, minimizing the surface pressure and maximizing the surface area at the contact patch increases maximum braking friction.

Modern brakes can get a lot hotter before brake fade. Until the brakes get too hot it is just a matter of brake pressure. Modern cars universally have disk brakes which shed heat better. Larger vehicles also have bigger tires which leaves more room for brakes.

In short while you are not wrong, in practice even the worst numbers are still more than good enough that brake performance isn't an issue.