9in drum brakes
Locking up the wheels is the least useful measurement of braking performance that there is. It literally tells you almost nothing about the braking capability of the car, and it is the worst way to stop quickly.
When the wheels are locked, the brakes are effectively useless and all the stopping is being done by the sliding tire. The coefficient of friction for a sliding tire is lower than for a rolling tire. So even the tire is providing less stopping force than it could be, you can stop the car faster with a still rolling tire because there is more friction force available to the rolling tire. Not to mention all the kinetic energy that will be dissipated by the brakes because the rotor is still turning. The entire point of ABS is to keep the wheels from locking up and staying that way. If locking up the wheels was best, there’d be no reason for ABS- anyone can stomp on the brakes and lock them up.
Keeping the wheels rolling maximizes both the friction you get from the tires and the heat you can dissipate with the brakes, which is why that’s the fastest way to stop. And the safest, because if you’re not locked up you can still steer.
Brakes are really simple. They convert kinetic energy into heat. The faster they can generate and dissipate heat, the faster you will stop. Disk brakes are more efficient at both, and are especially better at dissipating heat.
None of these cars with factory brakes stop “amazing”. The factory disk/drum cars do ok, and they’re a significant improvement over the drum/drum cars. But even a basic modern eco-box can stop dozens of feet shorter than one of these cars with a factory disk/drum set up, even equipped with better radial tires. The articles I’ve already posted show that easily.