[FabHK]

GP didn't claim that braking distance was larger because of higher mass. Rather, because of the higher centre of gravity the ABS has to be calibrated differently, leading to weaker braking, thus larger braking distance.

I have no expertise in this, but seems prima facie plausible.

[Someone]

I think simongr3dal’s remark isn’t about them taking longer to stop, but about the use of the term calibration.

ABS is a feedback loop: brake faster until just before the wheels start slipping. That doesn’t need calibration.

There may be additional logic in ABS systems for corner cases that requires calibration, though (for example, if your front left wheel has lots more grip than the other ones, can you brake full on it and keep the car going in a straight(ish) line?), but I don’t see how higher CoG would be a factor there.

[FabHK]

Ah, fair enough, that makes sense. You're right, if we posit that ABS is purely to prevent slipping, that would imply that it always goes for maximum braking.

> I don’t see how higher CoG would be a factor there.

Could be that the "additional logic" (whether we call it ABS or something else) aims to keep certain values (such as longitudinal or lateral acceleration) within bounds (thus releasing brake pressure when approaching those bounds), and those bounds are tighter with higher CoG.

I remember the Mercedes A-Class (with pretty high CoG) rolled over in the Swedish Moose test initially, until that was fixed with Electronic Stability Control (how?).

https://en.wikipedia.org/wiki/Moose_test#1997_Mercedes_A-Cla...

[Someone]

https://en.wikipedia.org/wiki/Electronic_stability_control

“When ESC detects loss of steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer”

So, ESC activates the brakes harder than the driver indicates through the controls, while ABS activates the brakes less hard than the driver indicates through the controls.

Both systems use the same sensors and have to agree on who’s in control when, though, so I can see people lumping them together. Wikipedia also says (https://en.wikipedia.org/wiki/Electronic_stability_control#C...)

“ESC is built on top of an anti-lock brake system”

and (https://en.m.wikipedia.org/wiki/Electronic_stability_control...):

“Just as ESC is founded on the anti-lock braking system (ABS), ESC is the foundation for new advances such as Roll Stability Control or active rollover protection that works in the vertical plane much like ESC works in the horizontal plane. When RSC detects impending rollover (usually on transport trucks or SUVs), RSC applies brakes, reduces throttle, induces understeer, and/or slows down the vehicle.”

In the end, there can be only one set of commands that get sent to the brakes, throttle, etc, so these systems must be interconnected, making the terms more marketing than indicators of specific systems in the car.

By the way, I was surprised to read how old ABS is. https://en.wikipedia.org/wiki/Anti-lock_braking_system#Early...:

“The concept for ABS predates the modern systems that were introduced in the 1950s. In 1908, for example, J.E. Francis introduced his 'Slip Prevention Regulator for Rail Vehicles'.

In 1920 the French automobile and aircraft pioneer Gabriel Voisin experimented with systems that modulated the hydraulic braking pressure on his aircraft brakes to reduce the risk of tire slippage”

[cdash]

The future is electric vehicles which while heavier have a lower center of gravity.