Short press vs long press of "Park"

[stopcrazypp]

Despite doing a search on the forum, I did not come across this thread until I posted a similar one under the Model X category. I suspect the 3 and X brake systems are different as on my X I have a seperate mechanically operated caliper that is the parking brake. This is still a lot of mystery on this subject and I don't know why it is not clear. The long and short presses do something different as confirmed by the fact that only a long press activates the "P" icon on the screen. I find it hard to understand that the long press "exerts" more pressure on the parking brake. Parking brakes are either on or off. What if you parked on a hill, would you car roll away after just initiating the short press because "low" pressure has been applied. I don't think so. This would be problematic for Tesla. I have not read any documentation from Tesla to that affect.

Saying parking brakes can only be on or off is kind of like saying brakes can only be on or off. Sure we may get that impression from the typical cable based parking brakes most of us have used traditionally. In that case, the mechanism only allows applying it in one way, so unlike a brake pedal, there is no way to really vary the pressure.

I don't know about the X, but in the 3/Y, it is a screw drive. It is not out of realm of possibility a second engagement can make it clamp harder (just like how you can overtorque a screw).

It has been observed engaging the official "parking brake" applies the caliper a second time and the sensor voltage goes from 1.75V to 4.5V, so there may well be a stronger clamping force from that engagement.

Difference Between park & PARK

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As for whether that makes the difference between a car rolling down the hill vs not, that is very hard to say, but at the very least there does seem to be some difference.

 

[BobX]

My son (who also owns an X) came up with another explanation. He thinks that both the long press and short park press activate the caliper. But they do it through different electrical circuits so that if the short press circuit fails for any reasons, the long press circuit still works. He may have something there and like his father, he is generally very smart.

 

[rpiotro]

I'll repost this. I think real world experience matters.

Short press vs long press of "Park"

Also there is emperical evidence that a long press does something different, namely that it applies the brake a second time and at a higher voltage. It's also significantly louder when it engages.

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