Putting it in park, or longpress for (P) - what's the difference?

[Ande]

P90D , I would assume "Park" (single short press) - mechanically locks bort front and rear wheels ? (but what about the differntial, in case of winter/icy parking)

It's also possible to press and hold the park button for (P) - which I assume operates the smaller, grey calipers.

How does it work, and when would one prefer one method over the other, and why.

 

[Ande]

(bort=both - unable to edit for some reason)

 

[boaterva]

The S manual says the parking brake is only on the rear wheels... have we seen different for the gray calipers (the separate parking brakes)?

What other parking brake method is there besides the button on the end of the shift stalk?

 

[HankLloydRight]

AFAIK, the parking button only engages the small rear calipers. No differential lock. That's it.

 

[whitecotton]

Parking brake on S and X is the two small calipers, one on each rear wheel. The front wheels have no locking mechanism.

 

[boaterva]

And something that may be useful to people... how to manually disengage the parking brake calipers if your electrical system fails, so you can roll the car onto a tow truck! A major problem that James Cooke had, and here's the other James, of James and Kate, to show how to release the brakes:

 

[Ande]

So far, there is no clear answer.
it seems those grey calipers are the (P) brakes. - on rear wheels only.
in what way are they better/safer than the normal "park" ? - the differential could be one reason, (when parking on a slippery surface.)
do we know for sure that the front wheels does not lock in ?

 

[boaterva]

What normal Park? What other park is there? Please tell us how *you* put the car into park.

 

[jjh1234]

What normal Park? What other park is there? Please tell us how *you* put the car into park.

I just tried wait the OP talked about. When I do a short press of the P button, I get the standard P indication in the P R N D display at the bottom right corner of the instrument cluster. When I do a long press (a couple of seconds) of the P button, I get an additional red (P) indication on the top right corner of the instrument cluster as well as the normal P R N D indication. I'm not sure what the difference is and that's what I believe the OP is asking as well.

 

[boaterva]

Well, one is supposed to unlock doors and all that. Does one do that and not the other? Doesn't a double tap do the door unlock if enabled? Is that the same as a long press?

The manual says whenever in park, the parking brakes are applied. Touch Park (the button) again to unlock doors...

 

[jjh1234]

Well, one is supposed to unlock doors and all that. Does one do that and not the other? Doesn't a double tap do the door unlock if enabled? Is that the same as a long press?

The manual says whenever in park, the parking brakes are applied. Touch Park (the button) again to unlock doors...

I'll have to check. I know I just enabled "Door Unlock on Park" or whatever it's called yesterday and it seems to unlock on the standard short press. I've never heard of a double short press. Maybe that unlocks the doors if "Door Unlock on Park" is disabled?

 

[boaterva]

I'll have to check. I know I just enabled "Door Unlock on Park" or whatever it's called yesterday and it seems to unlock on the standard short press. I've never heard of a double short press. Maybe that unlocks the doors if "Door Unlock on Park" is disabled?

Interesting idea. The manual says the 'P in parens' symbol means the parking brake is on. I have no idea what pressing the button and NOT getting that means, as it says when you press it once, you are in Park.

I see the confusion, as you would think you would always get the rear (only) parking brakes applied. Can't think this is different for European builds?

 

[spottyq]

I just tried wait the OP talked about. When I do a short press of the P button, I get the standard P indication in the P R N D display at the bottom right corner of the instrument cluster. When I do a long press (a couple of seconds) of the P button, I get an additional red (P) indication on the top right corner of the instrument cluster as well as the normal P R N D indication. I'm not sure what the difference is and that's what I believe the OP is asking as well.

I am pretty sure there is no difference when the car is stopped (except for the extra red 'P'; in practice only the rear parking brake calipers engage).

But the difference is when you try to do that while driving (in D, above a certain speed) : a short click or flick of the stalk should put the car in N (plus it will probably beep angrily at you) while a long press would actually engage the rear parking brake calipers; to be used as emergency brakes.

This is all straight from my head (to take with a grain of salt), but should be easy to test for anyone wanting a final answer.

 

[HankLloydRight]

From the Model S manual:

Note: The parking brake operates on the rear wheels only, and is independent of the footoperated brake system.

 

[HankLloydRight]

in what way are they better/safer than the normal "park" ? - the differential could be one reason, (when parking on a slippery surface.)

There is no differential lock. You keep mentioning a slippery surface -- how is locking both rear wheels with calipers any different from a differential lock (if one existed?)

do we know for sure that the front wheels does not lock in ?

Yes*

*EDIT: For cars with the rear parking brake calipers. It's possible the front brakes do lock for newer cars without the rear brake parking calipers. I don't have one of those, so I don't know for sure.

 

[GaryREM]

Don't for get that newer cars don't have the parking brake caliper.

It was originally needed because the brakes were hydraulic only.

 

[Ande]

You keep mentioning a slippery surface -- how is locking both rear wheels with calipers any different from a differential lock (if one existed?)

If you park on sloping ice, with a traditional park (locked motor) , with differential free to move, once one wheel slips, the other can just roll downward - as long one is slipping.... with (P) which I can hear engange, brake calipers hold each wheel, so if one slips, the other is still holding fast.

What I hoped to learn , is that there is a park (motor lock) on the fron wheels as well, providing more friction.
Regards
André

 

[HankLloydRight]

If you park on sloping ice, with a traditional park (locked motor) , with differential free to move, once one wheel slips, the other can just roll downward - as long one is slipping.... with (P) which I can hear engange, brake calipers hold each wheel, so if one slips, the other is still holding fast.

Ok, you made it sound like a differential lock on ice would be better than a brake caliper lock.

Also, the differential in the Tesla is a simple differential, not a LSD. So if there was a diff lock, it would lock up both wheels anyway.

 

[boaterva]

So newer (what's newer?) only have one caliper on each wheel? I'll have to check this out when I get a chance to look at current cars, first I've heard of this. I thought they all had the separate ones so one pair was locked when in Park and the others were completely independent.

 

[jjh1234]

Ok, I just did some more testing with the loaner MX75D I have. It was made on 5/17.

It does NOT have the extra little caliper on the rear wheels (or the front for that matter), whereas my 11/16 MS75D does. I'm not sure if that's a MS / MX thing, or a manufacture date thing. However, I still hear the whirring noise while applying and releasing the parking brake like the models that have the extra caliper in the back. From that, I assume the actuator has been built into the main caliper now.

With a short press of the Park button the P is activated on the P R N D display. If I press the Park button again and hold it for a couple of seconds, I hear a short whir from the rear calipers and the red (P) comes on as well. I believe the parking brake is bring applied with a little extra torque. If true, I see this as useful when parked on a steep hill, especially with a trailer.

With two quick short presses, the automatic parking mode is activated and I am prompted to pick a parking direction and exit the car.

With a short press then a second short press a few seconds later, the doors are unlocked if the "Door unlock in Park" is disabled. Otherwise the doors are unlocked on the first press when the "Door unlock in Park" is enabled.

Also, on another note, this MX75D seems just as fast as the MS75 made in 7/17 I had yesterday that had the speed upgrade. This does seem to validate the pre-July loaners and demo units have been upgraded to the faster acceleration. I will post in the other thread as well.