No handbrake on Model S

[Stuart]

In my test drive on Saturday I was interested in the creep/no-creep issue.

On a slight uphill slope and no foot on either pedal, I let the Model S come to a stop, and then it started to roll backwards.

In a manual car I'm used to using the handbrake to stop this, but the Model S has no handbrake. I used a slight pressure on the accelerator to balance it and mostly stop the roll.

In such a short test drive I didn't get a chance to experiment more, to see if perhaps a brief press on the brake pedal would cause the Model S electronics to lock the wheels and prevent the roll.

Anyone else have any observations to report on this?

 

[Lloyd]

i believe it was reported on another thread that a 'hill hold' function was planned as a software update in the future.

 

[doug]

We experienced some roll back too. I kinda prefer to be able to free roll myself, but if there's no hand brake, I guess there should probably be a hill hold feature.

 

[spatterso911]

I'm presuming it won't be an issue just to keep foot on brake while on a hill? I figure it will drive like any automatic. I will try to evaluate those dynamics if there is a hill available on my LA test drive.

 

[Stuart]

I'm presuming it won't be an issue just to keep foot on brake while on a hill? I figure it will drive like any automatic. I will try to evaluate those dynamics if there is a hill available on my LA test drive.

Yes, of course keeping your foot on the brake pedal works.

But when you take your foot off the brake pedal, the car might start to roll backwards. I know a lot of people seem to think it's okay to roll back "a little bit" when starting, but (at least when I took it) a "hill start" was part of the British driving test, and if you rolled back even a little bit you failed.

Everyone was expected to know how to use the handbrake, let up the clutch pedal until the clutch starts to bite, and apply the right amount of accelerator pressure so that as you release the handbrake the car moves forward instead of backward. With tight parking in places like London, if the car rolled back even an inch or two you might hit the car behind. (An if you took the test in an automatic car you got a special restricted driving license that in effect said "doesn't know how drive a real car" which could limit your ability to rent a car.)

 

[spatterso911]

Only reason I ask is that on my M5, if you hold the brakes on a hill, afterwards, it holds the brakes for a second, giving you time to hit the accelerator. Voila, a rudimentary hill hold function.

 

[Jason S]

Might turn the 'creep' feature on for the S because my wife is used to automatics. It should hill hold well enough with that on, I think.

 

[Grendal]

There should be an electronic button on the 17" screen you can push to "park" the car in place. The beauty of the S is that you should be able to mimic any standard behavior of a gas car. Those features should be able to be modified to fit the driver's comfort level. The tricky part for Tesla will be to avoid extreme modifications that could be potentially dangerous.

 

[J in MN]

But when you take your foot off the brake pedal, the car might start to roll backwards.

Two pedals, two feet. What is the problem?

 

[kendallpb]

I'm confused, or just tired. I think y'all are just talking about while you're in it and the car's on and you're "in drive" so to speak (does it have a neutral gear?!).

But when you get out of the car, what happens--does it have a park "gear" for lack of a better term? I presume one can actually park on a hill . . . when you turn the car off, does it just automagically put on the equivalent of a hand or foot parking brake (the parking break, minus the hand/foot bit)???

Apologies for my ignorance here. I'm uses to manual and automatic, all with parking breaks (whether hand or foot), so I'm probably wandering off-topic but realized I don't know how this aspect works.

 

[olanmills]

Yeah, it has Park, Reverse, Neutral, and Drive. A parking brake is automatically engaged when you set the car in Park, and it's disengaged when you disengage from Park. You can't set the parking brake independently.

When you can set the parking brake independently, you can do different things, most commonly of course, to prevent the car from rolling on a hill when starting/stopping with a manual transmission. Also, especially with a handbrake, you can use it to drift or perform other similar manuevers.

 

[daniel]

Isn't a hand brake a safety feature? I've never liked foot-operated parking brakes. If the brake pedal fails, a hand-brake is a fall-back to stop the car. Far from ideal, but better than nothing. With a foot-operated parking brake, it's pretty much all or nothing. With no driver-operable parking bake at all, you have nothing if the brake pedal fails.

 

[Trnsl8r]

I read that Model S will set the car in P automatically if you leave the car, meaning you can actually leave it in D, jump out of the car, it will sense that there is no weight on the driver's seat and put it in P. One of the weekend's test drivers put this to the test and it worked. (Sorry, too tired to try and find the post.)

 

[gocken2]

Isn't a hand brake a safety feature? I've never liked foot-operated parking brakes. If the brake pedal fails, a hand-brake is a fall-back to stop the car. Far from ideal, but better than nothing. With a foot-operated parking brake, it's pretty much all or nothing. With no driver-operable parking bake at all, you have nothing if the brake pedal fails.

The model S "brakes" with the regen when you lift your foot off the accelerator. You can sort of think that the brake pedal is the backup since there are still 2 methods of slowing the car.

 

[Lloyd]

Isn't a hand brake a safety feature? I've never liked foot-operated parking brakes. If the brake pedal fails, a hand-brake is a fall-back to stop the car. Far from ideal, but better than nothing. With a foot-operated parking brake, it's pretty much all or nothing. With no driver-operable parking bake at all, you have nothing if the brake pedal fails.

You can still put it in park. The rear wheels will lock up and the car will stop. You still have the same safety functionality, and actually more. 1. Regen needs little brakes at all. 2. Brake pedal 3. Park, actuating the parking calipers.

 

[loganss]

You can still put it in park. The rear wheels will lock up and the car will stop. You still have the same safety functionality, and actually more. 1. Regen needs little brakes at all. 2. Brake pedal 3. Park, actuating the parking calipers.

Isn't the regen bullet negated if a driver selects the less aggressive regen which would allow the car to coast longer?
I'd like to get confirmation that shifting into park while driving would be a similar effect to pulling on a hand brake.

 

[spatterso911]

I'm just making an educated guess, but I suppose that is what I do for a living, so here we go...

The traditional automatic transmission park gear locks the transmission gearing, with the parking brake locking the rear wheels. Manuals can lock the transmission by just leaving the car in first after you stop. BMW's SMG insists you leave the car in gear when you stop and will warn you if you haven't. It doesn't have a P selection. Since there is only one gear on the Model S, and many other hybrids/electrics, the transmission does not get "locked" in park, it actuates the rear secondary calipers to lock the rear wheels. this is why it is plausible that in an emergency situation of brake failure, putting the car in park would cause actuation of the brakes. Same as if you yanked on the E-brake lever.

 

[jerry33]

Isn't a hand brake a safety feature? I've never liked foot-operated parking brakes. If the brake pedal fails, a hand-brake is a fall-back to stop the car. Far from ideal, but better than nothing. With a foot-operated parking brake, it's pretty much all or nothing. With no driver-operable parking bake at all, you have nothing if the brake pedal fails.

The DS-21 had a knob with a "J" slot that you could use remove the ratcheting from the parking brake and actually use it as an emergency brake. The parking brake actuated a separate set of pads on the (giant) rotors, so it was very fail-safe. And that was over forty years ago.

 

[olanmills]

I'm just making an educated guess, but I suppose that is what I do for a living, so here we go...

The traditional automatic transmission park gear locks the transmission gearing, with the parking brake locking the rear wheels. Manuals can lock the transmission by just leaving the car in first after you stop. BMW's SMG insists you leave the car in gear when you stop and will warn you if you haven't. It doesn't have a P selection. Since there is only one gear on the Model S, and many other hybrids/electrics, the transmission does not get "locked" in park, it actuates the rear secondary calipers to lock the rear wheels. this is why it is plausible that in an emergency situation of brake failure, putting the car in park would cause actuation of the brakes. Same as if you yanked on the E-brake lever.

In the Model S though, engaging P, is not a simple, single step. You have to shift to N, and then push the lever in to engage P.

 

[MitchL]

In the Model S though, engaging P, is not a simple, single step. You have to shift to N, and then push the lever in to engage P.

Sure about that? At the end of my test drive they just told me to press the P button. I might not remember what I did that day though. I might have switched to N without thinking.

/Mitch.