Hydroplane and lifting off the accelerator

[Leafdriver333]

I have had a lot of RWD cars in the pacific NW where it rains 9 months out of 12 months.
I have never had a situation like that.
Crazy.

So the regen brake is mainly on the rear for RWD?

 

[Feathermerchan]

The regen is the car turning the motor so for a RWD it's all on the rear.

 

[MP3Mike]

So the regen brake is mainly on the rear for RWD?

Entirely on the rear. There is no motor in the front to provide regen.

 

[Leafdriver333]

Entirely on the rear. There is no motor in the front to provide regen.

That makes sense.
And yes, that's why the car spun because it is like locking up the rear wheels while the front maintains grip. That's what happens when you pull on the emergency brake in an ICE. The car spins.
AWD Tesla would be in better control in the same situation.

There you go, Elon. I just convinced a few folks to go for AWD instead of RWD.

When I buy a Model Y, I will have to go for AWD version as well.

 

[WilliamG]

Living in the Pacific Northwest (Seattle), RWD was definitely out of the question. I do think it’s an interesting scenario in the rain with regen on Normal - with RWD. This incident seems like something that shouldn’t happen, though perhaps the tire condition is the bigger issue. I’d be interested to know the tread depth on the rears in this case.

 

[MP3Mike]

This incident seems like something that shouldn’t happen, though perhaps the tire condition is the bigger issue.

Contributing factors include:

• the OP was going faster than everyone else we could see on that section of highway.
• The rear tires were significantly worn. (failure to rotate tires)
• his muscle memory for how to deal with that situation in a car without regen

 

[Leafdriver333]

In heavy rain or when below 37ºF, the regen should automatically limit itself, especially for RWD.

 

[Rottenapplr]

I have had a lot of RWD cars in the pacific NW where it rains 9 months out of 12 months.
I have never had a situation like that.
Crazy.

So the regen brake is mainly on the rear for RWD?

Yah anyone know?

 

[Rottenapplr]

In heavy rain or when below 37ºF, the regen should automatically limit itself, especially for RWD.

Jeeez I wish there was an option to turn it off. Like when you are canyon carving or inclement weather. It should be an option. Shoot I have a long range model so YOLO.

 

[ulrichw]

[...]

• his muscle memory for how to deal with that situation in a car without regen

Totally agree with the first two points, but I have to comment on this one (and I know you took this from his post):
Lifting in *any* car which is oversteering will make the oversteer worse, and possibly induce a spin.

Lifting transfers weight to the front and makes the rear light - giving more traction in the front and less in the rear - recipe for a spin.

The only exception to this is if you've induced oversteer with the throttle.

In general, the right reaction to sudden oversteer is to be neutral or slightly add throttle (this is very counter-intuitive).

Certainly, regen braking very well might have exacerbated the situation - but if OP meant that lifting was part of his "muscle memory", he learned performance driving from a source that teaches it very differently from what I've experienced. If he had done it "right", regen should not have been a factor.

OP: Kudos for sharing this embarrassing and expensive experience. I think the primary thing to focus on is not overdriving the conditions. I don't think you can blame the car for this one - certainly it could've done more to rescue you from your misjudgment, but the primary mistake was yours, IMO.

 

[Leafdriver333]

Totally agree with the first two points, but I have to comment on this one (and I know you took this from his post):
Lifting in *any* car which is oversteering will make the oversteer worse, and possibly induce a spin.

Lifting transfers weight to the front and makes the rear light - giving more traction in the front and less in the rear - recipe for a spin.

The only exception to this is if you've induced oversteer with the throttle.

In general, the right reaction to sudden oversteer is to be neutral or slightly add throttle (this is very counter-intuitive).

Certainly, regen braking very well might have exacerbated the situation - but if OP meant that lifting was part of his "muscle memory", he learned performance driving from a source that teaches it very differently from what I've experienced. If he had done it "right", regen should not have been a factor.

OP: Kudos for sharing this embarrassing and expensive experience. I think the primary thing to focus on is not overdriving the conditions. I don't think you can blame the car for this one - certainly it could've done more to rescue you from your misjudgment, but the primary mistake was yours, IMO.

Car started hydroplaning.

Your reaction is ...? You will add throttle?

With RWD Tesla, braking while you scream is the correct answer.

But I agree that driving too fast for the condition was the first contributing factor.

 

[Rottenapplr]

50 is pretty slow on the freeway. Looks like tires is the bigger factor.

 

[jerry33]

So the regen brake is mainly on the rear for RWD?

The motor is the brake on regen. The procedure is to not release the accelerator pedal fully because that will give you full regeneration braking power, just the same as you don't press the accelerator pedal to the floor all the time. Regeneration is not all-or-nothing, it's controlled by how much you ease up on the accelerator pedal.

 

[gbrgbr]

it rains frequently and heavily where I live. when driving in heavy rain I switch to a profile called "RAIN." it's the same as my nor al profile except decreased regen and chill mode.

 

[Broccoli2]

Totally agree with the first two points, but I have to comment on this one (and I know you took this from his post):
Lifting in *any* car which is oversteering will make the oversteer worse, and possibly induce a spin.

Lifting transfers weight to the front and makes the rear light - giving more traction in the front and less in the rear - recipe for a spin.

The only exception to this is if you've induced oversteer with the throttle.

In general, the right reaction to sudden oversteer is to be neutral or slightly add throttle (this is very counter-intuitive).

Certainly, regen braking very well might have exacerbated the situation - but if OP meant that lifting was part of his "muscle memory", he learned performance driving from a source that teaches it very differently from what I've experienced. If he had done it "right", regen should not have been a factor.

OP: Kudos for sharing this embarrassing and expensive experience. I think the primary thing to focus on is not overdriving the conditions. I don't think you can blame the car for this one - certainly it could've done more to rescue you from your misjudgment, but the primary mistake was yours, IMO.

So, First, I never said it wasn't my fault and I never blamed the car as a whole but it was a factor. I take complete responsibility. It was kinda like a plane crash. It wasn't one thing that caused this accident. It was a multitude of things I did or didn't do that caused it. All I'm saying is that the regen was one of those factors. I am not here to argue about how to drive. You must take all into account. It was 5:30 in the morning and I wasn't planing on sliding my 50+ thousand dollar car sideways down the freeway. Now, If I was doing the same thing is an equally powerful car on a bend in the road on a dry day and the backend broke loose and I wanted to keep it in the lane, I would ease off the throttle, I wouldn't just keep the tires spinning at the same speed unless of course I wanted to drift. That being said, when I say lifting I didn't mean drop the throttle completely. I would have said that. If you watch the video again you can see the backend started to go left (as the road was bending right). I started to lift slightly and it came back straight. Once it was straight, I then lifted more to slow down and that is when the backend broke loss again and stared to go right. at this point is where I kept steady on the peddle (where it was in the almost completely Lifted). The regen was really causing problems for my 5:30 am state of mind. What I should have done at that point is put more throttle into it to get to the neutral torque position. The rear tires in this are probably the leading factor, but it took a lot of factors including me and the regen.
BTW, I don't think this is embarrassing at all. No one is perfect especially me, haha. I do agree it is going to be expensive. My biggest expense will be my insurance policies going up. I have 6 different personal policies with 7 passenger vehicles, a Motorhome, Boat, 3 motorcycles and my business policies with 12 vehicles...

BTW, I disagree with this. "Lifting in *any* car which is oversteering will make the oversteer worse, and possibly induce a spin." that is not true. when you find yourself in an oversteer situation you lift off the throttle or if you are on the brake you lift off that. If you are on the throttle and you start to oversteer and you add throttle you will make it worse.

 

[Uncle Paul]

Glad that you are safe.

Simple explaination is that your front tires, with plenty of tread held the road as you would expect, while your rear wheels with little tread hydroplaned and lost traction.

If you simply feathered your throttle, you migh have got away with it, but if you lifted, the tires with no traction would again have hydroplaned and set you up for a spin.

Spin caused by mismatched tire, plus driving at excessive speed for conditions.

California freeways are notorious for having a thin film of oil that causes them to initially be very slippery on a first rain in a while.

 

[Feathermerchan]

Slippery? I thought it was hydroplaning.
I think the car could reduce/stop regen when it senses this condition. Just like ABS operates when sensing a skid or stability control when car is not going the direction desired (by the steering position). It did stay relatively in its lade and made one complete revolution. I wonder if any of that was due to stability control.

 

[ulrichw]

Car started hydroplaning.

Your reaction is ...? You will add throttle?

With RWD Tesla, braking while you scream is the correct answer.

But I agree that driving too fast for the condition was the first contributing factor.

[...]
BTW, I disagree with this. "Lifting in *any* car which is oversteering will make the oversteer worse, and possibly induce a spin." that is not true. when you find yourself in an oversteer situation you lift off the throttle or if you are on the brake you lift off that. If you are on the throttle and you start to oversteer and you add throttle you will make it worse.

Please read: Lift-off oversteer - Wikipedia.
Also, if you have the means and opportunity, I recommend driving in a skid car (SKIDCAR & SKIDTRUCK Systems: Complete Driver Training Solutions)

The reason most street car are tuned for varying degrees of understeer at the limit is the counter-intuitive nature of dealing with oversteer.

Lifting off the throttle is one of the worst things you can do if your car is already oversteering (braking is worse). Neutral, to slightly positive throttle is the right way to handle it in performance driving.

Note that drifting involves throttle too, but in that case, you're using *extreme* throttle to overpower the traction of the rear wheels and keep the rear sliding - that's a different situation.

In this instance, the right way to handle the situation was not to get into it in the first case (i.e., slow down).

BTW: I think hydroplaning is a probable mis-diagnosis of the situation. It was the bump in a turn that broke traction and started the car sliding. Once a car starts sliding, it doesn't stop sliding that easily, especially on wet pavement. This was simple over-driving.

 

[Leafdriver333]

Please read: Lift-off oversteer - Wikipedia.
Also, if you have the means and opportunity, I recommend driving in a skid car (SKIDCAR & SKIDTRUCK Systems: Complete Driver Training Solutions)

The reason most street car are tuned for varying degrees of understeer at the limit is the counter-intuitive nature of dealing with oversteer.

Lifting off the throttle is one of the worst things you can do if your car is already oversteering (braking is worse). Neutral, to slightly positive throttle is the right way to handle it in performance driving.

Note that drifting involves throttle too, but in that case, you're using *extreme* throttle to overpower the traction of the rear wheels and keep the rear sliding - that's a different situation.

In this instance, the right way to handle the situation was not to get into it in the first case (i.e., slow down).

BTW: I think hydroplaning is a probable mis-diagnosis of the situation. It was the bump in a turn that broke traction and started the car sliding. Once a car starts sliding, it doesn't stop sliding that easily, especially on wet pavement. This was simple over-driving.

Ok.
Good luck with adding throttle to the rear wheels after it breaks loose.
I will just slow down in inclement weather.

 

[ulrichw]

Ok.
Good luck with adding throttle to the rear wheels after it breaks loose.
I will just slow down in inclement weather.

Slowing down is the right behavior.

OP was talking about having performance driving experience - and blaming his "muscle memory". This is the part that I think is wrong.

Too much throttle induces oversteer in RWD cars, but so does decelerating too abruptly. In a situation like OP's, where the oversteer was not induced by the throttle, maintaining throttle would have been the best bet. Someone with performance driving "muscle memory" should remember this. Lifting is asking for a spin (search for "neutral throttle" in this article for some more info (particularly in the RWD section): Oversteer - Trackpedia).

I wouldn't recommend trying this unless you have opportunity to practice this - getting the timing and level of inputs right is very tricky - your best bet is to hope that the car's aids can rescue you.

BTW: The most important steps to recovery involve steering input - the snap spin in the opposite direction of the initial skid is a very common outcome for inexperienced drivers - nothing to do with regen, just a too slow reaction to the nearly inevitable counter-skid when the initial recovery takes effect.