What's the expert's opinion on how to handle a hydroplaning Model S AWD at highway speeds?

[PhilDavid]

Just thought I'd ask this to see what you all have to say now that cold weather, rain, fallen leaves along with snow and ice will be coming our way the next few months.

What's the expert opinion/best practice on how best to handle a hydroplaning Model S AWD at highway speeds?

I'm thinking the best thing to do is to steer the car where you want it to go with deliberate and firm but moderate movement of the steering wheel towards the center of the lane you want to be in but to make no harsh and abrupt steering movements. At the same time not slamming on your brakes or letting go of the accelerator as that will cause max regen but rather ease off on the accelerator to slightly reduce the speed so the deceleration input is mild.

Is this the best approach or am I missing something?

 

[croman]

Don't steer just lay off accelerator slowly and you can regain traction. Car is heavy and traction control instant response. Just don't attempt to overcorrect.

 

[murphyS90D]

Back off of the accelerator pedal to the "zero" point and keep it there until the car slows down. Regen can be modulated from zero to maximum. Maximum is when you are off of the accelerator pedal. Pressing the pedal gradually reduces the regen until you reach the zero point where there is no regen and no acceleration. Pressing further begins to apply acceleration.

 

[UncleCreepy]

Your safest bet is not to hydroplane in the first place. Worn tires and high speed in heavy rain are a recipe for desaster.

Since you mentioned cold weather, snow and ice, I'm not sure if you're really asking about hydroplaning though since those are not factors when it comes to hydroplaning.

 

[PhilDavid]

I was just looking for best practices because I recently saw a video of a Model 3 hydroplaning so wanted to commit a set of actions to memory. You can;t always avoid this situation based on the water volume and saturation of the road.

Seems the best thing to do is to reduce acceleration to "zero" so you are neither accelerating nor causing regen and use only light steering input towards where you want the car to go with no abrupt turns of the wheel or major over-corrections.

So the question is the car's traction control system should surely be able to tell that the car is hydroplaning - right? Should or does the traction control system automatically engage zero acceleration and no regen if your car starts slipping and sliding on water or ice?

 

[Geek190]

For what it's worth, and your mileage may vary, and my experience only, and others have different opinions.....

I've hydroplaned plenty of times, but not in my S yet. My instant and immediate response has always been to let go of the gas but not to apply brakes. Seems to me that just the act of hydroplaning slows the vehicle rather quickly. There has to be a fair amount of water on the road, and it acts just like applying the brakes.
In every instance so far (just for me) I have regained control in just a few seconds as the car slows down. I wouldn't be so concerned about slowly and carefully easing up on the throttle to limit regen. Just keep steering where you want to go and let the water and regen slow you down.

Snow and ice are completely different animals. Throttle and brake manipulation are of utmost importance in snow and ice. Calm, steady, slow and deliberate. Practicing "drifting" in a large parking lot is the best way to learn how to control the car on snow and ice.

 

[David29]

I was just looking for best practices because I recently saw a video of a Model 3 hydroplaning so wanted to commit a set of actions to memory. You can;t always avoid this situation based on the water volume and saturation of the road.

Seems the best thing to do is to reduce acceleration to "zero" so you are neither accelerating nor causing regen and use only light steering input towards where you want the car to go with no abrupt turns of the wheel or major over-corrections.

So the question is the car's traction control system should surely be able to tell that the car is hydroplaning - right? Should or does the traction control system automatically engage zero acceleration and no regen if your car starts slipping and sliding on water or ice?

Good questions! I took skid control courses many years ago, where we were shown how to deal with this in the days before anti-lock brakes. I remember going to a second skid school just after Mercedes introduced the anti-lock brakes, in the mid-a980s I think, and the instructor was frustrated because he could not lock up my friend's S class coupe.

Anyway, I think the ABS is the key. You can use the brakes to reduce speed to the point where the tires regain their grip.

Here is what the Model S owner's manual says:

"Model S has an anti-lock braking system (ABS)
that prevents the wheels from locking when
you apply maximum brake pressure. This
improves steering control during heavy
braking in most road conditions.
During emergency braking conditions, the
ABS constantly monitors the speed of each
wheel and varies the brake pressure according
to the grip available.
The alteration of brake pressure can be felt as
a pulsing sensation through the brake pedal.
This demonstrates that the ABS is operating
and is not a cause for concern. Keep firm and
steady pressure on the brake pedal while
experiencing the pulsing."

 

[ucmndd]

Model S is just a car. There’s not really anything to do differently than any other car.

The only real rule with hydroplaning is no abrupt lateral or longitudinal inputs. Let the car generally maintain its current course and speed until you regain traction.

Even if you panic and lift the accelerator, if regen causes the wheels to lock the ABS is going to kick in nearly instantaneously and kill the regen completely.

 

[PhilDavid]

Model S is just a car. There’s not really anything to do differently than any other car.

The only real rule with hydroplaning is no abrupt lateral or longitudinal inputs. Let the car generally maintain its current course and speed until you regain traction.

Even if you panic and lift the accelerator, if regen causes the wheels to lock the ABS is going to kick in nearly instantaneously and kill the regen completely.

Could you confirm that the system is designed such that if the car starts slipping and sliding, the software will disable regen (as it probably should)?

I guess if you are driving through crazy torrential rain and snow/ice conditions, is it best to turn off regen?

 

[Geek190]

For snow and ice I would turn off the regen. Up to you on the heavy rain, but I wouldn't worry about it.

 

[ucmndd]

Could you confirm that the system is designed such that if the car starts slipping and sliding, the software will disable regen (as it probably should)?

This is certainly my personal experience. The ABS system immediately cuts regen. Hit a bump while decelerating on a slick off ramp, stuff like that - if you’re not paying attention it feels like the brakes aren’t working at all and you’re not gonna stop.

 

[PhilDavid]

For snow and ice I would turn off the regen. Up to you on the heavy rain, but I wouldn't worry about it.

I wish there was some way to automate this...

 

[X-pilot]

Steer in the direction you intent go (hopefully no large changes), decelerate slowly/moderately until regaining control. There are suggestions that cruise control NOT be used, as it could tell the car to add power to the slower rotating wheel(s) (i.e., floating on the water) and cause stability issues. There is formula for hydroplane speeds, which is 9 times the square root of the tire pressure.

Hydroplane speeds for vehicles

 

[croman]

Model S is a miracle car but don't go looking for miracles.

It's literally the best car for almost any situation except narrow areas and agile turns.

 

[DCEV]

Steer in the direction you intent go (hopefully no large changes), decelerate slowly/moderately until regaining control. There are suggestions that cruise control NOT be used, as it could tell the car to add power to the slower rotating wheel(s) (i.e., floating on the water) and cause stability issues. There is formula for hydroplane speeds, which is 9 times the square root of the tire pressure.

Hydroplane speeds for vehicles

So glad this thread made me think of what to be prepared for. Thanks @PhilDavid for bringing this up.

So is it better to not use Autopilot in snow/ice or other tricky traction conditions?

 

[croman]

For snow and ice tires make the biggest difference. Get the best snow tires. I've got Michelin X Ice3 and they are awesome. Never let me down and I've driven in insane conditions for both snow and ice (and combined).

 

[croman]

So glad this thread made me think of what to be prepared for. Thanks @PhilDavid for bringing this up.

So is it better to not use Autopilot in snow/ice or other tricky traction conditions?

I don't often use AP in bad conditions even if it's available because I need to have a feel for the road and car and AP separates you from that until it is too late.
Remember in snow the radar often ices over if the snow is wet or salt is there to partially melt the snow
Even heavy rain or truck spray disables radar.

Don't rely on AP because it will give you little warning and then disable itself.

 

[DCEV]

Model S is a miracle car but don't go looking for miracles.

It's literally the best car for almost any situation except narrow areas and agile turns.

Yup. absolute perfection until you are in a tight parking garage with curbs and island everywhere along with super narrow ramps with curbs and you have no 360 view.

What a shame they didn't include 360 view for such a wide car

 

[DCEV]

For snow and ice tires make the biggest difference. Get the best snow tires. I've got Michelin X Ice3 and they are awesome. Never let me down and I've driven in insane conditions for both snow and ice (and combined).

The thing is that snow tires are not practical for most of us who live in parts of the country with relatively moderate winter weather.

This is the reason I replaced my Pilot Sport summer performance tires with Pilots Sport A/S 3+ tires to get at least a bit more benefit in the winter than the summer performance tires.

 

[croman]

The thing is that snow tires are not practical for most of us who live in parts of the country with relatively moderate winter weather.

This is the reason I replaced my Pilot Sport summer performance tires with Pilots Sport A/S 3+ tires to get at least a bit more benefit in the winter than the summer performance tires.

If you don't need the tires the Model S traction control is the best there is. All EVs are so much better than ICE but Tesla is creme de la creme.