Hydroplane and lifting off the accelerator

[Broccoli2]

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.

What exactly is your issue.... There are many causes and types of oversteer. Do you have any formal driving experience? "Lift-off Oversteer" is common on front wheel drive cars. This happens when you enter a corner too fast and "Lift" as you hit the apex you will lose traction of the rear tires causing oversteer. and the correct thing to do is add throttle. This is NOT the case in what happened with me. Teslas weight is centralized and I was not hitting the apex of a corner too fast. In most cases the ideal cornering technique in a performance car is to try and reduce power to control oversteer.
As far a driving a Skidcar... I have slid cars at over 100mph 2 feet from Hundreds of thousands of dollars worth of camera gear and not once did I hit one or anyone.

If you tell me I am wrong any further, you will be ignored as apparently you have a degree in "Google car handling technics". Ps. Go take your model 3 on a track, get yourself into an oversteer situation (NOT "lift-oversteer") and give it a bunch of throttle and report back.

 

[ulrichw]

What exactly is your issue.... There are many causes and types of oversteer. Do you have any formal driving experience?

3 years SCCA regional racing, about 5 years track days. About 2 years trackdays on motorcycle.

If you feel that lifting is the right thing to do when suddenly faced with oversteer (in any car), more power to you.

Edit: That experience doesn't make me an expert, but I do feel I'm knowledgeable.

 

[Niroc]

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.

The thin layer of oil on the road and recent rain storm can cause a lot of havoc especially in places where it doesn't rain much.

I live in the Northwest and I drive a rwd Mustang. The car is basically a sled in bad weather conditions. I just ordered a sr + rwd. You don’t need awd in the NW. just a tad bit of caution is warranted on those heavy rainy days. And I like the idea of having a “Rain” profile. That is a great tip.

 

[SammichLover]

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

Stay frosty. <edit, for clarity> Very slowly ease off the throttle.

Definitely wouldn't lift all the way off as my immediate response. If you are hydroplaning you're putting a lot of energy into moving water out of the way, which will slow you of course, and the more you slow the more that water is going to slow you as you drop back down into it towards the pavement underneath.

 

[SammichLover]

AWD Tesla would be in better control in the same situation.

Yes.

Top were the rears (dead, Jim), bottom on the front (at about 2/32"), and the bottom left foreground was someone else's problem.



Had to adjust top speed, because obviously braking distance is impacted, but the ability for the front to keep/bring the vehicle on track in heavy rain water and even thin layers of slimy mud over pavement (spillage from dump trucks pulling out from a clay source) was very impressive given what it was working with.

P.S. That said I would not recommend doing this at home, kids. These should have been changed out earlier.

 

[shplatt]

I live in the Northwest and I drive a rwd Mustang. The car is basically a sled in bad weather conditions. I just ordered a sr + rwd.

I'm with you on that one. I've been driving a 2017 Mustang GT the past 2.5 years. The thing does NOT like wet roads - and I live in the Sacramento area where the rain is nothing like the NW. My natural response has always been neutral to slight lift on the throttle and light steer into the skid. That's kept me on the road and away from paint-swaps, but doesn't keep my heart from wrapping itself around my throat. I've long trained myself not to put in sudden, extreme inputs unless warranted. Still, the one time it broke free on a wet clover leaf freeway interchange, with my daughter on board and the top down, was enough to reevaluate whether it's worth keeping the thing. So, I just ordered a Model 3 Perf two days ago.

 

[Niroc]

I'm with you on that one. I've been driving a 2017 Mustang GT the past 2.5 years. The thing does NOT like wet roads - and I live in the Sacramento area where the rain is nothing like the NW. My natural response has always been neutral to slight lift on the throttle and light steer into the skid. That's kept me on the road and away from paint-swaps, but doesn't keep my heart from wrapping itself around my throat. I've long trained myself not to put in sudden, extreme inputs unless warranted. Still, the one time it broke free on a wet clover leaf freeway interchange, with my daughter on board and the top down, was enough to reevaluate whether it's worth keeping the thing. So, I just ordered a Model 3 Perf two days ago.

Nice! My 2011 GT convertible is sold. My delivery is coming this Thursday. I will miss the convertible but too many cool things on the M3 to worry about that.

When you pull up next to BMW M3 or Camaro ss, blow em a kiss and piss them off. Then, smoke them off the line with the Perf and let them eat electrons

 

[shplatt]

Nice! My 2011 GT convertible is sold. My delivery is coming this Thursday. I will miss the convertible but too many cool things on the M3 to worry about that.

When you pull up next to BMW M3 or Camaro ss, blow em a kiss and piss them off. Then, smoke them off the line with the Perf and let them eat electrons

Heheh... "Eat my gauss."

 

[David99]

Similar problems have been the topic of discussions here several times. 5 years of driving in my Model S, I have been in similar situations a few times. When the road gets slippery and the cars starts to slide, the natural reaction of every driver is to lift off the accelerator. It is an automatic reaction. It is almost impossible to suppress. In a Tesla, regen kicks in and creates negative torque which can be too much and causing the car to slide even more. Especially on icy roads regen kicking in can make things much worse. I have been in this situation myself and it was scary. Going sideways on a freeway is no fun! Unfortunately neither traction control not stability control acts the same way on regen as it does on acceleration. Traction control will keep my car almost like on rails even in difficult situations when accelerating. But once I let go of the pedal, regen kicks in unfiltered.

On icy/slippery roads, disabling regen would be the best choice. When the car starts to slide, the best thing you can do to gain stability is to have zero torque on the wheels. Just have them free rolling. Any torque is an additional force that makes the wheel lose grip. To deal with these situations I have literally trained myself to keep on hand on the stalk to switch to neutral quickly. It's the only way to disable regen. Trying to feather the accelerator to be coasting is virtually impossible. The best solution would be for Tesla to have traction control works properly with regen.

 

[Bill Foster]

Sounds like you need to more HPDE

 

[Uncle Paul]

When in an oversteer (rear tires loosing grip) you need to increase throttle to transfer weight off the front and onto the rears.

If you are in wet conditions, and your tires have not enought tread to displace the water then adding throttle will not have enough traction to transfer the weight. Driver is doomed due to the lack of tire tread and a spin in inevidible in a cornering situation.

Driver must know his vehicles capabilities and keep it in top condition if venturing forth on either a track competition or on a water soaked public road.

Not the time to blame the car. In most states those tires would not be legal for use on public roads. There are tread depth regulations for a reason. OP found the reason.

 

[SammichLover]

When in an oversteer (rear tires loosing grip) you need to increase throttle to transfer weight off the front and onto the rears.

If you are in wet conditions, and your tires have not enought tread to displace the water then adding throttle will not have enough traction to transfer the weight. Driver is doomed due to the lack of tire tread and a spin in inevidible in a cornering situation.

Once they got into oversteer, yes. I don't think they were in oversteer to start with, unless I misread it? Rule of thumb is whether or not you can make a situation better, you can always make it worse.

My suggestion about "stay frosty" assumes you aren't threated with imminent demise if you don't change something. Small, gentle changes, if any at all, and patience until things sort out and you get to a position of having some more friction to work with. If you've gotten up on the water you can't slow as quick but you WILL slow down as a natural course. Lifting full off is neither small nor gentle, especially in a manual transmission or something with active regen.

In an imminent demise situation, yeah you're kinda doomed. Your mistake, and the potential to branch away to a safe spot, was further back in time. Now it is just about making small changes to make the doom a bit more acceptable...stay frosty still applies. Perhaps if only for you to make peace with your entry to the afterlife. :/

P.S. Theoretically your RWD vehicle will do a small amount of weight transfer to the rear even if you're spinning your tires, even in a frictionless environment the, due to vehicle mass rotating opposite direction (as per "equal and opposite reaction"). But the spinning wheels aren't going to pick up much friction due to spinning, being in kinetic friction rather than static friction mode.

 

[Feathermerchan]

First real hydroplane experience was with a 1977 VW Scirocco (FWD manual trans). Had cruise control on and fwy had worn trails in the lanes so deeper water than elsewhere. Engine revved and I noticed speedometer jumped about 10 mph and car got a little squirrely.. Kicked off cruise and let tires regrip and all was good. Scary though.

So I thought, on a RWD car the front tires should hydroplane first because the rear tires generally follow the fronts and the fronts move a lot of water out of the way making it easier for the rears to grip. When the fronts are hydroplaning on a straight flat stretch of road it may be barely noticeable until you need to turn or brake. But if the rears hydroplane then it is probable that all four tires are hydroplaning. If the rear steps out into undisturbed (deeper) water and the rear tires were already hydroplaning, the situation is not going to get better. I could see the car being uncontrollable.

 

[wonky]

[apologies if it is poor form to resurrect an old thread]
This just happened to me this week, full spin out and hit concrete barrier on highway twice. Model 3 (2018 long-range, RWD) is probably totaled, waiting to hear back from insurance. On one hand, I only got neck pain and a concussion, and it was a serious wreck. On the other hand, I was baffled by how the car handled, one sec it was fine and the next I was in a spin, no warning. Going 45-50 on 70 speed limit road, it had been raining all morning.

I wish I had heard about turning the regen to low during rain, I suspect that had a hand in it. Was there really anything I could have done to control the car? It did not appear so to me, but I can see that if I fully lifted my foot off the accelerator upon sensing a loss of traction, that made it way worse than it otherwise would have. Seems very simple for Tesla to auto Chill regen when wipers are on!

I really can't decide whether to get a new 3 (AWD this time) and add a Rain profile, or if I will just always be in fear of it recurring.

 

[jjrandorin]

[apologies if it is poor form to resurrect an old thread]
This just happened to me this week, full spin out and hit concrete barrier on highway twice. Model 3 (2018 long-range, RWD) is probably totaled, waiting to hear back from insurance. On one hand, I only got neck pain and a concussion, and it was a serious wreck. On the other hand, I was baffled by how the car handled, one sec it was fine and the next I was in a spin, no warning. Going 45-50 on 70 speed limit road, it had been raining all morning.

I wish I had heard about turning the regen to low during rain, I suspect that had a hand in it. Was there really anything I could have done to control the car? It did not appear so to me, but I can see that if I fully lifted my foot off the accelerator upon sensing a loss of traction, that made it way worse than it otherwise would have. Seems very simple for Tesla to auto Chill regen when wipers are on!

I really can't decide whether to get a new 3 (AWD this time) and add a Rain profile, or if I will just always be in fear of it recurring.

If you "hit a concrete barrier doing 45-50 MPH, and "only have neck pain and a concussion" (and are ok enough to be searching the internet and looking at forums), then I would say that the car protected you VERY well. Not trying to make light of an accident, but an accident at 50MPH hitting concrete, and you just have "neck pain and a concussion" is one of the biggest endorsements I can think of for you to get another one of the same type cars....

 

[Phlier]

Not trying to make light of an accident, but an accident at 50MPH hitting concrete, and you just have "neck pain and a concussion" is one of the biggest endorsements I can think of for you to get another one of the same type cars....

This. ^

Traction control is a wonderful thing, but as wonderful as it is, it still can't overcome the laws of physics. You should also take into consideration that the traction control system very likely lessened how severe the outcome otherwise would have been. There's a bit of supposition on my part by saying that, as I'm not privy to exactly what happened, but a lot of accident outcomes are better with vehicles that have a traction control system in them than without.

You got into an accident in the highest safety rated vehicle on the road, hitting a concrete barrier at 50 MPH and walking away with a concussion and some soreness. Wonder what the outcome would've been if you'd been in the fifth highest rated vehicle.

If I were in your shoes, I'd have an open browser tab on Tesla's site right now, ordering a new car.

Glad you're not seriously hurt, man.

 

[Rottenapplr]

This. ^

Traction control is a wonderful thing, but as wonderful as it is, it still can't overcome the laws of physics. You should also take into consideration that the traction control system very likely lessened how severe the outcome otherwise would have been. There's a bit of supposition on my part by saying that, as I'm not privy to exactly what happened, but a lot of accident outcomes are better with vehicles that have a traction control system in them than without.

You got into an accident in the highest safety rated vehicle on the road, hitting a concrete barrier at 50 MPH and walking away with a concussion and some soreness. Wonder what the outcome would've been if you'd been in the fifth highest rated vehicle.

If I were in your shoes, I'd have an open browser tab on Tesla's site right now, ordering a new car.

Glad you're not seriously hurt, man.

Was the accident a head on crash into a barrier?

 

[wonky]

The first hit was at ~45 degree angle on the rear left bumper edge, second was head-on but it had lost some momentum by then. No airbags deployed. The car protected me very well, there's no question in my mind that it was the best possible outcome. But I can't help but think it may not have happened at all if not for the regen response on a RWD in slippery conditions.

 

[SMAlset]

@Broccoli2 , just came to thread and videos aren’t available. Any chance you can fix? Getting Video Unavailable.

 

[CrayZ1]

Hydroplaning is caused by speed. A foot of water can be crossed at low speed. 3" of water can be crossed at maybe 20 mph. 1" of water at 55 mph can force the tires to lose contact with the ground. Ever been water-skiing? That. Even a 5000lb car can lose contact with the ground with just a 1/2" of water when you're going fast enough.

If you lock up the rear tires in a RWD car you can still steer. Take a car with a hand brake, get going 45 mph and pull up HARD. See?
However, hydroplaning hits the fronts the hardest, because they 'plow' a path for the rears. It lifts them off the road, and lets the car rotate (yaw) about it's CG.