TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

P85D vs Horrid Winter Slush

Discussion in 'Model S: Driving Dynamics' started by Dbitter1, Jan 3, 2015.

  1. Dbitter1

    Dbitter1 Journeyman Member

    Joined:
    Dec 12, 2014
    Messages:
    201
    Location:
    Chicago, IL
    Wanted to share my experience, on the first day of truly crappy ~30F weather, with slush, sleet, ice, black ice, snow, and otherwise miserable potluck winter weather. Y'know, the kind that you REALLY want a AWD vehicle to drive in.

    In a nutshell: my Tesla did everything I expected it to do... it performed at least as well - if not better- than my former Audi Quattro on a miserable mix of poor friction roads. The ABS worked very nicely when stomping hard on the brakes, to bring the car to a controlled stop; the car accelerated smoothly under low and medium power with no noticeable slip (e.g any lasting longer than a few milliseconds) . Did not do a hard Launch just for safety sake, but given a proper area or need, the car certainly would have tried. Bravo, Tesla, bravo. I have an all year car electric car now!

    This was with the standard all-weather tires on 19" rims. I assume it would be even better with specialized winter tires*... our first 4"+ snowfall is supposed to come next week, so will test it under heavy snow load then.

    Which brings up an interesting question... if I raise the car (via air suspsension) for some reason (e.g. to get out of my alley without bottoming out the car) is there some way to get it to "forget" the event so it doesn't always try to do it again each time?

    Also: despite previous reservations, the "stock" all-weather floor mats (the lesser grade WeatherTech ones sold from Tesla directly) seemed to contain the mess from shoes nicely.

    Also: didn't know there was a UPPER limit on discharge on the battery when cold, too... just thought it limited regen braking, but it also limited accelleration too... was around ~ 300KW IIRC, and disappeared a lot quicker than the regen limit did as the car warmed.

    *Did not feel the need to drain my wallet further for a special tire set. It does not snow THAT much in Chicago... or at least not without Snowmageddon happening.
     
  2. commasign

    commasign Active Member

    Joined:
    Aug 31, 2013
    Messages:
    1,058
    Location:
    Davis, CA
    Yes, look for a little button to pop up at the top of the air suspension section of the interface allowing you to delete the auto-raising feature for that location. Unfortunately there's no way to delete this globally or for other locations. You sort of have to go back to each location to delete the flag.
     
  3. Barry

    Barry Member

    Joined:
    Aug 9, 2013
    Messages:
    785
    Location:
    Colorado
    The the car beep at you when "traction control" (or the Tesla equivalent of detecting and correcting wheels not spinning at the same rate) comes on?
     
  4. onasj

    onasj Member

    Joined:
    Dec 30, 2014
    Messages:
    23
    Location:
    Boston, MA
    P85D, 19" winter tire package, horrible driving conditions tonight: several inches of fresh snow that turned to slush on the mostly unplowed roads and highways (weather forecast was much better than this!). I was blown away by the performance of the car under these conditions. About 30+ miles of mixed highway and suburban roads, ZERO tire slippage, ZERO traction control warning, ZERO brake solenoid (ABS starting). Passed several multi-car wrecks on the drive. Honestly I can't give a better score for its performance tonight. 100/100.
     
  5. kevincwelch

    kevincwelch Active Member

    Joined:
    May 13, 2012
    Messages:
    2,016
    Location:
    Chicagoland
    It's nights like these I wonder if a front wheel or AWD car would have done me better.

    I went through the winter of 2013 with the OEM Goodyears and had a lot of traction control warnings. I went through the winter of 2014 with my Michelin Xi3s with good success. Tonight, the car couldn't handle the ice unfortunately. We had a small snowfall last night (<1/2 inch) and then it rained all day. By the late evening, there was ice on a lot of the roads. I was driving slowly (10-15 mph) and coming to a slow stop (basically my regen engaging -- wonder if low regen is better for these situations), and then it happened. About a 120 degree spin to a stop. Came close to the curb, but luckily didn't hit it. Took a 90-degree turn and then stopped at a friend's house to pick up my daughter. I headed out of the cul-de-sac and then back on to the street. One block later I came to another stop: 90-degree spin. Both spots with ice -- smooth but irregularly shaped as I later inspected.

    Last time this happened was about 15 years ago. Hopefully just some bad patches of ice.
     
  6. Cerie

    Cerie Member

    Joined:
    Sep 6, 2014
    Messages:
    105
    Location:
    Connecticut
    I was out in Boston today as well right when the snow started and by the time I had come back to CT, there was maybe an inch or so of unplowed fresh snow. I have the S85, no winter tires and except for one turn where it pulled at the end, it didn't feel any different than last winter in my Camry Hybrid. At this rate, I might not even get the snow tires.
     
  7. Bighorn

    Bighorn Member

    Joined:
    Jun 19, 2013
    Messages:
    483
    Location:
    WY
    Icy roads demand low regen. Loss of rear traction very dangerous and unwieldy with full regen on.
     
  8. kevincwelch

    kevincwelch Active Member

    Joined:
    May 13, 2012
    Messages:
    2,016
    Location:
    Chicagoland
    Yup.

    Guess I was lucky in the past two years. Important lesson. I switched it after those two spins but didn't encounter any significant ice for the remainder of the drive. We'll see tomorrow; I doubt the village sends any salt trucks out tonight.
     
  9. Dbitter1

    Dbitter1 Journeyman Member

    Joined:
    Dec 12, 2014
    Messages:
    201
    Location:
    Chicago, IL
    Black ice will kill anyone. Any vehicle*. The manufacturer that figures out how to warn drivers of same in enough time to take corrective action proactively... will be a very rich one. And probably win some kind of prize for humanity. Don't feel bad. Be glad you handled it and no damage!

    * I suppose if you have tire chains and/or cat tread, you have a decent fighting chance.
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
  11. bstronger

    bstronger Member

    Joined:
    Feb 3, 2010
    Messages:
    7
    Icy roads demand low regen.

    I am repeating this for emphasis. Any force at the wheels starting or stopping has to be controlled
    very precisely on ice. Even traction control hunting for traction between wheels can cause a breakaway.
    In extemis if a spin starts you are often better off shifting to neutral to take force of all wheels to come out
    of the spin. I suspect most far north drivers know this. Brian
     
  12. Jaff

    Jaff Active Member

    Joined:
    Aug 15, 2010
    Messages:
    3,007
    Location:
    Grimsby, Canada
    I would echo your comments completely...we picked up our P85D (Maxx) yesterday from the Toronto store...on the ride home, we encountered freezing rain, ice, snow and rain... Maxx, wearing the 19" Nokia handled the journey flawlessly!

     
  13. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Joined:
    Feb 27, 2009
    Messages:
    5,062
    Location:
    Colorado
    It appears that the regen in the P85D does this automagically. In the few times that I have been in downhill, full regen mode, and the traction has gotten iffy, the P85D disabled regen completely until traction was regained solidly. I like the P85D automagical operation here!
     
  14. Dbitter1

    Dbitter1 Journeyman Member

    Joined:
    Dec 12, 2014
    Messages:
    201
    Location:
    Chicago, IL
    Agreed... it seems to have this part figured out.

    **HOWEVER** day two of crappy weather, and the mix of [already] horrid weekend traffic and weather, and today's experience is a little different. The traction control remains unparalleled, and at all times on several hours of errands today I felt totally safe.

    That said, driving down a nice open street, with a little snow on it and a light snowfall, steady at ~30MPH, all of a sudden I got a bit "STOP!" from the front park assist, like it saw a ghost... then shortly after the computer disabled parking assist for me. No worries, kept driving, didn't try to adjust my speed or anything, but marginally unnerving if Elon & crew aren't testing autopilot in something other than sunny California what it would have done. Pulled into first store, parked, came out, then the front camera was apparently disabled, with appropriate complaint on dash. Next store, back to both camera and park assist disabled notifications. Looked at camera, only a little slush, but oh well, no big deal. I'll stay in full control in this weather anyway, thank you.

    Complaint number two: although I don't expect the car to defy the laws of physics, with the heat, almost no regen brake, and slow-a*s Chitown city traffic, I was at ~830 on the old watt-mile average! :scared:
     
  15. Bighorn

    Bighorn Member

    Joined:
    Jun 19, 2013
    Messages:
    483
    Location:
    WY
    Good to hear your early impression that this issue may have been sorted. Was very mindful of this driving on glare ice just now. With Mu headed toward zero, the P85+ can't tolerate more than 30kW of regen without giving up the rear end.
     
  16. evp

    evp Nerd

    Joined:
    Nov 28, 2014
    Messages:
    295
    Location:
    Arvada, CO
    Yeah, I discovered quickly that traction control in the 2WD Tesla isn't as skillful in deceleration as in acceleration. I'll turn down regen the next time it gets really slippery.

    I had an experience driving into Oregon last winter. Driving along on the Interstate at 70mph, I saw a nice snow-covered scene I wanted to photograph, so I braked to pull over to the shoulder. And discovered when the ABS started chattering that it wasn't snow covered -- it was ice-covered, as was the road. Looked totally dry. Now I know what black ice is. It scared me on a very fundamental level to see all the semi trucks blithely cruising by at 70 unaware of their peril.
    DSC_6040.JPG
     
  17. Bighorn

    Bighorn Member

    Joined:
    Jun 19, 2013
    Messages:
    483
    Location:
    WY
    Rime and reason:)
     
  18. yoyo

    yoyo Member

    Joined:
    Nov 14, 2014
    Messages:
    103
    Location:
    IL, USA
    yeah, the P85D handled these two days of ice and slush nicely. Did not feel any traction issue at all, and it was able to accelerate smoothly, (and saw several accidents). The heated windshield was great - ice formed on it after mere 10 minutes in parking lot, but was able to thaw them off after about 5 minutes of windshield heating...
     
  19. kevincwelch

    kevincwelch Active Member

    Joined:
    May 13, 2012
    Messages:
    2,016
    Location:
    Chicagoland
    The S with winter tires handles snow and slush nicely. I suppose that's why black ice is such a unnerving thing: it's hard to see it coming.
     
  20. RDoc

    RDoc S85D

    Joined:
    Aug 24, 2012
    Messages:
    1,569
    Location:
    Boston North Shore
    Rover had such a system, the Icelert in the 70's. It was an infrared sensor that warned if the road ahead was below freezing so if you saw something that looked like water and the alert was on you knew it was ice.
     

Share This Page