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

Vulnerable to crosswinds on highway? NOT!

Discussion in 'Model S: Driving Dynamics' started by kinddog, Mar 5, 2013.

  1. kinddog

    kinddog Banned

    Joined:
    Oct 8, 2012
    Messages:
    564
    Location:
    Northern Virginia
    Edmunds' long-term test on the Model S recently included the following statement:

    "We got back on the road and soon realized how much the Model S does not like crosswinds. For several miles, keeping the sedan true in the lane was difficult. Nothing severe, but not the kind of dynamic flaw you find in a Mercedes S Class or a Porsche Panamera."

    What a bunch of MALARKEY! Just think about it... Model S has the lowest coefficient of drag of any car in existence. So scientifically speaking, it should be the LEAST affected by crosswinds. Further, it's a very HEAVY car at what 4,600lbs plus my fat-@$$ (i'm not really fat, just big boned and a lot of muscle, which weighs more than fat. a little babyfat around the middle, but i was heavy as a kid and, um--). So that's another factor in favor of this car not being affected by crosswinds. 50/50 weight distribution, a comparatively long wheelbase, and i think this Edmunds criticism is completely fabricated. OR he was driving thru like Hurricane Sandy, and NO CAR would have performed better (Panamera and S-class included).

    It's almost like journalists have to make things up out of thin air that are negative about the Model S, because they think it lends more journalistic integrity than if they just fawned over the car 100% (as in reality the probably do). p*sses me off.


    Anyway, question is, have YOU noticed any instability on the highway with strong crosswinds?
     
  2. doug

    doug Administrator / Head Moderator

    Joined:
    Nov 28, 2006
    Messages:
    15,913
    Location:
    Stanford, California
    Hmm... a low Cd, which is measured for airflow head on does not necessarily mean there will be low drag for flow coming from the side. That said, I don't think I've ever seen published side drag figures for cars. Would be interesting to compare.
     
  3. grisnjam

    grisnjam P6316

    Joined:
    Dec 29, 2011
    Messages:
    247
    Location:
    Austin, Texas
    I have noticed a lot more sensitivity to side winds on the freeway in my Model S then my Audi A3 (the small hatchback) but I figured it was just do to the much larger Model S having more cross section for the wind to act on. How it would compare to a car of the same shape, I don't really know.
     
  4. dave

    dave Member

    Joined:
    Sep 21, 2012
    Messages:
    451
    Location:
    Greater Cincinnati
    Yeah, the drag numbers are all about going forward. I doubt anyone tests SIDEWAYS drag numbers! Obviously tall vehicles like vans and trucks etc would be more affected by cross winds. You'd think the Model S, with it being so low wouldn't be affected very much.

    That being said I actually have noticed a couple times where the car was pushing to the right or left, and I chalked it up to crosswinds. I really can't say if it is better or worse than any other car though.
     
  5. nleggatt

    nleggatt Member

    Joined:
    Dec 7, 2011
    Messages:
    389
    Location:
    Abbotsford, BC
    Ok, maybe I'm jumping into the fire here, BUT, the car is pushed around a-lot by cross winds. Sorry, but it's true. I was driving past a semi the other day and when I came out the other side the wind hit me sideways and pushed me big time. Then the other day I was driving down the hwy again and a cross wind across the flats by my place hit me and it really pushed the car around. Maybe its a the size of the car versus what I've drive in the past, but either way, it was noticeable. Now, it's not a reason to not like the car, but you should be aware of it.
     
  6. Krugerrand

    Krugerrand Active Member

    Joined:
    Jul 13, 2012
    Messages:
    4,255
    Location:
    California
    I can not comment to your question, but I just wanted to give you a *hug* and let you know that fat people deserve loving too. Err...I mean big-boned people with a lot of muscle, which weighs more than fat, and a little baby fat around the middle, even if they were heavy as a kid, but aren't now....) *Another hug just because*
     
  7. JRP3

    JRP3 Hyperactive Member

    Joined:
    Aug 20, 2007
    Messages:
    10,098
    Location:
    Central New York
    Get a room.
     
  8. sp4rk

    sp4rk Banned

    Joined:
    Apr 25, 2012
    Messages:
    1,219
    Location:
    Schaumburg, IL
    Pity you two live so far apart ... a reason to have an annual convention? :rolleyes:
     
  9. AnOutsider

    AnOutsider S532 # XS27

    Joined:
    Apr 3, 2009
    Messages:
    11,923
    What this guy said. Not everything is a scheme to discredit Tesla. I know I've personally experienced high crosswinds making the car feel a bit unstable, and it's been posted on these forums by others.
     
  10. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,848
    Location:
    Ottawa, Canada
    I can also confirm that it does blow around in crosswinds more than some vehicles. A friend of mine has observed that it seems to be less stable in a crosswind if you are using the cruise control. I haven't had a chance to verify that for myself.
     
  11. mai

    mai Member

    Joined:
    Dec 6, 2012
    Messages:
    35
    Location:
    San Jose, CA
    I wonder if the low air suspension setting at high speeds makes it more susceptible to pushing....
     
  12. Krugerrand

    Krugerrand Active Member

    Joined:
    Jul 13, 2012
    Messages:
    4,255
    Location:
    California
    Cat person. :biggrin:
     
  13. Quibbs

    Quibbs Member

    Joined:
    Jan 13, 2013
    Messages:
    64
    Location:
    Southeast US
    I have not received my car yet. However, I have a theory, probably incorrect, but hey, why not.....I think electric power steering may have an impact, just like the size of the car does. My old Porsche 997 had hydraulic steering and always seemed planted to the road, even in fairly strong crosswinds. I replaced that car with a new Porsche 991, which is longer and more aerodynamic I believe. Theoretically the 991 should be as solid, in the same situation. In my travels so far, it is quite the opposite. My new 911 seems to be much more sensitive to the crosswinds. The 991 is easily pushed around, making it difficult to keep centered in a lane. My wife has a new Cayenne, hydraulic steering, but a tall vehicle. Stable in cross winds.Even a Panamera we had for a bit was pretty solid in these winds. Just like my BMW 335i (hydraulic)..... I may be completely wrong, but I do think the new EPS systems could be vulnerable to side winds (lag time, not tuned for this condition??). Like I said, just a theory of mine.

    I was disappointed to read that this is indeed the case, especially in a car this big. Now of course it does not matter. The check was sent today, papers signed, deal is done, in for a penny, in for 100k at this point.
     
  14. JRP3

    JRP3 Hyperactive Member

    Joined:
    Aug 20, 2007
    Messages:
    10,098
    Location:
    Central New York
    Or does the smooth under body and the shape of the upper body generate some lift, like an airplane wing, allowing cross winds to push it more?
     
  15. Al Sherman

    Al Sherman It's about THIS car.

    Joined:
    Nov 29, 2012
    Messages:
    1,692
    Location:
    Batesville, IN
    K that's it! I'm cancelling my subscription to Edmunds. Deal Breaker. Oh wait, do I HAVE a subscription to Edmunds. No.

    Disclaimer: I AM big boned. I truly am. I also eat a lot more than the rest of you and I'm fat.
     
  16. Bearman

    Bearman Member

    Joined:
    Nov 17, 2011
    Messages:
    363
    Location:
    Sweden
    From what I understand it can be pretty difficult to know what exactly makes different cars feel more sensitive to crosswinds than others so take any general ideas with a grain of salt. There seems to be some truth to the idea that the type of steering can influence negative dynamics of the car in crosswinds, in one research article[1] those drivers who just went along and didn't over-correct ended up moving the car around less. So electrical power steering might be too direct for some drivers and increase the cars movements to the sides especially since the crosswinds usually come in unpredictable short bursts. This could be tested by changing the steering response in the Model S to a less sensitive setting on the touchscreen. The general consensus is that cars with low coefficients of drag are more sensitive to crosswinds because of their asymmetric side surface area but apparently a "Kamm rear end" (Prius) mitigates this.

    Screenshot_16.jpg

    However why a car is more or less stable in heavy crosswinds is answered by the fundamental properties of the car: Center of mass, Center of steering forces, Aerodynamic center of pressure, Tires, etc.
    Screenshot_14.jpg
    Screenshot_15.jpg

    Here is the link to the full [1]article.
     
  17. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Yeah. It'll take crosswinds over that ugly stuffed-rat-with-4-wheels Prius look, please.
     
  18. Al Sherman

    Al Sherman It's about THIS car.

    Joined:
    Nov 29, 2012
    Messages:
    1,692
    Location:
    Batesville, IN
    LOL. Hey, I really like my little stuffed rat!
     
  19. RDoc

    RDoc S85D

    Joined:
    Aug 24, 2012
    Messages:
    1,569
    Location:
    Boston North Shore
    Well, yet again Citroen had some good ideas with the DS series. It had active hydraulically augmented steering set up so that at higher speeed there was a small range of steering which was less sensitive so you could make precise corrections with less tendency to over correct. At lower speed and outside that range it was normal. The effect was that staying within a lane at highway speed used the less sensitive area. I never noticed any particular cross wind sensitivity but the car was also quite aerodynamic and the weight distribution was strongly front biased.
     
  20. ElSupreme

    ElSupreme Model S 03182

    Joined:
    Jan 13, 2012
    Messages:
    4,279
    Location:
    Atlanta, GA
    Yes. The car picks up crosswinds very easily. Atlanta is very windy when there is wind. But yes it is more than a comparable car. It was much worse than my GTI. Not really instability (using the engineering definition). But the car gets pushed rather easily, and requires some active driving habits.

    Exactly Cd is pretty much only measured head on.

    I believe this to be the main case. Having a lower drag coefficient generally means you are disrupting less air, and also don't have a large 'wake' behind your car. If your air profile is less disrupted that means that a cross wind doesn't have to 'punch through' a layer of turbulent (or otherwise disrupted) air that would dampen it before it hits the car. Having a 'Kamm' rear end tries to tow around a high pressure (read stagnant) 'bubble' of air behind your car. During a cross wind that 'bubble' will be displaced somewhat. Creating a low pressure area. This will pull the car towards the area where the wind is pushing thus mitigating the effect on the car.

    There are of course so many things that can help/hurt cross wind yaw movement. Suspension settings, tire pressures, speed, steering feedback, wheels (yes wheels), pavements, center of gravity, pretty much everything dynamic on the car itself.

    I do not thing the car is unstable at all during cross winds. Just that it picks them up very easily. I haven't ever really had a problem with crosswinds in the Model S. But it dose require some active driving habits to stay planted in your lane.

    Also having a flat and close to the ground floor pan is actually good for downforce (assuming you aren't funneling tons of air down there), much better than standard car.
     

Share This Page