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

Torque Steer?

Discussion in 'Model S: Driving Dynamics' started by Stig, Jan 9, 2013.

  1. Stig

    Stig Member

    Joined:
    Dec 7, 2012
    Messages:
    15
    Location:
    Sunny California
    I'm going to throw this out there, knowing that I haven't done certain checks yet that I figured I would do, but has anybody else noticed a significant amount of torque steer after 4.x update?

    In particular - I've noticed that when I'm at speed (say 40mph+), when I accelerate past 40 kW (whether gradually or hard) - there is a significant pull to the right, enough for me to have to compensate. At first, I thought it was gusts of wind pushing me but then came to realize that I could replicate the result pretty consistently.

    Also as a side note that I have not decided whether I can consistently replicate is the pull back to the left when I let go of the accelerator abruptly.

    I'm due to rotate my tires soon - so I'll probably check to see how the wear is; I was also going to check the tire pressures, but considering I had just taken it to service a few days ago and the same thing has happened before and after the service (they are required to check tire pressure when i bring it in) - I suspect that the tire pressure is not an issue.

    Any thoughts?
     
  2. widodh

    widodh Model S R231 EU

    Joined:
    Jan 23, 2011
    Messages:
    4,822
    Location:
    Middelburg, The Netherlands
    Front-wheel drive cars are much more prone to torque steer. A rear-wheel drive car would have torque steer if the shafts at the rear aren't equal in length, but with Model S they are equal.

    I don't think it's torque steering, but what? I don't know :)
     
  3. TEG

    TEG TMC Moderator

    Joined:
    Aug 20, 2006
    Messages:
    17,249
    Location:
    Silicon Valley
    One of the front brake pads dragging? Uneven tire pressure? I would have it looked at... It doesn't sound right.
     
  4. ddenboer

    ddenboer MODEL X #1770

    Joined:
    Dec 21, 2011
    Messages:
    317
    Location:
    San Martin, CA
    I have noticed this recently as well, but need to check my tire pressure again (especially considering the TPMS failure - contact Tesla warning came on a few times today)
     
  5. smorgasbord

    smorgasbord Active Member

    Joined:
    Jun 3, 2011
    Messages:
    2,379
    Location:
    SF Bay Area
    I had something similar with my Roadster. An alignment fixed it.
     
  6. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,848
    Location:
    Ottawa, Canada
    Check your rear tire pressures. When I got my (used) S2000 it had a largish difference between the rear tires, and it would pull to one side under acceleration. First thing I checked when I got it home.
     
  7. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,743
    Location:
    Texas
    There is a small possibility that one tire has a poor conicity value. This can cause the car to pull to one side. Switching the tires from left to right would cause it to pull to the other side. This is probably not what you're experiencing, but I thought I'd mention it anyway.
     
  8. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    #8 PureAmps, Jan 9, 2013
    Last edited: Jan 9, 2013
    I've noticed something similar when I accelerate aggressively while steering, for example when merging onto the freeway or quick lane changes. I don't really notice a pull to one particular direction, but I do feel like the car is over/under steering resulting in me having to compensate. This results in a bit of a wobbly movement of the car. I've had no such issues in straight line acceleration. In all cases, I'm talking about very fast acceleration, not just your every day driving around.

    I had been driving with the steering mode set to "Standard", and I noticed that when I set it to "Sport" this effect was reduced. I'm thinking that maybe there is just too much play in the steering wheel in Standard mode that you can't quite control the car smoothly under such hard acceleration, and that allows the front wheels to wobble a bit resulting in under/over steer.

    I only have just over 350 miles on the car, so it could just be the tires need to settle in a little. I will inquire at my service appointment next week. I did see this mentioned in the Adam Carolla video review just before the 1 minute mark (with an incorrect technical explanation), so I know I'm not the only one:

    Adam Carolla Test Driving The Tesla Model S - YouTube
     
  9. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,848
    Location:
    Ottawa, Canada
    You really shouldn't be goosing the throttle while turning - you can easily exceed the grip of the tires. The stability control is probably kicking in to prevent you from spinning out.

    I always recommend people take an advanced driving school (i.e. on a race track) to learn how to safely handle a powerful car like this. It's amazing how much you learn.
     
  10. GSP

    GSP Member

    Joined:
    Dec 28, 2007
    Messages:
    1,993
    ^^^^^ Excellent advise.

    Driving school will improve the performance of your car more than any hardware mod, and it improves *every* car you ever drive!

    GSP
     
  11. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    Doug, I was exaggerating a little on the "mash the pedal" part. :) I just wanted to make it clear that this was not under what I would consider normal acceleration, but rather aggressive acceleration, so as not cause concern that this is a normal behavior of the vehicle. I've only ever truly mashed the pedal a couple of times on a straight away. BTW, when I've observed this behavior, I looked for any indicator lights to come on the dash and nothing lit up. I know the S has a light when traction control is engaged, don't know if it has one when stability control is engaged. So it seems like some looseness in the steering, tires, alignment to me.

    Your advice on taking a advanced driving course for anyone driving a high performance car is a good one never the less.
     
  12. strider

    strider Active Member

    Joined:
    Oct 20, 2010
    Messages:
    2,917
    Location:
    NE Oklahoma
    Yeah, I think this is the "Performance-tuned traction control" letting the car slide and then catching it. So I think you actually are breaking the rear end loose and the car is waiting to catch you which would feel like a "slide...catch. slide... catch" wobbling motion. I don't think anything is "loose" in the car.
     
  13. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    strider, you may well be correct. But shouldn't I see the TC indicator light up? Or maybe it's so brief that the indicator doesn't come on.

    Screen Shot 2013-01-12 at 12.50.00 PM.png

    I've been traveling and the bay area has been unusually wet the past few weeks, so I haven't had much time to experiment with the car's performance. I should finally get some "playtime" with the car this weekend and get a better feel for the car's dynamics.
     
  14. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    I went for a few fun drives over the weekend and found the cause of my "wobble". My rear tire pressures were out of balance, right rear was at 42 and left rear was at 47 (21" wheels). In fact 3 out of my 4 tires were at 47 psi. When I picked up the car, the DS told me he checked the tires and they were all at 42. I guess he was mistaken, and I never bothered to check after picking up the car.

    After letting the car sit overnight I readjusted all tires to 42 this morning, I went for a drive and it feels like I'm riding on rails. I'm not really detecting the pulling to one side or another that I was feeling before under hard acceleration.

    I'm not sure why the right rear was lower than the others, so I'm going to keep an eye on it for a few weeks. But otherwise, handling under acceleration has improved and the overall ride quality has softened a bit (not surprisingly).
     
  15. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,848
    Location:
    Ottawa, Canada
    Called it! :tongue:
     
  16. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    You called out a few different possibilities. You were bound to be right on one of them. :)

    But yes, you were correct. I drove Saturday and tried to determine if it was traction control or something kicking in. But even with lighter acceleration I could get a slight pull to one direction, so I decided to check the tires. Amazing that a 5 psi difference between the drive wheels can make such a difference...
     
  17. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,848
    Location:
    Ottawa, Canada
    Huh? I made two posts, one suggesting tire pressures as the source of your problem.

    The other had nothing to do with you. I was responding to PureAmps comment:
    .
     
  18. wycolo

    wycolo Active Member

    Joined:
    May 16, 2012
    Messages:
    2,421
    Location:
    WY
    > A rear-wheel drive car would have torque steer if the shafts at the rear aren't equal in length, but with Model S they are equal. [widodh]

    With IRS, wha??
    --
     
  19. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,743
    Location:
    Texas
    The only person you ever trust for tire pressures is yourself. You don't know how many times the gauge at the shop has been dropped. Sometimes you don't even know what kind of gauge they used. Also if they checked the tires when they were warm, the readings would be inaccurate (one tire could have been sitting in the shade and the other three in the sun). Get a good pressure guage such as model 50406 or 50404 and check your tires in the morning before you drive more than one mile (slowly).
     
  20. PureAmps

    PureAmps Model S P85 (#2817)

    Joined:
    Oct 22, 2012
    Messages:
    354
    Location:
    SF Bay Area
    A quick followup on this.

    I just picked up my car from the Fremont service center and they determined there was a slow leak in my right rear tire. I think the tires were all probably equal pressure (but too high) when I picked up the car in late December. The slow leak resulted in some of the behavior I was experiencing. Since they were all set too high, I didn't get a tire pressure warning as it was leaking because it was still above 42 psi. After I adjusted everything to 42, everything was great for a few days, but the night before I was going to take it in for service, the tire pressure warning did come on (since it was now probably below 42), so I had them investigate.

    Hopefully problem solved for now, but I will still keep an eye on it. Tesla really needs to add a basic diagnostics screen to the console that shows tire pressures, battery/motor temps, etc.

    As has been stated many times: check your tire pressures after delivery!
     

Share This Page