Car Shuddering at High Speed Turns

Strange thing today, driving along the M5 about 3 hours out of Sydney, everything fine except a long traffic jam. We stopped at a rest area for lunch, then took off to continue, quickly reaching 110 again.

Had to take a reasonably "sharp" turn in the road, is I had to turn the wheel more than just the usual nudge, and the car started shuddering. At the end of the curve it straightened up and the shuddering stopped. A bit further on a similar sharper curve, shuddering again.

Can't remember if there were any similar right hand curves.

At lower speeds, eg 80 it didn't seem to happen, or maybe those curves weren't as severe.

I pulled into the next rest area and tried to reproduce it with very sharp turns, doing circles in the car park in both directions, but there was no shuddering, although it was also at a much slower speed.

Called the NRMA who couldn't see a reason for it. We ended up driving back to Sydney without incident, no shuddering, although again I don't think I encountered the same severity of curves.

Was thinking of getting the wheels checked for balance/alignment? And a mechanic to check for other things?

Any ideas what could cause that?

Comments

  • +6

    I'm surprised NRMA sent out a roadside tech for this issue on Good Friday or any day for that matter.

    What year / make / model of car?

    Taking a sharp turn at 110kmh in a Getz will be different to an F90 M5 CS.

    How old / many kms are the tyres and when were they last balanced? When was your last wheel alignment?

    • Sorry, good point, 2013 Forester, tyres are a year old and that was when they were balanced and when the last week alignment was.

      • Have you checked the tyre pressures recently?

        • +1

          A few weeks ago and they were good, and the NRMA guy said the tyres look ok.

          • +1

            @kiitos: Hit any curbs recently?

            If it only happens on high speed sharp curves the condition may have existed for ages. It sounds like you don't typically drive these road types - just metro driving.

            My guess is a wheel bearing but it could be any number of things. It's pretty easy to test. Google is your friend.

            • @MS Paint: Yes, initially I thought something happened somehow after the first rest stop but later realised it could have been there a while since normal city driving speeds didn't cause it to happen.

              There have been a huge number of potholes that have sprung up in Sydney with the train and I have hit a few of them, including today on the way down.

              • +5

                @kiitos: This is the answer. Trains cause massive pot holes (so I've been told)

                Exhibit A

                • +1

                  @MS Paint: Argh, second typo I can't correct :-)

      • +1

        That should be "last wheel alignment".

    • Its fairly obvious to me…..

      Probably NOT wheel bearings.
      These are not symptoms for that
      You would normally hear a slight grinding or low hummimg noise

      The cheapest and only way out!!!!
      Get your WHEELS BALANCED!!!
      The tyre guys will also check the wheel rims and tyres for uneven wear or any lumps or knocks to the rims

      Damage could have easily resulted from hitting one of the 000s of pot holes around after all that rain !

      You can check wheel bearings yourself by jacking up the wheel and spinning it listening or feeling for any grinding noises by keeping hand on the tyre as you turn it. Also grab tyre on both sides and give it a shake back and forth to see there is any slack. You can also grab it at the top and push back and forth again to see if there is and slack movement. If its loose you can take off the hbb cap and tighten the bearing by turn the large nut but only nip it up. Not too tight.
      Simple stuff really

      Thats it folks
      HAPPY EASTER

    • Thanks, that's useful

  • +1

    Wheel alignment

    • -2

      Sorry WRONG answer
      OP did not complain about car pulling to right of left

      • +1

        wheel Alignment doesn’t always result in pulling to one side.

  • +7

    Impressed you spent 3 hours travelling on a 30 km long road

    • Ok, fair enough, Hume Highway.

    • +1

      I was imagining op doing mainies up and down the M5

  • +1

    Next time don't hit the ripple strips when turning …

    • That's what we initially thought, but we tried driving over them later to compare and it was definitely not that.

  • -6

    It might be the car.

    Try changing that first.

    • +1

      weird flex, but OK.

  • +2

    My guess would be wheel bearings.
    On AWD systems on tight corners I find shuddering can occur, although not on sweeping corners.

    Doesn't have diff locks does it?

    • I don't think it has a diff lock.

      If it is the wheel bearings, did the fact that it only happens on turns indicate that it's the front wheel bearings that are the issue?

      • +2

        The change in forces can cause it to happen
        Other option would be cv joint, check the cv boots are still intact and not leaking

        Cv joints aren't too bad to replace

      • +1

        I was thinking wheelbearings too. But it probably would only occur whilst turning at speed in one direction- either left or right - if it’s both wheel bearing’s could be shot on both sides but that would be unlikely both fail at exactly the same time unless you just didn’t notice before

        • I can't recall if it happened on tight right curves, or if we even encountered such curves. We noticed it on a couple of tight left curves.

          Does that mean that it's definitely one of the front wheel bearings, and neither of the rear wheel bearings?

    • Wheel bearings make a distict grinding noise, not shuddering

  • +1

    Dodgey CV, Wheel nuts, wheel bearings, shit roads plenty of options.

  • -2

    Have you checked your oil level?

    • Engine oil? Yes, and it is fine, although a few weeks ago I got an oil warning light and had to top it up, but can't see any leaks.

  • +3

    The best thing about driving a Subaru in Oz is that the Yanks have documented pretty much every problem you will ever encounter, like this:

    https://www.subaruforester.org/threads/2002-shaking-at-highe…

    Due to the AWD complexity, it could be suspension or drivetrain on your car and is impossible to tell without an inspection

    Since you're in Sydney, I would personally take it to a Subaru specialist like Subie Doctor or All Drive Subaroo

    • Thanks, I'll read through those threads, and check out the recommendations you gave.

  • I've been trying to find the places and mechanics open today in my area and ones I've used are closed over Easter.

    If the wheel bearings are the problem, is it risky driving around Sydney at non highest speeds until next week?

    Is there a risk of something catastrophic happening in this case?

    • +1

      Unlikely. Just get it checked as soon as you can. I also reckon it'll be the CV joint or a wheel bearing. Possibly it's suspension knock, but that usually shows up on slow speed tight turns.

  • Pop it up on a jack and spin the wheel. Give it a push, pull too/bottom and side/side to see if there’s any movement. Do all wheels. Don’t climb under the car while it’s on a Jack.

    • Ok, I've done this now. The rear wheels were solid top/bottom and side/side. The front wheels were solid top/bottom, and both had a very small amount of play side/side.

  • I remember having a rental that was fine up until it reached a certain speed then shook like a smoothie being made. It was wheel alignment. I’d start there.

  • +1

    If you are driving Mercedes GLC AMG they call it crabbing issues. Google that.

  • It's possible that it is the viscous coupling in the transmission. Does it also shudder at very low speed with steering at full lock when warm?
    If so then it's the coupling.
    If it's an automatic you may get away with a fluid change as it is a clutch plate system. Manuals are a sealed unit and require replacement. Exchange units are available.

    • It didn't shudder when i was driving in tight circles, I think at full lock, in the rest area car park, not sure of the speed, maybe 20ks or so?

      • Was the rest area car park a high grip highway like surface, or was it low grip dirt or loose gravel over bitumen? Windup only occurs on high grip surfaces because the tyres can't slip.

        • Wollogorang, New South Wales
          https://maps.app.goo.gl/EA1ABR3NQ2YSiRJ77

          It was pretty good bitumen, might have been some loose gravel but generally smooth and solid, I didn't feel I was doing something unsafe when i tried the circles.

          (And from the photo, it looks like others like doing circles here too!)

  • +1

    Just like you need a diff on each driven axle because the left and right wheels travel a different distance when you're turning, when both front and rear axles are driven the wheels on them travel a different distance on curves too. With 4WD engaged on a high grip surface like a highway at speed, unless you have a diff between the front and rear axles you can get an effect called windup, which manifests as a juddering.

    On a part time 4WD when you only engage 4WD when you have poor traction you don't need that centre diff, because the tyres can slip just enough to prevent windup.

    On a full-time 4WD where you are going to be in 4WD at high speed on a high grip surface you do need something in the drivetrain to prevent windup. I believe the OP's model Subaru has a clutch of some sort that does that job. When the front-rear axle speed difference would cause juddering it slips just enough to release the load. The symptom the OP is describing fits what would happen if that clutch is not slipping when its supposed to. Sorry, I don't know enough about Subarus to say why that might be.

    • If the centre diff has failed it should shudder at low speed on full lock. Happened to my Forester. At higher speeds you don’t turn as sharply so there less difference in wheel travel front to rear so it’s less likely to shudder at highways speeds. Of course, it also depends on the failure mode as to exactly how the symptoms will show.

  • My first thought is a bit simpler than some of the above suggestions.

    When they balance wheels they use small lead weights it's possible one of these weights has come off the rim and depending on the speed you can get shuddering.

    I would get a wheel balance and alignment I'm 90% certain that's the problem and if it's not they could give you a better idea of what the problem is.

    • +2

      That would be likely if the shuddering occurred when the car was being driven in a straight line, not just when it was going around tight corners.

    • That occurred to me too. Check the wheels to see that they all have balance weights in/on them. Look for something that has recently dislodged from inside the rim I think get just use double sided tape on alloy wheels unlike the old clip on ones that were used on steel.

      Out of balance wheels is more likely to show up at high speed.

      If the unbalanced wheel is slightly unloaded during cornering (as the car body rolls) it’s possible that the shuddering may occur more when cornering. Could also explain why it only occurred going left and not right.

      • +1

        In Australia left hand curves in the road are sharper than right hand turns, because for a given cornering radius for the road overall, and speed limit and recommended maximum cornering speed, a car on the left hand side of the road is on the inside of the turn and is turning a smaller radius curve. So any problem where cornering is a factor is more likely to be obvious on a left hand curve.

        • What? Only if the left hand curves are the same radius as the right hand. On any given drive the right hand bends might be the sharper of the average bend due to the course of the road.

          Anyway, my point was because the OP mentioned it happened on left hand bends but didn’t notice it on right hand bends.

          • @Euphemistic: No, on the highway we drive at the speed limit, or at the speed on the advisory speed sign. They are both the same in both directions. So on the same road, on the same curve, the vehicle to whom it is a left hand curve is cornering harder because we drive on the left hand side of the road so it is on the inside of the curve and turning tighter at the same speed. So if something is more likely to occur if you are cornering harder it is on the left hand corners you'll experience it.

            It is only on a race track where you drive as fast as you can, use all the road, and corner as hard as you can in both directions you'd expect to encounter it whether the curve is to the left or right.

            • @GordonD: On a trip where you travel the same road back and forth, yes. But otherwise any given trip wether left or right is largely determine by the course of the road. It could be that a particular road has lots of sharp rights and only sweeping lefts - and vice versa.

              Tyre bloke told me the passenger front wears most - because roundabouts, right turns.

  • maybe one of these

    wheel balance
    tire balance
    wheel alignment
    brake pads
    loose wheel nuts

  • Definitely sounds like CV joint, have had exact same experience and was fixed with CV joint being replaced

  • Subaru Forrester is a CVT transmission, CVT's are notorious for failing and one of the first signs of failure are shuddering on turns or when slowing down.

  • -1

    Last time I had shuddering it was the catalyst converter breaking down and contaminating the fuel supply, but then you'd have infrequent shuddering as you're driving around.

    • The catalytic converter is in the exhaust, not the fuel supply line.

  • +1

    i reckon its a lower control arm bushing, for a 2013 forester they tend to crap out at this age (mine did at 85,000km).

    cost about $400 to replace both front bushings from my stealership

    • Thanks, this could be a likely suspect, the car has done about 93k KMs.

  • I took it to a tyre place and they recommended replacing both front lower control arms @ $655 each side. They said they were worn and didn't mention bushings.

    Called Subaru and they want to do a diagnostic check before replacing anything, but will get back to me with a quote for the same, although the girl mentioned bushings automatically so not sure if replacing the whole control arm is unusual?

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