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Twitchy steering?


PWBarrett
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[update: Fixed! - see post from 7/1/2013]

 

I've never had a car with electric power steering before, so maybe they're all like this, but...

 

Does anybody else find the power steering to be a bit twitchy, especially at highway speeds?

It seems like there's a small distance you have to turn the wheel before much happens, then it jumps to the next increment, rather than being a smooth continuous process.  So at highway speeds, I keep over-correcting, a step too far to one side then a step too far to the other.  I'm probably making it sound worse than it really is, but it gets tiring after a while.

At residential street speeds I usually don't notice it.

Edited by PWBarrett
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I notice it too. Mainly with straight stretches with subtle pressure to correct drift. It feels like the tension gives way for an instant then tension again. Also have felt it with cross winds.

I wouldn't say it is unsafe, but a little unsettling.  I'm coming from an '07 supercrew F-150 that was perpetually slightly out of alignment, so not a complaint just an observation.

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Yep! Same thing here. I rented a C-max the week before mine arrived, it was a little twitchy on the hiway. Mine does the same thing. So it's something inherent in the car. Be curious if a factory alignment setting is off (doubt it) or its something to do with the EPAS system ( most likely). And like the other poster, not sure I want to bring this up with the dealer --yet.

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Yes, I've noticed twitchy steering too.

 

One other thing is that it seems that the car has a slightly hard sounding clunk whwn hitting minor potholes just the right way (sometime they are hard to avoid).

Anyone else notice that?

 

 

No to either either issue.

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I don't have "twitchy steering".  For those that do, what air pressure do you run in your tires?  I've had electric steering in another vehicle and not had this "twitchy steering".  I do run more pressure than the manufacturer recommends.   

 

Low air pressure will reduce sidewall stiffness. At high speeds this may lead to a feeling that when slightly turning the steering wheel, the car is not turning.  The car will continue to want to go straight due to this additional flexing of the sidewall for a fraction of a second and then begin to turn. If one would sense this and turn the steering wheel slightly more, one has over-corrected for the turn.   Higher air pressure will reduce flexing and give more responsive steering.  

 

So, see if increasing the tire pressure up to 44 psi has an effect. 

 

What I do notice though is that in windy conditions, I have to correct less with my C-MAX than my other vehicle that does not have EPAS.

Edited by Plus 3 Golfer
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The tires are all at 39 PSI.

What I'm getting isn't that the wheel turns and the car doesn't seem to turn, it's that there's a slight resistance to turning the wheel in the first place, like there's no assist until it's turned a degree or two, then the assist kicks in and it jumps just slightly.  It's usually not all that noticeable.

That having been said, the steering is more precise, i.e. less slop than any of our current or previous cars.

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Does it happen at all speeds?  When I turn the steering wheel ever so slightly, the wheels turn.  In essence, there is no slop / dead band that I can notice like conventional hydraulic steering might have where you can rock the steering wheel a degree or so back and forth with no effect on the wheels.

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I'll have to try it again next time I'm in the car, but as I recall it probably is at all speeds, it's just that at slow speed, that little bit of turning is insignificant, and most wheel turns are much larger.

I've had plenty of cars with sloppy steering, and this is definitely nothing like that.

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Maybe there's a software adjustment in the EPAS or maybe I'm not sensitive enough to the issue since my previous vehicle had electric assist steering.  I'll be taking the C-Max out this afternoon and will experiment with the steering and since we have a wind advisory today with gusts up to 55 mph, I will get a feel as to how good the EPAS really is in strong winds. :)

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I'll see if I can explain what we're experiencing a little better.  --PWBarrett, feel free to make any additions or corrections to the description

 

There is no "play" in the steering wheel at all.

 

driving down the freeway in a straight line --between 65 and 70-- holding the steering wheel in one spot.  As the road surface changes or the wind changes, the car will respond ever so slightly in one direction or the other based on what's changed.  The car will every so slightly follow a new course without moving the steering wheel at all.  Then, the moment you begin to compensate with the wheel --again there's not play in the wheel, you're responding with just pressure on the wheel to compensate-- the car responds and in some cases an ever so slight over compensation.  

 

I need to be very clear this is ever so subtle!  it is only noticeable on a straight road, traveling over some distance where you can just put the car on a straight line and leave it.  I never feel it running around town, or even short jaunts up to 50 or 60.  Its only really noticeable when you're cruising.  And the changes are ever so slight.

 

One other point. If you are a "one handed" driver on the freeway, its more noticeable as I'm constantly having to make minor adjustments to keep the car in the lane.  The pressure from the hand to make the adjustment is more than what I've experienced in other cars.  By the time you apply the ever so slightly needed pressure to get the car to compensate, it responds a ever so slightly to much.

 

Again, I think this is related to EPAS primarily, but also could be related to alignment --but unlikely.  Its kind of like driving an old rear engine Porsche.  They tended to follow the road, yet a tight steering wheel.

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Okay, I drove today between 65 -70 mph in very windy conditions (about 20 -25 mph sustained and with higher gusts) - cross, tail and frontal winds.  The car tracks extremely straight even in cross winds with slight pressure on the steering wheel in the direction the wind is coming from.  If there is a gust or lessening of the wind, I can feel a correction (like dalebunker describes) which could be called a "twitch" -- wind subsides (eg, going through an underpass), steering wheel still has pressure towards wind direction, EPAS and driver correct when car starts drifting into the lessened wind direction (driver puts pressure on steering wheel with the direction of the wind).  Seems to driver like over correction and driver moves steering wheel back to neutral position / slightly back into wind direction so car tracks straight.  This is very subtle and virtually not noticeable to me.  It amounts to just shifting the pressure on the steering wheel only slightly - probably less than a degree.  I wouldn't call it "turning" the steering wheel though.

 

But I would says that with EPAS, there is considerably less effort by the driver to keep the car tracking straight in windy conditions.

 

I would guess the same things could happen when traveling on roads with ruts.

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I'll see if I can explain what we're experiencing a little better.  --PWBarrett, feel free to make any additions or corrections to the description

 

There is no "play" in the steering wheel at all.

 

driving down the freeway in a straight line --between 65 and 70-- holding the steering wheel in one spot.  As the road surface changes or the wind changes, the car will respond ever so slightly in one direction or the other based on what's changed.  The car will every so slightly follow a new course without moving the steering wheel at all.  Then, the moment you begin to compensate with the wheel --again there's not play in the wheel, you're responding with just pressure on the wheel to compensate-- the car responds and in some cases an ever so slight over compensation.  

 

I need to be very clear this is ever so subtle!  it is only noticeable on a straight road, traveling over some distance where you can just put the car on a straight line and leave it.  I never feel it running around town, or even short jaunts up to 50 or 60.  Its only really noticeable when you're cruising.  And the changes are ever so slight.

 

One other point. If you are a "one handed" driver on the freeway, its more noticeable as I'm constantly having to make minor adjustments to keep the car in the lane.  The pressure from the hand to make the adjustment is more than what I've experienced in other cars.  By the time you apply the ever so slightly needed pressure to get the car to compensate, it responds a ever so slightly to much.

 

Again, I think this is related to EPAS primarily, but also could be related to alignment --but unlikely.  Its kind of like driving an old rear engine Porsche.  They tended to follow the road, yet a tight steering wheel.

 

That sounds like what I'm experiencing.  At highway speed, a slight pressure doesn't do much if anything.  A slight pressure more over-does it a bit.  I just have to make more small steering adjustments than I'm used to, rather than just a constant slight pressure being sufficient.  Maybe it is more prevalent in cross-winds or on slight curves.  I'll see if I can pin it down more.

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Yes, I've noticed twitchy steering too.

 

One other thing is that it seems that the car has a slightly hard sounding clunk whwn hitting minor potholes just the right way (sometime they are hard to avoid).

Anyone else notice that?

 

I certainly wouldn't describe my steering as twitchy. In fact I'm kind of bummed that it seems less sensitive and precise than in the C-Max I first road-tested.

 

I have definitely noticed the pothole clunk though --- a bit like the sound a car with worn-out front strut tower bushings makes. One owner who complained about a front-end clunk ended up having the dealer replace a lower control arm under warranty, but I'm not sure if it was the same clunk. :-)  Every FoMoCo product I've ever driven has had a too-soft front suspension -- like it needs a stiffer spring, stiffer compression response on the shock, more suspension travel, or a longer/stiffer bump stop -- and I suspect this is just the C-Max version of that phenomenon. Wouldn't be surprising, especially considering a C-Max is a lot heavier than the Focus from which it's derived.

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