Strange juddering when on full lock - QV - Alfa Romeo Forum
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Strange juddering when on full lock - QV

Hey guys,

Had my Giulia QV for a few days, absolutely love it! One thing that is slightly annoying is the juddering the car does when on full lock. I.e. when I'm trying to reverse into a parking space or going round a tight roundabout. Anybody else have this? It's like a juddering, or like the wheel is scraping on something? It's a bit off-putting!
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yes, every one does that its the suspension setup combined with super summer tyres.
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Have the tracking checked.
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Commented on many times here. It's down to the agressive suspension geometry and is totally normal. They all do it.
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+1. This has been discussed numerous times on this forum. Do a search. Affects all Giulias not just Qf irrespective of wheel size. You get used to it. Official bulletin copied below:

SUBJECT:
Chattering Noise While Steering

OVERVIEW:
This bulletin involves discussing a chattering that might be heard from the Alfa Romeo
Giulia front suspension.
MODELS:
2017 (GA) Alfa Romeo Giulia

DISCUSSION:
The Alfa Romeo Giulia is characterized by unique suspension characteristics featuring
patented AlfaTM Link technologies, developed in order to deliver the best dynamic
performance in any driving condition.
In particular, the front double-wishbone with semi-virtual steering axle scheme allows an
“Ackermann” angle change with the variation of the steering angle. Ackerman angle is
described by the different steering angle between the left/right front wheels.
This feature, which is normally reserved for premium sport cars, has been the object of
specific tuning by Alfa Romeo engineers to ensure the lowest vehicle understeer in any
driving condition and to achieve a breakthrough in Giulia driving dynamic best in class
steering feeling, enhanced safety and driving pleasure.
At the maximum steering wheel angle, the specific tuning above mentioned makes the
front suspension deliver a lower steering angle from the right to left front wheels,
generating a perceivable dragging phenomenon on the inner wheel, which can be
perceived as a “chattering” accompanied by some noise which is influenced by one or
more the following conditions:

· Driving surfaces and air temperature.
· Tires pressures.
· Tire specification, size and brand.
· Steering angle and speed of the vehicle.

NUMBER: 02-003-17
GROUP: Front Suspension

DATE: March 10, 2017
Such behavior may be noticed in the different conditions is only correlated to the above
mentioned parameters, and is no indication there is an issue with the vehicle.
This behavior is inherent to very specific Alfa Romeo engineering development, which is
the maximization of the vehicle safety, and does not affect in any way the vehicles safety,
tires, or indicate a mechanical part failure.
POLICY:

Information Only.

=========================================
Giulia 2.0 T4 MA (2017), Triumph Speed Triple 'R' (2016).

Previous:
159 2.2 JTS - 2008 - Goodbye Feb 2017.
Ducati 899 Panigale - 2014 - 2016.
Kawasaki Ninja ZX 6R - 2004 - 2014.
=========================================
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Ackermann (not HD) google is your friend here.

same happens on lots of cars of this ilk.

will go away mostly when your summer tyres are warm or if you replace them with ones for colder weather.

Skippy hes called round here.
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Also filed under "scrubbing". All Giulias do it AFAIK. It does though seem to be dependent on tyres. The tyres I had fitted from new did this to such an extent that I was almost afraid to turn at full lock, with almost unfortunate consequences. The winter tyres I have on at present hardly do this at all. I'll be cursing again when I switch them over in a few weeks.
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Quote:
Originally Posted by Skilaree View Post
Have the tracking checked.
No need to do this - common with all Giulias... don't worry, you'll get used to it (eventually)!
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Thanks Guys - apologies I should have searched. But good to understand why this is happening.
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My Porsche used to do this so I've never been bothered by it on the Giulia.
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You're in good company because my GTA also does that!
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Really think that the dealers should start to explain this at the hand-over. Must be one of these queries every other week now

Anyway, enjoy your Giulia - [email protected] sure you will...
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Quote:
Originally Posted by TOX1C View Post
You're in good company because my GTA also does that!
My GTA never did in 13 years on standard tyres and wheels.

Andy
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Really think that the dealers should start to explain this at the hand-over. Must be one of these queries every other week now [IMG class=inlineimg]https://www.alfaowner.com/Forum/images/smilies/biglaugh.gif[/IMG]
Anyway, enjoy your Giulia - [email protected] sure you will...
Chris Variava do. It was explained to me before the test drive.
Absolutely nothing to worry about.
If it bothered you that much, change the tyres and the problem goes away.
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Posted this in another thread, but it really belongs here. I thought it would be nice to explain exactly what is happening with the steering.

By way of background, when a car takes a corner, the inside wheels are required to complete a smaller circle the outside wheels (think of a car going round a round about).

Most road cars have what is known as an Ackermann steering set up. In simple terms, it means that when the steering wheel is straight the front tyres are pointing slightly away from each other. The benefit of this is that, when you take a corner, the inside wheel is turned more than the outside wheel. Another way to think of it is that the angle the tyres are pointed generally matches the direction they are required to go.

The Giulia on the other hand has a reverse or an anti Ackermann steering set up. This means that the tyres means that when the steering wheel is straight the front tyres are pointing slightly towards each other. Consequently, when you take a corner, the inside wheel is turned less than the outside wheel. Counterintuitively this has benefits during high speed cornering. In particular, it keeps the tyres cooler whilst providing better grip. This is why many race cars are set up with anti Ackermann steering. The downside is that at low speeds, the inside tyre is pointed in the wrong direction causing it to, in effect, be dragged over the road. This dragging is what caused the noise.

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FYI you don't get this problem when you change off the Corsas...I have had Corsas, Michelin Pilot Alpin 4's and Michelin Pilot Sport 4S's on the car and the only ones which skipped/Juddered where the Corsas..
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The Pirelli’s on my Stelvio do this whether it hot or cold and they’re higher profile!
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We really ought to have a sticky topic that new owners could read, detailing little foibles like this.
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Some people feel that it’s better for it to turn up randomly in other threads where it can’t be found.
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Quote:
Originally Posted by Insert_Name View Post
Posted this in another thread, but it really belongs here. I thought it would be nice to explain exactly what is happening with the steering.

By way of background, when a car takes a corner, the inside wheels are required to complete a smaller circle the outside wheels (think of a car going round a round about).

Most road cars have what is known as an Ackermann steering set up. In simple terms, it means that when the steering wheel is straight the front tyres are pointing slightly away from each other. The benefit of this is that, when you take a corner, the inside wheel is turned more than the outside wheel. Another way to think of it is that the angle the tyres are pointed generally matches the direction they are required to go.

The Giulia on the other hand has a reverse or an anti Ackermann steering set up. This means that the tyres means that when the steering wheel is straight the front tyres are pointing slightly towards each other. Consequently, when you take a corner, the inside wheel is turned less than the outside wheel. Counterintuitively this has benefits during high speed cornering. In particular, it keeps the tyres cooler whilst providing better grip. This is why many race cars are set up with anti Ackermann steering. The downside is that at low speeds, the inside tyre is pointed in the wrong direction causing it to, in effect, be dragged over the road. This dragging is what caused the noise.

My expectation is, rather than the Giulia having Reverse Ackerman geometry, that it has somewhat less than exact Ackerman, ie it is somewhere between 'Ackermann' and 'Parallel' on the figure. I believe that Reverse Ackermann on a road car would lead to wholly unacceptable levels of front tyre wear.

Andy
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Whatever it achieves it does look a bit more expensive than McPherson struts. I think the aim is to achieve perfectly vertical articulation so that the contact patch will be greater than other systems thus exaggerating the greater distance traveled by the outside tyre on the corner?
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Quote:
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Most road cars have what is known as an Ackermann steering set up. In simple terms, it means that when the steering wheel is straight the front tyres are pointing slightly away from each other.
Whereas what you write is mostly true, this part is not.
Toe-In which is both wheels pointing inwards (what the Giulia should have from factory) only adds to the anti Ackermann effect and will lead to a very fast (and maybe nerveous) reaction when steering into a corner.
The Giulia will still have anti Ackermann when set up with Toe-Out. Toe-Out will actually reduce tyre wear on the outer flank, add some virtual camber and will lead to a slightly slower turnin but at a better level of control.

Still this all wont change the anti Ackermann which is really a different radius when turning into a corner (and show right in the diagram).

Regarding setup I can recommend this page in German, however one can read a lot from the pictures
https://www.racecarsuspension.ch/set...ps-und-tricks/


P.S. double wishbone is better than McPherson but it has nothing to do with the Ackermann

Last edited by compert; 21-05-19 at 17:41.
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