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MEG Sergeant
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1,156 Posts
Discussion Starter · #1 ·
Hey all,

I've got an odd problem with the Mondeo - when I'm near full lock, ie, doing tight turns, I get a really odd sensation, as if one or more of the front tyres is being dragged, if that makes any sense.

Makes a noticeable jolt when it happens and it can happen 2-3 times during a manevour! I've also noticed excessive tyre wear on the outside edge of my nearside front tyre.

I've had a quick look at the suspension and everything seems fine - the car had brand new wishbones and droplinks fitted both sides last month and this didn't fix the problem although curiously the problem DID go away for a week when I had new tyres fitted, but then it returned.

Any ideas? I was thinking maybe the alignment could be out so the wheels are not inline when I'm turning?
 

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One time Mondeo owner - now an outlaw!
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6,199 Posts
I have the same problem, which I think is down to a bent steering arm - that was Wheelsinmotion's on-line diagnosis some time back anyway.

I have yet to get it checked out properly, but it is probably as a result of clipping the edge of a kerb in Devon a couple of years back (one of my most embarrasing moments ever - took out both tyres on the left hand side. :( )
 

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MEG Corporal
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2,647 Posts
I believe I have the same problem too. Do you find it does it more/more noticable when the roads are wet/damp? Mine is more noticable when turning right on/near full lock. (though I never move at any great speed or hold it at full lock anyway since I had the driveshafts change because of the CV joint fault)

The only thing I have changed is the o/s anti roll bar link last summer...oh and I have ST170 wheels fitted since sept 2004, though I think it has been fine on these wheels, certainly up until about last September (2005). My next move is to change back to my ST24 wheels to see if it makes a difference as the offset for the ST170 wheels is much greater.
 

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MEG Sergeant
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1,156 Posts
Discussion Starter · #4 ·
I don't know if it makes a difference if its wet or dry actually, I've not noticed.

I've got the ST24 wheels fitted to mine so if its the same problem then I don't think refitting them to yours will cure it.

Bent steering arm sounds alarming - I cannot remember ever hitting anything like a curb but come to think of it the road near my house is pretty much pothole central, might have hit one of those..

Surely though the garage changing the wishbones would have noticed something like a bent steering arm?

Is it worth getting 4 wheel laser alignment done or is this unlikely to make any difference at all - would rather not waste 40 quid :)

Thanks guys!
 

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MEG Corporal
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2,647 Posts
Well, I've never hit anything and nor has my brother before me and we've had the car since it was 8 months old, so bent steering is probably out of the equation. It was fine up until last year...strange. I think I'll change the other link bar and try the changing the wheels anyway.
 

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Geometry Guru
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688 Posts
Be wise with Laser alignment?....this is linear (straight lines) and of no value to you.

The angle in question on a full lock is termed as
Toe Out On Turns
AKA
Ackerman Theory

If the machine measures that then you are safe, if not just burn the money and same yourself some time.
 

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MEG Commander
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3,573 Posts
Mine does something similar when reversing out of my drive on lock. And it seems worse when wet.

Wheelsinmotion - doesn't even the old "john beam" type geometery kit only measure with the wheels straight? Can anywhere measure the Ackerman Theory stuff?
 

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MEG Sergeant
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1,156 Posts
Discussion Starter · #8 ·
wheelsinmotion said:
Be wise with Laser alignment?....this is linear (straight lines) and of no value to you.
I guess, but then if the front wheels are not quite pointing in the same direction when straight, this problem will still exist when I'm turning as the wheels should usually be parrellel to each other?
 

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MEG Commander
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3,573 Posts
But laser alignment doesn't consider the wheels when they are turned, only when they are straight.

The effect of a bent steering arm will only be clear when the steering is turned.
 

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One time Mondeo owner - now an outlaw!
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6,199 Posts
Fox2 said:
wheelsinmotion said:
Be wise with Laser alignment?....this is linear (straight lines) and of no value to you.
I guess, but then if the front wheels are not quite pointing in the same direction when straight, this problem will still exist when I'm turning as the wheels should usually be parrellel to each other?
I'm no expert, but I think the wheels are at a slight angle to each other (toe in or out) to improve feel - if they were perfectly parallel it would tram line like, er a tram!
 

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One time Mondeo owner - now an outlaw!
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6,199 Posts
HJS said:
I have the same problem, which I think is down to a bent steering arm - that was Wheelsinmotion's on-line diagnosis some time back anyway.

I have yet to get it checked out properly, but it is probably as a result of clipping the edge of a kerb in Devon a couple of years back (one of my most embarrasing moments ever - took out both tyres on the left hand side. :( )
Just to clarify the above, my car has been through two MOTs since the kerb strike. There is no visible bend in the steering arm, not to my untrained eye, anyway!

I don't know if it's related, but I also have a knock from the left hand side, which I'm assured isn't dangerous, but no-one can find the cause of it.

Returning to the alignment problem, my car seems to handle fine in normal driving (I'm not one for barreling into corners anyway, to be honest), its just when on full right lock you can hear the nearside front tyre scrubbing, which doesn't happen to the off side on full left lock. The outside edge of the near side tyre wears down, but not to the point where that tyre needs replacing ahead of the off side.

Also, when I back off my drive on full right lock, the near side wheel almost feels as though it is lightly loaded and being dragged sideways, if that makes sense.

And on the subject of steering, when I go from lock to lock at very low speed, or stand still (which I know you shouldn't do) the front of the car seems to rise. Does anyone else find this?
 

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Geometry Guru
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688 Posts
Mate can you have a read on my site www.wheels-inmotion.co.uk go to Steering Geometry/Axis Deviation Theory.... this will explain your initial complaint.... the go to Kingpin Inclination Angle Theory..... this will explain the lifting of the car lock on lock.... i am not being lazy but a full explanation here would just drone on.
 

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The never ending project is close to finishing
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829 Posts
I had the same problem, was two front broken springs :eyesup: Check it properly as it was my top coils that had gone :L
 

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Big Megger
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300 Posts
When moving slowly the tyres may indeed feel as though they are being dragged, this is because; As we all know when turning the inside wheel follows a smaller arc to the outside wheel. The outside wheel then is moving faster than the inner. The same happens across the width of the tyre, only there is no diff between both edges to adjust the speed. Therefore the tyres will skip or scrub Due to the forces being applied!
 

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Geometry Guru
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688 Posts
Your analogy is correct assuming the inner wheel has the correct Ackerman, by convention the inner wheel should own 1degree 30' taken from the outer wheel at 20 degrees..... in conversation this cannot be proved or denied so Geometry time it must be!
 

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Big Megger
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300 Posts
Regardless of the Ackerman, the inside edge of a tyre will try and turn through a corner at a different speed to the outer edge of that same tyre. This can cause the wheels to skip/scrub at low speed. In fact it happens at all speeds, but is only noticable at low speed.
 
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