wide wheel/tyre steering 'slide' query

[grasmere]

Hi guys, I'd like to pick your brains please: I have AMG replica alloys all round fitted with 225/45/17 tyres. Front are Toyo proxes, ready to replace after approx 15k, and 2 almost new Contisport Contacts on the rear.

Problem is at the front: I have always sensed that the front wheels are being 'pushed' by the rear when turning. eg when on loose gravel entering or leaving a driveway and turning the wheels the front tyres seem to slide forward on the gravel even when moving slowly.

Now after just 15k of steady driving the fronts are ready to renew but I cant help feel that there should have been many more miles from them. Also the front left has worn a couple of mms more than the front right. Tyre pressures have always been ok and the same and the wear is very even across the tyre I wonder if the increased wear comes from the tyre sliding sideways slightly when turing on all roads - slightly but enough to increase wear rapidly ?

I am even considering replacing the alloys with original wheel/tyre sizes

Does anyone else experience the same feeling of front tyre slide with wide wheels or have any comment please?

 

[LazyBob]

At the risk of being shot at by the 'phaat' tyre brigade, wide tyres don't cut it on anything less than tarmac. The wider the footprint the less the tyres can 'cut' through the loose stuff on top, to gain traction on the hard stuff below. This applies to grit, gravel, snow and, to a lesser extent, water (as wide tyres tend to have wider water channels to compensate).

This can readily be seen in WRC cars (real ones, not road going versions) where they run wide, low profile, tyres for tarmac rallies and thinner, higher profile for gravel and to enable 120mph in snow and ice they run supper skinny tyres that cut through the snow to let the stud reach the ice below.

Despite sounding like an anti-wide tyre type, I do have 235s all round, but sadly only 16inches and a rubber tree like 60 section.

Blindfold on, last cigarette smoked, take aim ........

 

[pluggers]

Problem is at the front: I have always sensed that the front wheels are being 'pushed' by the rear when turning. eg when on loose gravel entering or leaving a driveway and turning the wheels the front tyres seem to slide forward on the gravel even when moving slowly.

Does anyone else experience the same feeling of front tyre slide with wide wheels or have any comment please?

I get this same thing as well but only when turning out of my drive,or on the rare occasion when I gun it in a car park.I just put up with it as its ok at all other times. And my tyres aren't that much wider than standard 215 compared to 195 I think.

 

[GrahamC230K]

Your low speed turning and the front wheel feeling like it is sliding, is EXACTLY what I was trying to describe (although never put it that way - doh! ) in this thread

http://mbclub.co.uk/forums/showthread.php?t=12206

The fault is has occured recently, ie I had my 17's before the fault and I hope to have it seen to this week by a specialist. Will let you know the putcome - most likely a worn bush of some sort.

 

[glojo]

At the risk of being shot at by the 'phaat' tyre brigade, wide tyres don't cut it on anything less than tarmac. The wider the footprint the less the tyres can 'cut' through the loose stuff on top, to gain traction on the hard stuff below. This applies to grit, gravel, snow and, to a lesser extent, water (as wide tyres tend to have wider water channels to compensate).

Totally agree with what you are saying,
Try driving on wet grass or snow with nice wide high performance tyres

Like you Bob I feel we might get shot down, but we can only talk from experience.

I appreciate in really heavy snow there might be an arguement for letting air out of tyres, but that is getting into specialist driving and not the normal road driving experience.

John

 

[Satch]

Gravel & some loose surfaces can end up much like having ball bearings under your front wheels. Less fricton because they are sliding over the surface so less steering effect. There is reason why driving a gravel stage in a Rally car is about as tough as it gets!

 

[GrahamC230K]

Do you get this steering both ways?

My interpretation of your fault only happens to me with right hand lock (forwards or backwards).

 

[Anders]

I get this too, and have only noticed the sliding feeling when turning right, e.g. out of a car park. I also believe that you can actually hear that the front wheels are scrubbing if you have the window down.

As mine is designed with the wide wheels, I think it could either be a general "feature", or a problem with a worn bush, or similar?

 

[andy_k]

it's all about steering geometry (or at least as far as I am aware) and the reason it only happens at the extreme full lock is because that is where the effects of turning are at their most exxagerated , as you turn on full lock on a surface such as gravel one tyre will have more grip than the other - usually the "outside" tyre as it's camber (or is it castor) angle will be less effected by the tight steering and it will remain in better contact as a result the inner tyre will get dragged sideways as only the edge of the tread will be in proper contact with the road.

To illustrate this for yourself turn the wheels to full lock and see how they are affected the nearer the end of their travel.

HTH

Andy

 

[nickmann]

it's all about steering geometry (or at least as far as I am aware) and the reason it only happens at the extreme full lock is because that is where the effects of turning are at their most exxagerated , as you turn on full lock on a surface such as gravel one tyre will have more grip than the other - usually the "outside" tyre as it's camber (or is it castor) angle will be less effected by the tight steering and it will remain in better contact as a result the inner tyre will get dragged sideways as only the edge of the tread will be in proper contact with the road.

To illustrate this for yourself turn the wheels to full lock and see how they are affected the nearer the end of their travel.

HTH

Andy

"Ackerman Angle"? Volvos and Triumphs (remember them?) used to have similar issues.

 

[didgit]

i have the exact same problem on my standard 202 16s left tyre worn on outside edge, presumed from turning into top of drive, the car does it turning both ways

 

[grasmere]

Do you get this steering both ways?

Interestingly it seems to be more pronounced when the wheels are turned right for me too - how odd but it does affect both ways yes.

 

[LazyBob]

i have the exact same problem on my standard 202 16s left tyre worn on outside edge, presumed from turning into top of drive, the car does it turning both ways

The front left outside wears on my W140 - seems to make some sense as it's the one that's loaded up on roundabouts. Also road camber means most cars 'drift' to the left so constant corrections (albeit tiny) to the steering will mean that the outer edge of the left front is the one that's loaded again.

Of course, my theory could be utter hokum and it is actually a factory suspension angle for whatever reason whatever it is tyre fitters seem generally aware of this 'feature' of W140s but as the rears disappear quite quickly it's easy to even it out by moving the fronts to the back where the load is usually on the inside edge of both rears (another camber angle I'm guessing)

 

[pluggers]

I recall vaguely when I had my first mot done on the car I was told the steering idler arm bush's were worn,Im wondering if this could be the problem as I never had them replaced, as it has never been picked up on any further mot's that have been done?