Front nearside wheel shuddering when slowly turning (W222)

[gr1nch]

Hello folks,

I'm hoping this problem rings a bell with some members here..

First the car is 9 months old and under warranty and I'll be taking it in to the main dealer where I bought it, asap.

Driving normally there are zero problems, however it seems to happen only under the following conditions, when I reverse out of my drive, which is short and steep.

1. after I've just started the car
2. steering wheel turned more than a half clockwise (heading right)
3. on a slope
4. reversing
5. slow speed, maybe 2-3 mph.

With these conditions the front nearside wheel is bearing less weight than the other three wheels.

The result is a mechanical, semi-smooth shuddering, perhaps 2 or 3 small judders very close together, all within a second is say, otherwise normal. It does not always happen started happening about a month ago, but I put it down to the slightly slippery to mildly icy surface on my drive then. However it has been doing it in the dry too. I'm concerned.

Is this a known problem? Or you have an idea about what might be the cause?

Sent from my G3112 using Tapatalk

 

[DaleGM]

Hello folks,

I'm hoping this problem rings a bell with some members here..

First the car is 9 months old and under warranty and I'll be taking it in to the main dealer where I bought it, asap.

Driving normally there are zero problems, however it seems to happen only under the following conditions, when I reverse out of my drive, which is short and steep.

1. after I've just started the car
2. steering wheel turned more than a half clockwise (heading right)
3. on a slope
4. reversing
5. slow speed, maybe 2-3 mph.

With these conditions the front nearside wheel is bearing less weight than the other three wheels.

The result is a mechanical, semi-smooth shuddering, perhaps 2 or 3 small judders very close together, all within a second is say, otherwise normal. It does not always happen started happening about a month ago, but I put it down to the slightly slippery to mildly icy surface on my drive then. However it has been doing it in the dry too. I'm concerned.

Is this a known problem? Or you have an idea about what might be the cause?

Sent from my G3112 using Tapatalk

 

[DaleGM]

Don't concern yourself, the effect is caused at the tyre surface interface by the scrub radius of the front suspension geometry brought about by the relationship between the steering axis and the ackerman angle 'at that particular moment' of your manoeuvre along with the light wheel loading

 

[CJD]

As above - it's the Ackerman effect, no need to worry - often asked question on Porsche forums too.

 

[Bobby Dazzler]

The tyres harden in cold weather which is what makes the Ackerman effect more noticeable in winter. No need to worry, but if you were thinking about buying Winter tyres and the shudder bothers you, then reducing the likelihood of shudder in Winter can be added to the list of reasons to justify the purchase.

 

[gr1nch]

Thanks gents!

Don't concern yourself, the effect is caused at the tyre surface interface by the scrub radius of the front suspension geometry brought about by the relationship between the steering axis and the ackerman angle 'at that particular moment' of your manoeuvre along with the light wheel loading

Gobbledygook! Key technological concepts in there that I've never heard of, pre-Googling. Makes sense now though [emoji16]

As above - it's the Ackerman effect, no need to worry - often asked question on Porsche forums too.

Googling retrieved a lot of said posts. Very informative.

The tyres harden in cold weather which is what makes the Ackerman effect more noticeable in winter. No need to worry, but if you were thinking about buying Winter tyres and the shudder bothers you, then reducing the likelihood of shudder in Winter can be added to the list of reasons to justify the purchase.

Good to know.I've been thinking about getting winter tyres and this will speed up the decision.



Sent from my G3112 using Tapatalk

 

[DaleGM]

Thanks gents!

Gobbledygook! Key technological concepts in there that I've never heard of, pre-Googling. Makes sense now though [emoji16]

Googling retrieved a lot of said posts. Very informative.

Good to know.I've been thinking about getting winter tyres and this will speed up the decision.



Sent from my G3112 using Tapatalk

Key technological concepts I had to understand as I have built a race car and raced for 15 years so suspension dynamics and geometry was one very key component to learn about and understand if one was going to be successful, which I was. Google? I wish,, it was all books then. Happy New Year

 

[DaleGM]

Just in case you have an interest in such things as racing saloon cars. And by the way, that's yours truly on the left (1990's Brands Hatch)

 

[DRIVER200]

Hello folks,

I'm hoping this problem rings a bell with some members here..

First the car is 9 months old and under warranty and I'll be taking it in to the main dealer where I bought it, asap.

Driving normally there are zero problems, however it seems to happen only under the following conditions, when I reverse out of my drive, which is short and steep.

1. after I've just started the car
2. steering wheel turned more than a half clockwise (heading right)
3. on a slope
4. reversing
5. slow speed, maybe 2-3 mph.

With these conditions the front nearside wheel is bearing less weight than the other three wheels.

The result is a mechanical, semi-smooth shuddering, perhaps 2 or 3 small judders very close together, all within a second is say, otherwise normal. It does not always happen started happening about a month ago, but I put it down to the slightly slippery to mildly icy surface on my drive then. However it has been doing it in the dry too. I'm concerned.

Is this a known problem? Or you have an idea about what might be the cause?

Sent from my G3112 using Tapatalk

Try looking at the number of Posts on this in the AMG LOUNGE (examples below) and you might come to the conclusion that it's actually a design flaw on RHD cars. Don't be convinced that the Ackerman theory is actually a reason to put up with this far reaching problem.
RHD W213 E63 crabbing issue?
W213 E63s 4Matic clunking... Anyone else?

 

[DaleGM]

Why RHD models? They wouldn’t create differing SG’s for RH or LHD models, that would be nonsensical. I would agree that it should not be something that is necessarily acceptable but some some suspension configurations can be a compromise to get the best out of it for 99.9% of the time ~ when driving it.

 

[whitenemesis]

It's not so much the geometry as the tyres. As tyres get wider and lower in profile the issue manifests itself. It happens in many marques, not just MB

 

[DRIVER200]

Why then are MB offering winter tyres/wheels FOC to GLC owners experiencing this problem and not other owners?

 

[whitenemesis]

Why indeed ...

Good customer relations?

 

[DRIVER200]

Why indeed ...

Good customer relations?

So MB have decided that they want to keep GLC owners sweet and the other 4Matic owners driving other models have to pay for the masking themselves... that really is GCR!!

 

[DaleGM]

Why then are MB offering winter tyres/wheels FOC to GLC owners experiencing this problem and not other owners?

I haven’t checked but I’m assuming they would be narrower. As Whitenemisis correctly points out the wider the tyre the more it can be exacerbated. The wider the tyre the lower the profile (generally) and the walls just don’t have the compliance to deal perfectly (zero scrub) at the tyre/surface interface at that particular time. Winter tyres may well mask it vis-a-vis their construction.

 

[DRIVER200]

I haven’t checked but I’m assuming they would be narrower. As Whitenemisis correctly points out the wider the tyre the more it can be exacerbated. The wider the tyre the lower the profile (generally) and the walls just don’t have the compliance to deal perfectly (zero scrub) at the tyre/surface interface at that particular time. Winter tyres may well mask it vis-a-vis their construction.

This debate isn't really about whether winter tyres perform differently to non-winter tyres this problem is that you shouldn't have to fit different tyres for different weather conditions under normal circumstances. It's well documented that MB 4Matic cars suffer crabbing due to the different design of their 4Matic system which was originally for their LHD market but MB decided to apply to RHD drives cars and ended up with this problem. If you lived in a cold climate but drove a LHD car you would not have crabbing issues. You would only consider changing your tyres to winters in extreme conditions nothing to do with crabbing.

 

[Deleted member 113659]

Don't concern yourself, the effect is caused at the tyre surface interface by the scrub radius of the front suspension geometry brought about by the relationship between the steering axis and the ackerman angle 'at that particular moment' of your manoeuvre along with the light wheel loading

Are you Jonny Ball?

 

[DaleGM]

This debate isn't really about whether winter tyres perform differently to non-winter tyres this problem is that you shouldn't have to fit different tyres for different weather conditions under normal circumstances. It's well documented that MB 4Matic cars suffer crabbing due to the different design of their 4Matic system which was originally for their LHD market but MB decided to apply to RHD drives cars and ended up with this problem. If you lived in a cold climate but drove a LHD car you would not have crabbing issues. You would only consider changing your tyres to winters in extreme conditions nothing to do with crabbing.

In all fairness this now seems to have gone off piste a tad. The original question was simply about what was causing a front tyre to scrub when reversing on lock out of a steep drive. I think the basis of that issue has been addressed. My only thoughts on Winter tyres is that they may mask the issue as the geometry will remain the same ~ unless you feel the desire to drive it hard into wall

 

[DaleGM]

Hi Happy, you’ll need to enlighten me, who’s Jonny Ball?

 

[Bobby Dazzler]

Johnny Ball - Wikipedia