Mercedes GLC Clonking and juddering on near full steering lock

[Tony Mac]

Statement posted on GLCForum indicating how MB UK are planning to resolve the crabbing and juddering fault for GLC owners - not the most positive message, but acceptance that they have a problem with the GLC


24 February 2017


For the attention of Market Area Directors, Sales Directors, After Sales Directors, General Managers, Sales Managers, After Sales Managers, CSU Managers


Dear Colleague

Further to our interim update last week, we are now able to provide a more detailed technical explanation regarding this issue.

Due to the positioning of the front axle differential on right hand drive cars, the steering position differs very slightly compared to left hand drive models. When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation. This is more pronounced during cold weather and when larger wheels and low profile tyres are fitted.

We can assure you that our technical specialists, as well as independent experts such as DEKRA, concur that the cars remain completely safe to drive.

Fitment of All Season tyres counteracts the sensation. We are therefore securing sufficient stocks of these to provide to customers who find this uncomfortable.

· Mercedes-Benz Cars UK will contact GLC customers who have already registered a Compass complaint:
• Customers with 17”, 18”, 19” and 20” tyres will be offered a set of All Season tyres (once available) and fitment free of charge
• For GLC 43 AMG customers who have cars with 21” tyres, a 21” All Season tyre is not currently available. We will offer these customers the option of taking 20” wheels and All Season tyres, or waiting for 21” All Season tyre availability

· We would ask you to please do the same for GLC customer complaints that you have received and managed locally or for any future GLC complaints about this issue until further notice

· Please also take the following action for customers who have ordered their car but have yet to take delivery, and for future customers of existing dealer and pipeline stock until further notice:
• Please make sure they are aware of this characteristic.
• Customers proceeding with delivery have the option to take All Season tyres as soon as they are available or to wait and change to them if/when they experience this sensation in Winter 2017/18.
• For customers who do not wish to take delivery of their GLC with summer tyres, please offer a courtesy car until the All Season tyres are available for their car.

For all the cases above concerning provision and fitment of All Season tyres, please submit a goodwill claim against damage code 2113800.
We will provide updates concerning any interaction we have with your customers, together with availability of the aftermarket All Season tyres and the logistics process involved.

Yours faithfully




David George Sally Jones
Sales Director Customer Services Director
Mercedes-Benz Cars Mercedes-Benz Cars


Emma Passmoor

Customer Services MBuk

 

[rf065]

I wonder whether those saying it is normal will put their claim in now as well.
Still loads of questions to be answered around the details, but at least Mercedes has admitted there is an issue and that it isn't normal.

If you read the statement from Mercedes, "When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation."

Nowhere in their statement does it say it's not normal, What they have described is the Ackerman principle, nothing else. The offer of new tyres is to mask the effect, nothing else has changed, this is not a magic fix that's been announced because only a complete redesign of the front steering/suspension will change that.

In the context of the way the car has been designed, it's still normal and Mercedes cannot change that now.

Russ

 

[dejongj]

If you read the statement from Mercedes, "When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation."

Nowhere in their statement does it say it's not normal, What they have described is the Ackerman principle, nothing else. The offer of new tyres is to mask the effect, nothing else has changed, this is not a magic fix that's been announced because only a complete redesign of the front steering/suspension will change that.

In the context of the way the car has been designed, it's still normal and Mercedes cannot change that now.

Russ

So you totally ignore the part preceding that statement?

I'm not saying at all that this is a magic fix, I'm not saying that Mercedes can fix it. I'm saying that it isn't normal for vehicles to do that, and it is clear that there is a difference to LHD vehicles.

I give you that using your very specific wording that in the context of this vehicle it is normal. Yes, using that language you may have a point.

But come on be a man, eat some humble pie. It is clear this is not normal. Mercedes even acknowledges that, they have done previously by highlighting it is merely a comfort issue, they have now gone one step further and highlight one of the differences (they still haven't touched upon the planetary gear set differences as well), they are even putting their hands in their pocket to change the setup of the vehicles by supplying different tyres (and wheels if I read the intent of the 21" option correctly). But yes please keep perpetuating that it is all normal they all do that

 

[rf065]

But yes please keep perpetuating that it is all normal they all do that

But they do, it's how they have been designed and that will not change. You cannot beat the laws of physics as they say.

Russ

 

[dejongj]

But they do, it's how they have been designed and that will not change. You cannot beat the laws of physics as they say.

Russ

I just had to keep this for history; of course they do Russ of course they do. I wish I could say I agree, I wish I could say I was happy to follow the advice of so many on here that it is normal and they all do that. But luckily some of us demand higher quality standard, have very different quality experiences and realise that this is not right, that it is not correct, and that they don't all have to do this.

Funnily enough, even Mercedes seems to agree with us now and working towards finding a permanent solution. Or do you think they just change tyres for fun on 10,000 cars. Or do you think they just instruct dealerships for fun to put people in courtesy cars until the parts required are available?

Keep digging buddy, keep digging

 

[DRIVER200]

Dumb question but can ALL WEATHER TYRES be used all year round or just during winter months?

 

[190]

Yes they are a cross between summer and winter tyre.They are generally worse than both i.e. in the summer they don't grip as well as a summer tyre and in the winter they don't grip as well as a winter tyre. Things are improving though and there are rave reviews about a new Michelin cross climate all weather tyre.

 

[dejongj]

Dumb question but can ALL WEATHER TYRES be used all year round or just during winter months?

It all depends on which or what tyres they are going for now I'd think. In my experience they are a compromise for every season. However I happily admit that my experience is old and I stood corrected when people introduced me to like what Michelin has been doing with their Cross Climate tyre.

I find this an interesting comparison.
Michelin Cross Climate vs Winter and All-season tyres | Evo

Yet then there was also this;
All-season tyres test 2016/2017: top all-weather tyres tested | Auto Express

Looks like there are some significant compromises as well.

 

[grober]

So "Les Vacances de Monsieur Ackerman" as Jacque Tati might have said.
The way to compare this would be to measure TOOT at various steering angles including full lock in RHD and LHD GLC vehicles. I can only assume that on full lock that Ackerman goes way out compared to LHD vehicles.
http://www.mbclub.co.uk/forums/amg-...mg-owners-what-shall-i-do-19.html#post2421353
PICCIES
the GLC COUPE suspension and front drivetrain- you will have to imagine the engine sump position between the differential housing and the "washer" on that transverse drive shaft.

Unfortunately the steering rack position is not shown in that diagram but the similar LHD 2wd coupe rack is shown here. Notice where the input from the steering column enters the rack [ partially obscured by the anti roll bar] and mentally shift it across to the other side for RHD You can then see how the 4 MATIC differential position might intefere with the steering column input to the RHD rack.

 

[DRIVER200]

It all depends on which or what tyres they are going for now I'd think. In my experience they are a compromise for every season. However I happily admit that my experience is old and I stood corrected when people introduced me to like what Michelin has been doing with their Cross Climate tyre.

I find this an interesting comparison.
Michelin Cross Climate vs Winter and All-season tyres | Evo

Yet then there was also this;
All-season tyres test 2016/2017: top all-weather tyres tested | Auto Express

Looks like there are some significant compromises as well.

 

[Tony Mac]

But they do, it's how they have been designed and that will not change. You cannot beat the laws of physics as they say.

Russ

Rubbish - The clever engineers at MB managed to design around Ackerman on the left hand drive GLC's to make a non-crabbing and juddering free car for the Europeans and North American markets

Tony

 

[st13phil]

Further to our interim update last week, we are now able to provide a more detailed technical explanation regarding this issue.

Due to the positioning of the front axle differential on right hand drive cars, the steering position differs very slightly compared to left hand drive models. When the steering is on full lock this steering angle difference can result in the front tyre skipping sensation.

So, taken at face value - and I see no reason why not to do so - it's a packaging issue that has caused different steering geometry to be adopted on RHD cars using this platform, and nothing to do with transmission wind up.

Sorry to have to say this, but I suspect that current owners won't see any form of engineering solution to this and that swapping out the tyres is as good as it's going to get.

My guess is that one of three things will happen for the future regarding this 4WD platform:

1. It will remain as it is, and cars will be delivered with "special" tyres fitted as standard
2. The RHD variant of the 4WD platform will be quietly dropped and the cars will be available in 2WD form only in RHD markets
3. The drivetrain packaging / steering system will be re-engineered for RHD cars for the facelift in 2 or 3 years time

 

[dejongj]

So, taken at face value - and I see no reason why not to do so - it's a packaging issue that has caused different steering geometry to be adopted on RHD cars using this platform, and nothing to do with transmission wind up.

Sorry to have to say this, but I suspect that current owners won't see any form of engineering solution to this and that swapping out the tyres is as good as it's going to get.

My guess is that one of three things will happen for the future regarding this 4WD platform:

1. It will remain as it is, and cars will be delivered with "special" tyres fitted as standard
2. The RHD variant of the 4WD platform will be quietly dropped and the cars will be available in 2WD form only in RHD markets
3. The drivetrain packaging / steering system will be re-engineered for RHD cars for the facelift in 2 or 3 years time

Don't be sorry - I think you may be correct. I'm sure there will be a few more variants/options but I doubt there will/can provide a proper fix in place.

 

[trapperjohn]

Its been a long haul for all those involved, perhaps now there is some light at the end of a very long tunnel.

As my friend Charles Morgan would say, lets hope its not an express train coming right for you.

CHEERS

 

[DRIVER200]

Don't be sorry - I think you may be correct. I'm sure there will be a few more variants/options but I doubt there will/can provide a proper fix in place.

Not wishing to throw petrol on the fire but when you think of all the other major car manufacturers who still have this problem for several generations of their cars you sort of wonder if it will ever completely go away. But hey that's for another day.

 

[DRIVER200]

Its been a long haul for all those involved, perhaps now there is some light at the end of a very long tunnel.

As my friend Charles Morgan would say, lets hope its not an express train coming right for you.

CHEERS

In my experience ''Light at the end of a very long tunnel'' is normally your boss with a torch bringing you more grief/work!!

 

[dejongj]

Not wishing to throw petrol on the fire but when you think of all the other major car manufacturers who still have this problem for several generations of their cars you sort of wonder if it will ever completely go away. But hey that's for another day.

RHD market may be too small to design it properly out of the car. However as many of us have experienced it really doesn't have to be there or noticeable at all. My GLS from Mercedes didn't do it. My courtesy car the GLE doesn't do it either. Just to name two Mercedes cars.

I would hazard a guess that avoiding it to this extend requires doing the design for the LHD model whilst keeping the RHD model in mind. Or perhaps the larger vehicles (which is mainly where my SUV experience has been) have just simply more space to deal with these issue and the smaller SUV's just are too small to compensate for the differences between LHD/RHD. I really don't know, I'm purely speculating.

 

[st13phil]

Or perhaps the larger vehicles (which is mainly where my SUV experience has been) have just simply more space to deal with these issue and the smaller SUV's just are too small to compensate for the differences between LHD/RHD. I really don't know, I'm purely speculating.

That's my guess. LHD to RHD is never as simple as mirroring the setup, not least because engines have a nasty habit of having components on one side of them that aren't on the other. A physically bigger car gives the engineers more space to play with, so more scope to place components where they ideally should be rather than where they have to go because that's the only place they'll fit. Add in requirements for crash performance and things can get very challenging.

 

[John Jones Jr]

Rubbish - The clever engineers at MB managed to design around Ackerman on the left hand drive GLC's to make a non-crabbing and juddering free car for the Europeans and North American markets

Tony

You are correct, it is total rubbish. But there will always somebody with their own agenda for whatever reason that will defend the manufacturers, especially car manufacturers (blind brand loyalty maybe) instead of calling it as it is.

The logical conclusion is that there is clearance issues between the steering column/steering rack due to the location of the front diff on R/H/D cars and the compromise to fit the diff leads to the crabbing issue.

There has always been problems with fitting 4WD (turbos too) to R/H/D thus no availability, it's nothing new, this has been a problem for decades with vehicles that were initially designed in L/H/D format. Just this time M-B overcame most of the hurdles bar getting one or two calculations wrong it would seem.

 

[hallra]

My only worry would be how much this actually goes towards solving rather than masking the problem, its a bit like use winter tyres solution Mercedes attempt to put a sticky plaster over it?

There are already complaints on Mercedes Crabbing from a Lady on 18" wheels with all season tyres, she confirms the solution ain't gonna work as she already on all season tyres.