tiger_x

After recommendations from any Perth folk on here. I have a stone chip that needs repair. Its probably going to need a little filling as its deep.Who in Perth can i trust my car with ?

Citizen613

decorily

Someone needs to get a life!!

redrover22

With the same tyres I had a very similar wear pattern and got 34000 kms without rotation.

Front left wears the most with some feathering on the outside. While it is normal for left side to wear a little quicker I think this feathering is due to the crabbing issue as it put a lot of force on this tyre around roundabouts on hard lock.

I have new tyres now and was thinking of a wheel alignment but may skip it given they are tracking very well and the wear I had seems very common and not necessarily a wheel alignment issue.

Citizen613

You could be right !!! LOL.

Teckno

bips

Is there any evidence that these changes have had any effect, either on tyre wear, or crabbing?

Teckno

redrover22

For me the extra wear on the front left tyre isn't significant enough to justify a wheel alignment.

Also, I would question the alignment to stop crabbing being the best for the car in terms of performance. The other cars suffering this crabbing issue are Porsche and Alfa Romeo who are obviously tuning their handling for fast corners rather than car parks and roundabouts.

Let's see how I go on these new non RFT tyres as the crabbing is greatly reduced, which I think will mean less feathering on the outside front edge of the tyres.

Citizen613

What tyres did you go with Red ??

redrover22

Hankook 2554520 105Y K120

Much much better turn in and traction and comfort. Noise improved but that may just be because they are new.

bips

I don't know what to make of that. Is there really a trade-off between crabbing and handing? Is so why don't all good-handling performance cars crab? Because if you're paying that sort of money for a premium car you don't want to put up with that sort of phenomenon. What surprises me is that Porsche and Audi owners are.

This interests me too. I've wondered whether the tyre change really solves the tyre wear problem, or just masks it.

redrover22

Hi Bips,

The reason this Ackerman effect is becoming a new phenomenon is because of the size of the tyres vs turning circle that we have on new cars these days. It seems to becoming more and more prevalent and is exasperated by large low profile wide tyes, run flats and geometry on Mercedes RHD cars.

This is somewhat explained simply here http://www.mcgrathautoblog.com/autom...ette-stingray/

cheers


The compromises are

bips

That's an interesting link. Thanks. But it doesn't explain to me why crabbing, or the Ackerman effect, is prevalent in RHD GLCs but only very, very rarely in LHD. That link suggests that you can choose to mitigate the effect or not by design. But surely the design of both RHD & LHD is much the same only reversed?

redrover22

As far as I know the problem with RHD and Ackerman effect is due to the location of the transfer case when switching the steering over.

The point I am making is that the Ackerman effect created by this compromise in steering geometry, due to the transfer case location, may not necessarily be a bad thing depending on how you look at it.

I understand this car may be considered more of a luxury car, but if I fit new non RFT performance tyres and the effect is greatly reduced and I have much better handling then surely this is a win?

If I get the tyres realigned now, which have then been adjusted to mitigate the Ackerman effect, then I may be heading in the wrong direction in my case. As long as they are wearing well and tracking well then I don't see the need for a change.

Teckno, a new car that arrives with poor wheel alignment is a poorly prepared car. These settings should be checked before delivery. I have suffered this once with an Alfa 147 that had very high front tyre wear. It was realigned when a tyre was damaged beyond repair and replaced by a supplier of cheap tyres in Sydney (where bips bought his wheels) and the result was more than terrible. Had it redone by a tyre place in Sydney who was ironically the place that did the wheel alignments for Sandersons Mercedes and the owner was a Alfa owner/enthusiast and they did a magnificent job.

Nowadays I would only realign them by a Mercedes dealer (if needed) or go back to that place in Woolloomooloo if they are still there.

Teckno

Teckno

Teckno

down under

Hi team...GLC 43 built JAn 2017...my original ContiSports were showing major wear at 6000 (six thousand !!!!!) and told i would need new tires ....so.....told them that the crabbing issues were unacceptable, and the tires were not fit for purpose....so MB replaced front 255 40 21 with new Contisport 5's , gratis, and, and CRABBING completely disappeared!!!!

Sport mode is better than comfort...less float

Will be getting aftermarket wheels and 19 inch tires for what i consider unacceptable tire noise on the Hume Hgway, and patter on poor suburban roads.

tiger_x

Were they the Conti star series they put on? Im waiting to hear back from MB what they are going to do for mine.

Citizen613

All very interesting, the ongoing discussion regarding tyre wear.
After reading many forum threads on the subject, I come to these conclusions - (Caveat - I have no technical experience on these matters ..just my views)

- It appears that MB have made some compromises in the front end geometry of the GLC
- These compromises are not unique to MB ...other manufacturers have similar issue with some models.
- RHD vehicles appear to have suffered worse, because of the position of the transfer case and the steering components.
- The point Techno is making is that over time the published wheel alignment specs from MB have changed.
- There is definitely some variance in vehicles coming out of the factory ..similar vehicle with same tyres exhibit different behaviours.
- Some OEM tyres appear to be sub standard in performance compared to retail versions of the "same" tyre.
- Runflat or MOE specification tyres appear to exacerbate the issue.
- While reluctant in the beginning, the MB dealerships are trying to mitigate the issue, with tyre replacements, but no so much wheel alignment adjustments. This intrigues me!

All of the above makes it difficult for us as individual customers to have a meaningful conversation with the dealerships about the issue.
Equally, it must make it difficult for the MB service departments to sort thru the issues.

I have never been soooooo tyre focused with any other car I have owned.

Teckno

down under

yes, they are the star series...i suspect the MOE product was a substandard fitment...(dont sell or release to the general public)

have ordered 19 inch wheels from RIMS USA, 8.5 front and 9.5 rear, to replace the 21 inch rims, and will likely put MICHELLIN Latitude 3's as Runflats to see if ride quality is better or more 'luxurient'...

down under

yes, they are the star series...i suspect the MOE product was a substandard fitment...(dont sell or release to the general public)

have ordered 19 inch wheels from RIMS USA, 8.5 front and 9.5 rear, to replace the 21 inch rims, and will likely put MICHELLIN Latitude 3's as Runflats to see if ride quality is better or more 'luxurient'...

Teckno