Cmonyoureds
Active Member
Yes that’s what I thought too, I was putting the question to Alfaitalia who said that hard tyres should reduce tyre skipping.
GLA AMG 35 - Front Tyre "Crabbing" and excessive wear
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ALFAitalia
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I really depends on the surface... My wife's A Class does it quite badly on painted multi storey car park floors.....but it slowly fades as the tyres get worn and harder....YMMV!
RobertT
New Member
Thanks for all the views and comments. After some deliberation I may bite the bullet and go for michelin crossclimate 2 tyres all round instead. The reason being there will still be a risk of the same problem with any summer tyre. So although Mercedes recommend winter tyres to alleviate the issue which is a non starter for our UK weather, I thought an all season tyre would be the best compromise. Albeit I'll need to come down a speed rating or two which I'm given to understand is ok if this information is displayed to the driver. Will keep you informed if this happens and if the problem is lessened or hopefully cured, although I won't be holding my breath.
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Why are winter tyres a non-starter in the UK?
Steve84N
MB Enthusiast
Probably because they are a bit pants for two thirds of the year so you need two sets of wheels/tyres.
grober
MB Master
First off there are some primary differences between the GLC and GLA drivetrains. GLC is primarily a rearwheel drive chassis with frontwheel drive assist. The GLA is primarily a frontwheel drive system with rearwheel drive assist. The GLC crabbing problem arises from an steering Ackerman problem as already alluded to on right hand drive cars only , due to a packaging problem involving the frontwheel drive system and the steering geometry--- this was addressed with new front suspension uprights [save for the AMG models I believe?]
Because the engine in the GLA is transverse ,packaging difference between left-hand drive and right-hand drive cars does not exist as far as drivetrain and steering interference is concerned. One possibility that has occurred to me is if the rearwheel drive "assist"is cutting in too aggressively in cold slippery conditions. This would have the effect of pushing the car forwards from the rear wheels while the front wheels are trying to turn the car at the same time. Again this effect could well be mitigated by tyres that retain greater grip at lower temperatures- i.e. winter or all-weather tyres which contain a different rubber content containing more silicone which helps to maintain grip at lower temperatures in addition to their tread patterns. Are there any 4wd drivetrain adjustments you can make via driver control settings or are they fixed?
Because the engine in the GLA is transverse ,packaging difference between left-hand drive and right-hand drive cars does not exist as far as drivetrain and steering interference is concerned. One possibility that has occurred to me is if the rearwheel drive "assist"is cutting in too aggressively in cold slippery conditions. This would have the effect of pushing the car forwards from the rear wheels while the front wheels are trying to turn the car at the same time. Again this effect could well be mitigated by tyres that retain greater grip at lower temperatures- i.e. winter or all-weather tyres which contain a different rubber content containing more silicone which helps to maintain grip at lower temperatures in addition to their tread patterns. Are there any 4wd drivetrain adjustments you can make via driver control settings or are they fixed?
grober
MB Master
RobertT
New Member
I meant in the context of only having to purchase one set of tyres rather than two and the all season seems the best compromise
RobertT
New Member
Unfortunately there aren't any adjustments I can make. Just for info, I wrote to both the boss of Mercedes Cars and the boss of Mercedes AMG and they provided this explanation -
''The distribution of weight on the front axle differential is different for all cars and manufacturers from left to right hand drive. In line with the Ackerman Principle this means there is a dependency on the tyre wall flexibility to help absorb the angles of steering when on a firm lock. This is especially prevalent when the rubber on the tyre is cold as the reduced elasticity and flexibility of the tyre side wall results in a lack of absorbsion and essentially the tyre skips whilst trying to grip. It is something which can be felt only at very low speeds, and when a certain percentage of wheel lock is engaged for turning.
As per the Mercedes-Benz Digital Handbook for any car, we would always recommend the use of correct and approved tyres including winter tyres for temperatures which fall below approximately +7 degrees.
This isn’t a safety issue.''
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That’s a fair explanation and consistent with comments in this thread.
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I completely understand. Ultimately there’s (almost) always a compromise somewhere, and as you suggest the compromise for winter/summer tyres is that they need to be switched over. The compromise on all season tyres is that they’re never optimal for conditions, and in your case whilst they’ll stay more flexible than summer tyres in cold conditions, they won’t be as flexible as winter tyres.
All season tyres will help with the skip but if it really is driving you crackers then I would go for Winter tyres in case all season tyres don’t fully eliminate the issue, or it returns quickly as the tyre ages/wears. To switch tyres it takes me an hour, twice per year for each car, which for me is a reasonable trade off, but that may be too much of a compromise for others.
RobertT
New Member
Probably if I was a high miler I might consider it. But as I'm only doing 6-7000 miles a year hopefully the tyre wear issue with all season won't be a problem for a few winters.
grober
MB Master
By way of analogy----A 35 amg----doubt they changed the drive train -- suspension /ground clearance obviously?-I do recall intial press release saying the front rear drive balance software was biased towards the rear more in the AMG models to give a sportier feel
RobertT
New Member
UPDATE - Hi all, just thought to let you know that Mercedes Amg have thrown another spanner in the works - apparently "All Season" tyres are a no no. I've copied some of their message below:
"Our Manufacturer's Recommended winter tyre options are 'V' rated (149mph), therefore, moving to a 'W' rated tyre which has a higher speed profile would not present any logistical issues with the vehicle. However, as we do not have a recommended 'W' rated winter tyre option, I cannot make any recommended on manufacturer or brand.
Our tyre recommendation for your vehicle is the following:
Pirelli P Zero MO1 (235/50 R19 99V HM+S).
In your email you also suggested the use of All-Season tyres: This is not something supported by Mercedes-AMG as the braking distance of the vehicle may be affected, compromising the safety of the vehicle. Use of winter tyres will reduce the 'tyre skipping' characteristic as winter tyres have a better tyre sidewall flexibility in temperatures around 7°C or less."
Talk about making life difficult!!
"Our Manufacturer's Recommended winter tyre options are 'V' rated (149mph), therefore, moving to a 'W' rated tyre which has a higher speed profile would not present any logistical issues with the vehicle. However, as we do not have a recommended 'W' rated winter tyre option, I cannot make any recommended on manufacturer or brand.
Our tyre recommendation for your vehicle is the following:
Pirelli P Zero MO1 (235/50 R19 99V HM+S).
In your email you also suggested the use of All-Season tyres: This is not something supported by Mercedes-AMG as the braking distance of the vehicle may be affected, compromising the safety of the vehicle. Use of winter tyres will reduce the 'tyre skipping' characteristic as winter tyres have a better tyre sidewall flexibility in temperatures around 7°C or less."
Talk about making life difficult!!
they belong in the bin
Steve84N
MB Enthusiast
What utter nonsense. Winter tyres will often increase the braking distance when the conditions aren't bad enough. Unless it's full on icy the all season will probably brake in a shorter distance than the winter. All season tyres may be slightly less pliable than winters but they also remain flexibility under 7 degrees.
They don't know what they're on about. It's not the sidewall flexibility, it's the tread blocks. Winter tyres have deeper grooves and sipes in the blocks so they squirm around. All season tyres tend to have some sipes but less than winters.
Ignore them and fit CrossClimate.
Watch this.
RobertT
New Member
Yes I tend to agree. Lets face it , tyre stopping distances vary greatly between different makes of tyre anyway due to compound,tread design etc so if safety was really an issue in the first place wouldn't Mercedes cars all come with the same type and make of tyre that has come top in tests?? A Michelin Cross Climate surely is safer than the Yokohamas I have currently.
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Mercedes are assuming that you’ll use each tyre in the correct operating temperature window, ie switching to winter tyres when the ambient temperature is regularly below 7 deg C, and switching to summer tyres when the ambient temperature is regularly above 7 deg C.
When used in the correct operating window, a winter tyre will out perform an all season tyre, and a summer tyre will out perform an all season tyre. The all season tyre is designed to deal with opposite extremes which means that it’s always compromised, and never performing at its best.
Steve84N
MB Enthusiast
@Bobby Dazzler that's the traditional view of all season tyres. If you watch the video above you'll see that the CrossClimate outperforms the winter in the sort of conditions we see the most in the UK.
The guy who runs that channel uses all seasons instead of winters because our climate isn't severe enough to justify winters. Granted he swaps onto summer tyres because they outperform in the warmer months but CrossClimate still works well then where a winter does not, saving the need to switch tyres.
The guy who runs that channel uses all seasons instead of winters because our climate isn't severe enough to justify winters. Granted he swaps onto summer tyres because they outperform in the warmer months but CrossClimate still works well then where a winter does not, saving the need to switch tyres.
RobertT
New Member
There are dozens of tyre manufacturers and when Autobild or whoever does for instance a "Summer" tyre test, so all the tyres are suitable for the same ambient temperature, the stopping distance and handling can vary hugely between the various tyres. So my point was if tyre safety was really a main concern for Mercedes or indeed any car manufacturer why don't they just fit tyres that come out best in the tests as standard or even tell owners not to fit certain makes of tyres(that a bit big brotherish!). I presume they'll just say that each tyre still performs within the safety parameters which is why I was a bit taken aback by their opinion of the all season tyre.
