RE: Mercedes tyre 'skipping' - official statement
Discussion
Dave Hedgehog said:
Cyb3rDud3 said:
No they are not, they are 21" and only on MO marked tyre.
mine are a 20 and like wise have one MO tyre, but if you change the size slightly dozens of tyres are available its a conti and has zero tyre wall strength, they will be replaced with far superior tyres
Edited by Dave Hedgehog on Friday 27th January 17:07
rockin said:
That sounds like some of Donald Trump's "alternative facts" to me....
My RHD Porsche does it. My LHD Corvette does it. Am I surprised? No. They are both high performance cars with wide tyres and excellent handling at autobahn speeds.
I was referring, specifically, to the MB issue, rather than general. I'd assumed that was implicit, but obviously not. Sorry.My RHD Porsche does it. My LHD Corvette does it. Am I surprised? No. They are both high performance cars with wide tyres and excellent handling at autobahn speeds.
Hungrymc said:
The video looked pretty bad. Many of my cars have shown this trait to some extent and I've always assumed it's some compromise of Ackerman vs other factors (and 4 wheel drive performance cars generally been more pronounced than others). But none as bad as this.
If my car did what yours is doing in the video I'd be irritated, but a question. You are taking a full lock and accelerating on a most of those shots, I generally only crawl on a full lock (and am winding lock off as I accelerate). Are you doing it to highlight the problem? Or is that just a trait of some of the manoeuvres you have to make?
I agree, a tiny bit of slip can happen. Have had that when damp and cold with my Audi A4 Quattro as well. But nothing like this.If my car did what yours is doing in the video I'd be irritated, but a question. You are taking a full lock and accelerating on a most of those shots, I generally only crawl on a full lock (and am winding lock off as I accelerate). Are you doing it to highlight the problem? Or is that just a trait of some of the manoeuvres you have to make?
Same driveway and road I've lived at for the last 16 years. No car has ever done this. I'm honestly not going fast at all. It also does it when you go around mini roundabout, or basically any cross road turn.
kapiteinlangzaam said:
My Mustang does this in the cold, when the tyres are cold. 19" summer tyres. Full RH or LH lock, and worse on low-grip surfaces.
Disappears even in the winter once the tyres are warmed up.
It feels 'wrong', but its totally normal.
I know two people with Corvette C6s, and its the same on those.
Absolutely nothing to worry about.
It never disappears and still does it with warm tyres, and also in double digit ambient temperatures. I'm glad to hear you enjoy driving a car like that then, and having your tyres shred to pieces literally. I've never experienced anything like it ever.Disappears even in the winter once the tyres are warmed up.
It feels 'wrong', but its totally normal.
I know two people with Corvette C6s, and its the same on those.
Absolutely nothing to worry about.
My mk1 Punto used to do this. That was FWD (naturally)
I put it down to the geometry causing lots of positive camber to the outer wheel and equal amounts of negative to the inner wheel at full lock.
That was on something like 155/70/13 and the tyres were correctly inflated.
As per earlier posts, it manifested itself a lot during parking manoeuvres on smooth surfaces.
I put it down to the geometry causing lots of positive camber to the outer wheel and equal amounts of negative to the inner wheel at full lock.
That was on something like 155/70/13 and the tyres were correctly inflated.
As per earlier posts, it manifested itself a lot during parking manoeuvres on smooth surfaces.
Gadzooks, makes me pleased my two 'smokers' for winter, and if the white stuff falls, are a P38 Range Rover (on 'Mondial' alloys and with M+S tyres) and my 248k Audi A4 B5 Quattro Sport, flitted with Bridgestone Blizzaks.
Neither exhibits any hint of the issues that the Mercedes seems to suffer from, nor did they on summer tyres (summer being relative..). Obviously both have differing systems that drive all four wheels, so are we saying that transmission and chassis / suspension development have both taken retrograde steps in the intervening years...?
Neither exhibits any hint of the issues that the Mercedes seems to suffer from, nor did they on summer tyres (summer being relative..). Obviously both have differing systems that drive all four wheels, so are we saying that transmission and chassis / suspension development have both taken retrograde steps in the intervening years...?
Cyb3rDud3 said:
I agree, a tiny bit of slip can happen. Have had that when damp and cold with my Audi A4 Quattro as well. But nothing like this.
Same driveway and road I've lived at for the last 16 years. No car has ever done this. I'm honestly not going fast at all. It also does it when you go around mini roundabout, or basically any cross road turn.
That would drive me mad. Order of magnitude more than I'm used to.Same driveway and road I've lived at for the last 16 years. No car has ever done this. I'm honestly not going fast at all. It also does it when you go around mini roundabout, or basically any cross road turn.
dvs_dave said:
All these people with anecdotal experience with their 2wd car, please take the time to watch one of the vids posted on the specific issue before posting a gormless comment that it's normal. It is most certainly not normal what is being experienced in this instance. 
I think the trait of a skipping wheel on full lock is pretty common. But totally agree that what is shown in the Videos is a different level to anything I've experianced.Hungrymc said:
I think the trait of a skipping wheel on full lock is pretty common. But totally agree that what is shown in the Videos is a different level to anything I've experianced.
Ackerman steering geometry is fairly complex in modern high performance cars. From Wikipedia -"Modern cars do not use pure Ackermann steering, partly because it ignores important dynamic and compliant effects, but the principle is sound for low-speed manoeuvres. Some racing cars use reverse Ackermann geometry to compensate for the large difference in slip angle between the inner and outer front tyres while cornering at high speed. The use of such geometry helps reduce tyre temperatures during high-speed cornering but compromises performance in low-speed manoeuvres."
Properly done, the steering should optimise performance and minimise the low speed effects. Merc have achieved this with the LHD versions, but the RHD implementation appears to have increased the slow speed side effects. Or so it would appear.
dvs_dave said:
All permanent awd (particularly performance orientated) cars will have a tendency at full lock to grumble a little due to slight transmission windup.
All permanent AWD systems without a centre diff or viscous coupling will suffer from windup, but surely the Merc has a center diff? I wouldn't have thought they be using plate LSDs either, which can also cause tyre skipping.dvs_dave said:
It's part of the compromise between the optimal Ackerman geo and the awd system.
Ackerman is a separate issue. Windup is causes by the front and rear axles traversing different distances during cornering. Imperfect Ackerman causes increased slip angles on the inner wheel.Edited by Mr2Mike on Saturday 28th January 08:42
Edited by Mr2Mike on Saturday 28th January 08:43
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