Mercedes GLC "tyre hop"
Mercedes GLC "tyre hop"
This is a fair bit out there on this subject on the net already, but much of it low level and questionable.
In discussion with a colleague yesterday regarding his just-purchased 2019 Mercedes GLC. Something like 10 months old, less than 8000 miles. Former owner, the Mercedes dealer (ex-demo / staff car presumably). It's the 220d (probably irrelevant) but with AMG package, so big wheels with low profile tyres, which probably is relevant. It's on the original factory fit tyres. They are in pretty fair condition but do have some odd wear patterns on the outer tread blocks.
He's unhappy with it because at low speed (<25 mph) and large steering angles (but not necessarily full lock) the front end "hops" as the tyres stick/slip. This is quite violent and while worse at low speed and very tight angles (his driveway particularly apparently), it also does it during town driving when turning into/out of junctions, on smaller roundabouts and even (around here) on some of the tighter bends in the country lanes. An expensive, near-new prestige luxury car, but definitely not a luxury driving or passenger experience.
Short video showing the problem (our own example is more violent than this)
Or if you enjoy a good rant, the John Cadogan version....
The dealer has told him "they all do that sir, it's a feature, not a fault". Though they are going to try and "improve" it after he threatened to reject it (which remains an option).
From my internet researches so far
- It is a pretty common issue for this model, at least in RHD form. Main complaints seem to be from UK and Australia, but I did find one or two reports of it in LHD as well.
- Afflicts vehicles with big wheels/low profile tyres more seriously (no surprise there).
- Supposedly worse when using summer tyres in low temperatures. This may be true to an extent, but on this vehicle it was doing it markedly at 12ºC ambient, having just completed 250 mile drive, so the tyres were thoroughly warmed through.
- Mercedes themselves suggest "winter tyres" as a cure, though they rarely offer to pay for them.
- Opinions vary as to whether alternate summer tyres and suspension alignment work helps or not. Seems it does for some and not others.
I realise this is something that affects some other vehicles, 2WD and 4WD alike but usually expensive German ones with big wheels and low profile tyres, but I suspect only in more extreme conditions. This GLC seems like a pretty extreme example.
I wonder what the underlying cause is and why the apparent disparity between RHD and LHD. Ackermann angle? RHD having different steering geometry? Possible fixes? Mercedes general reluctance to do anything much about it suggests a proper engineering fix is quite involved and expensive.