I have a 2021 GLS 63. It is my latest MB SUV. I find it to be an outstanding vehicle in every way. But that all depends on how you use the car. I use my car daily for a variety of regular functions. My Porsche 911 track days are in the past. I carry everything from people to airports, to groceries, to spare motocycle parts, to bicycles to two large Ridgeback dogs. I love the car because it is fast, it is quiet, it does everything well. On the highway I use it in Sport Mode. It carves thru traffic and is always an impressive sight in someone's rear view mirror.

I ordered the car with the Ceramic front brakes, 21" wheels and in Cardinal Red. The brakes are fantastic with great feel, and the 21" wheels and tires give me some rubber between the wheel rims and the road. The roads in CT are in terrible condition and it seems foolish to choose "cool looking wheels" over usability.

I enjoy the longer wheelbase, more legroom, and the overall more luxurious interior. The lighting and computer and GPS systems are all superior. The other SUVs I have driven are all too small unless one only cares about profiling. The larger SUVs from the US are all too truck like.

The ceramic brakes are simply outstanding. I see that they are becoming more common now. on other brands.

There are few tire choices for the 21" wheels is the only drawback. I used Pirelli Scorpion Winter tires for the winter season.

I don't have any real criticisms that make me regret choosing this car.

I had to replace the 48 volt battery in the first three months but that is the only "fault" I have experienced thus far. Oh, and I had to replace the driver's seat belt reel. There have been two recalls I believe.

I plan on keep the car for a long time unless there is a better GLS coming next. But without a V8 I doubt that is possible.

 

Mine is starting to sound a little louder than it did when I got it, not sure why but happier for it.

Mercedes did an engine software update a few days after I got it, not sure what but it was an outstanding recall maybe that made it quieter initially?

I still got too much body movement, twitchy back end and it tramlines like crazy but I do agree the lighting, tech, space etc are much great even if the build quality on mines a bit off. Latest issue is a regular alarm system malfunction error message when driving along.

I know it’s a big 3 row and I’m not expecting sports car like ride, I drive a Range Rover Sport SVR recently, a much smaller car, but the handling was way more composed, not as fast as the GLS but just more composed, no twitching no tramline effect no body roll and about the same maybe a slighter firmer ride, but it was on 23” wheels.

I watched a YouTube video about the facelift GLS that’s coming, and the journalist here in the UK said 2 things I experience with mine, it feels like there’s a crosswind pushing at the side of the vehicle when driving it, and it seems to get a bit skittish when it hits less than perfect roads (which we have a lot of), that was a brand new car, so I’m not sure if it’s my tyres, or just the set up of the current GLS not working that well here in the UK?

Im on the edge, change all the tyres to see if it improves the ride or cut my losses but the losses will be around £30k GBP in 3 months if I do put it back in.

 

I'd start experimenting with tire pressures before writing off 30k.

I'm assuming you're using the correct pressures, which are on the gas flap, not the door post or Tire sidewall.

Start there, go plus or minus 2 lb, then 4 lb and see where it approves, if at all.

Wide tires tend to tramline, and some brands are worse than others.

It'll take some time. Spend a day or two with each setting and analyze.

Let us know your findings.

Edit: dealers are unreliable in setting their tire pressures, so I always take my tire pressure gauge along when test driving. It makes a big difference. The sales people are often surprised at how far off the tire pressures are when I do that, as they sit there patiently while I inflate/ deflate tires.

 

I’m running 37 rear 39 front on winters on summer 23s it was 35 rear and 38 front.

Also would suggest 4 tires of same manufacture and type. I’m wondering why you had a mixed brand set upon purchase?

Different brands and types even with brands have different rubber compounds and sidewall flex. That will lend itself to instability in road feel. I’d also have them check for road force prior to unmounting.

When I have seen mixed brands I tend to think damage and taking a less expensive solution. Given dealership lack of attention to detail at times, I’d go with an independent MB specialist.

Even in my softest setting I’m not getting the crosswind or tramline feelings even on my 22’ winter setup of Pirelli tires.

 

For reference, I use the same difference between my Summers and Winters.

I'm at 41F/37R +/-1psi on my Conti 21's.

 

Im running 34 front 33 rear so a fair bit lower than you guys are, here’s my petrol cap label which has 31 front 31 rear on lighter load, which seems low for such a big powerful vehicle with wide tyres

 

The rears were changed, whoever did it before me didn’t go like for like brand but did get MO,I guess it was based on availability on the day, and not really caring to go matching

 

Even with an MO that does not necessarily make it compatible (compounds and traction) with different tire brands with MO markings as well.

 

Interesting. Mine are a bit higher.

 

I agree with you, I need fronts now so will fit Conti to match the rears if I keep it

 

Another note. Is it possible you may be thinking it’s tramlining when it is infact following a rut or depression or even a larger crack.

all my sport-type SUVs with stiffer suspensions as well as my M5 and Porsche all would track (almost felt like wondering) when finding a rut/depression in road/or wider cracks. Particularly here in Colorado on I70 by our beloved tunnel nearly all my tight suspension cars would wonder as one side of wheels/tires found that groove worn by chains from larger trucking rigs.

it is a characteristic of stiff suspensions.

 

Yes thats definitely something I feel, roads near me have a lot of grooved roads typically on the inside lane caused by HGV’s etc and the GLS gates being in those ruts, but, it still wants to wander a little when on better roads, like tyres are rolling on the treads for example

 

Not sure without looking it up but there were on my X5M and W12 a requirement that all tires were within a certain limit of wear. This was to assure its AWD worked properly and prevent damage. Had to get this checked once after a blowout from a pothole. Luckily was with tolerance with only 4k mileage.

Again have not checked this AMG GLS.

 

I'd be surprised if your car didn't behave strangely, with mixed front and rear tires.

Also, to be more specific, AMG tires have the MO1 designation. One step beyond the MO base designation.

In either case, it indicates a collaboration between the tire manufacturer and Mercedes.
If that's important to you, then look for some MO1 tires.
I think it's important, and I have actually found them to be cheaper at times.

 

Exactly!

Extreme Example: Put a set of tires in the front with a 200 wear rating (sticky), and some 480s (less sticky) in the rear, and the back end will be trying to pass you every time you turn or stop.

 

Here's a good video talking about MO vs the non-MO.

 

Looking around here in the UK the choices are really limited so I assume that’s why the vehicle ended up with MO rated Conti Premium 6 on the rear before I purchased, and the Yokohama MO1 are on the front, but do need to be changed soon as the outer edges have worn, centres are ok still with just under 4mm left but outer edge is worn.

Its always felt compromised during my ownership and the Carlow video I watched recently on the new facelift 167 talked about the crosswind like feeling and skittish behaviour on that car so I didn’t think just my tyres when a new car with 23’s was doing it too.

For me Michelin PS4 is the best SUV tyre and it’s neither MO or MO1 but not even sure it’s available in the 22” rear size, it’s a bit crazy for choices actually

 

For those running higher pressures than me what size wheels are you on and what does the petrol cap label say recommended pressures are please?

 

So I asked my Merc dealer near me, they dont offer the rear tyres at all, and would need to special order the fronts but cant get Conti to match the rears, so I’m thinking this is why I have mismatched tyres, lack of choices here?

Bit naff that the franchise dealer network for the brand doesn’t sell tyres for it, but Im not that surprised really.

 

They probably do sell tires for their cars, but availability is often a problem. Especially for winter tires, seasonally.

You can't expect a dealer to have every tire for every model ever sold, in stock. Even specialty Tire stores will probably have to special order your tires.

An owner can buy any tires they want, but it's up to subsequent owners to make sure that they are correct. Or live with them.

Often that availability problem forces you into tires that you may not want, especially if you have a problem on the road.

It could be worse. You could be forced to buy the Aston Martin spec tires which are over double the price for the same size tire with MO spec.

 

Sorry I mean they said they do not sell them, they said it’s because it’s a large size tyre, so I have to buy elsewhere.

They could offer a tyre for the front but on special order only.

I dont expect them to hold them in stock but did think it reasonable that the brand sells tyres for all of its cars.

 

This is a major reason why I won't spec wheels bigger than 21". I would have even avoided 21" had I known it would be a staggered setup!

 

I agree, but 20 inchers aren't enough tire for that car.

Further, I don't like staggered because of the inability to rotate tires.

Even further, my car needs more front tire to balance the rear traction in the twisties.

It'll probably cost me several thousand dollars over the life of the car, because of the staggered setup and the differential wear, but that's what I signed up for so I'll live with it.

 

My GL450 had 20s and it was great. It may not have been as stylish as the larger wheels but very reliable and stupid easy to replace!

 

I agree.
My 2020 GLE 450 also had 20's.
They seem well balanced, but not up to the performance potential of the car, if you wanted to push it and have some fun.

Even that 5,000' elevation, I'd spin the wheels from start, if I had to launch into a gap in traffic. Traction control would kick in.

Most people don't push their 450s that hard. I probably shouldn't either, but I'm on my third childhood....