I recently purchased a 2017 GLS550 and immediately experienced a significant vibration on the highway around 65-70mph. This seems to be a relatively common complaint on the GL/GLS forums so I decided to do some digging. Much of what I found wasn't new information to these forums but figured I'd add my $0.02 regardless. I'm obviously not an expert so feel free to correct any errors or misstatements.

Vibrations while cruising (not braking) at highway speeds (60mph+) but not tied to engine RPMs seem to often be associated with a tire/wheel issue. Many of the folks reporting this mention having had their tires road force balanced but the issue didn't completely resolve. What I found after talking with Hunter and reading TSBs from several manufacturers about vibration issues is that "Road Force Balance" isn't just 1 thing. For example, when having tires installed locally and paying the extra ~$7-$8 to have the tires road forced, you are typically just getting some extra weights and the tires strategically placed on the vehicle (best tested goes on front driver side, worst on rear passenger side, etc).

What solved my problem was this; find a reputable installer with a new Hunter Elite Road Force machine. This machine has a camera/laser to measure rim runout, older versions use funky manual method that is less accurate. What you want is called match mounting, expect it to be significantly more expensive than the advertised mounting price. Match mounting takes into consideration rim runout and directs the tire to be mounted such that a stiffer section of the tire is mounted on a low point of the rim. This takes much more time to do and involves remounting each tire multiple times at the machines direction as it attempts to get the lowest possible road force reading. It took some time to find an installer with the most current Elite machine, one that had staff knowledgeable on how to fully use all its capabilities and one that was willing to put the time in to get the best possible readings. Matching mounting is built into the Hunter Elite but the installer has to select using it, it appears that they rarely do this due to the extra time needed to: mount the tire, road force it and get the new mounting position, remove it from the road force machine, put it on the mounting machine, deflate, rotate tire to new mounting position, remove from mounting machine, put back on road force machine, inflate, recheck road force, and repeat until the best possible number is achieved. I found an independent shop to do the work, I don't get the sense that the dealer is the best place to have this attempted.

This fixed the issue for me, hope it helps some of you out.

 

Good to know! How much "extra" is this process?

 

It doesn’t cost any extra at many places. It is the gold standard machine for balancing wheels. Many tire shops advertise that they have one and is part of their service for mounting and balancing tires.

 

Thanks!

 

Not sure this is fully accurate, which was kind of my point for this post. Many places have a Hunter road force balancer and some include road force balancing or offer it for a small upcharge. Road force balancing doesn’t mean that they are match mounting your tires, which takes much longer.

 

It’s called “Road Force balancing” and yes it takes more effort than just a standard wheel and tire balance. But when you’re buying a new set of tires, the additional price is of minimal significance. Tire shops advertise that they have a Hunter Road Force Elite as it is the gold standard so it makes sense to buy your tires where they have this machine available. And it’s actually not that time consuming on the Hunter Elite machine. Older machines could also perform the road force balance but the newest machine is faster. If you’re paying extra, you’re paying to defray the cost of the machine instead of the extra minute of time. If they have a Hunter Road Force (not Elite) then you’re paying for a few minutes of extra time.

I’ll add that this makes even more sense on on large wheels with thin tires. I try to get the smallest wheel possible for ride quality but anyone sporting a 22” gargantuan rim should consider this.

 

Not sure which tires you were trying to balance, but the Scorpions were absolute crap and MB were never able to balance them. It's effectively a defective tire design that was never round apparently. Switching to Continential tires changed everything for my balancing, and never had issues in the past 4 years with them. My winters on aftermarket rims are Michelin X-Ice, and they're also perfectly balanced, still after 4 years. Thanks for sharing this information with us though!

 

What may have made the difference was pushing for the Road Force numbers to be 10lbs or less. My understanding is that typically less than 25lbs or 20lbs is considered acceptable, it depends on what variable was used in the machine. The two front tires ended up at <10lbs and both read were a little over 10lbs. To hit these numbers, some of the tires were remounted several times, the worst was remounted 3 times. This level of accuracy is probably what drove the extra cost. The remount process or more accurately "reindexing" does take some time, I watched them do it twice.

I should note that this was with a brand new set of Michelin all seasons, 1 of which had to be exchanged due to an excessive R2H (second harmonic) road force measurement.

 

I had this exact issue after installing Michelin LTXs on my GLS450. It took 3 tries at the dealership till I found a mechanic who actually knew what runout was and how to make full use of the latest Hunter machines to properly index the tire to the wheel. Now all is smooth.

 

Agreed, the problem isn't finding a shop the has the proper equipment, it's finding a shop where the staff will take the time to properly do the work and hit the lowest possible force numbers. After watching my local indy shop do just one "assembly", I can appreciate that its a bit of a PITA as he went through the indexing process several times until the machine reported there was not further improvements to be made. I don't think its realistic to expect this to be done properly for the typical (in my area) $7 per wheel up-charge, I'm guessing that plays into the quality of the results. I agreed to time and materials to have mine done to the best that they could do, it was worth it.

 

I never fully solved this problem. I replaced all 4 tires twice to fix this issue, using different shops each time. I have balanced, road force balanced, alignment done at 3 different dealerships 14 times over 2 years, and other tire shops also over 6 times. I gave it back as the lease was almost up and i got a GLS580 now. I feel really bad for whoever gets stuck with that car next.

I am glad you guys got this problem sorted out.

 

Have this problem with new tires on my GL450 appearance package rims at 60+ mph and I am trading in this week but it seems many places do not have an advanced balancing machine!

 

My late 2016 AMG GLS63 vibrates at highway speeds and it gets worse as I get to 80mph upwards (UK roads), I had the tyres balanced using normal methods and all 4 were 0 0 with only a little weight needed on each wheel.

Only had it a couple of months and it was delivered to me with this vibration that I put down to low tyre treads, all 4 swapped to a spare set of P Zero 285/40/22 M01 i had already, 2018 year made 7mm tread on all 4, balanced up and it still vibrates like mad.

Recently had a coolant leak sorted by a MB main agent who know me well and they know Im particular so checked the suspension and commented that all is fine, so maybe tyre balance maybe drivetrain vibrations?

Im taking it to a local Hunter workshop Monday

 

Based on your experience I was able to solve mine. I recently bought a 2015 GL550 with Pirelli tires. The moment I drove out of the dealership on the way home I felt vibrations. Long story short I went 3 times to the dealership for balancing and road force. They got the vibrations down to something barely noticeable but not acceptable.
the final solution was to get rid of the Pirelli’s and install Continental Extreme Contacts tires. My GL drives Like on a Silk Road now. Pirelli is the origin of the issues.

 

My vibrations went away with the installation of new Michellin PILOT SPORT A/S. My Conti's had worn unevenly, most likely to improper inflation. I will be monitor tread wear across all grooves in each tire to track wear. Really enjoy the car now. Just purchased it used in July.

 

A bit late to post this, but this is definitely not true everywhere. Consider yourself lucky if there is no difference where you are. My local shop advertises different prices for regular balancing, vs road force vs road force elite with match mounting. I was quoted 107.xx for the 3rd option to be done within 10lbs or the lowest they can get it to, road force option was $85.xx and regular balancing was the cheapest at approximately $50.

 

For one or all four?

 

That's a price of 12.50 per wheel, 50 total.

 

It took me a while to post this because my original tires were shot. Discount Tire was able to get me a new set of continentals for ~55% of original price using the mileage warranty. This is my first time working with them.

I got them to do the tire install with ride matching and immediately got the vehicle aligned at the dealership. I would like to confirm that the suggestion by Scttq worked like a charm. I have never experience this vehicle to be so smooth. I keep getting on the freeway expecting the vibration to start once I get to a certain speed and it just doesn't happen. I would give you a wholesome bro-hug if I could. Thank you for the suggestion!

FWIW, Discount tire's default threshold is 15lbs or under for SUVs with low profile tires. They said the wheels were still in great shape and did not have any issue getting it down to under 10lbs. After everything they did for me including working with Continental on the warranty for a set I bought through Tire Rack originally, I think I have found THE tire shop for the foreseeable future.

 

i had obce a Good Year Shop Alignment deal(6 alignments/3years) for 159$. Was happy at the time(for a RX450H lex), found one now for 209$/6. Happy so far with first job on the 17GLS550.
will bug them about this road force, they hace the latest Hunter Elite.
pS: never felt road vibrstions, i ran new tires/ wheels.

 

What are you referring to with the 15lbs and 10lbs?

 

When wheel balancing is done, they don't balance it to the point that there is 0 vibration, although it might be possible on an excellent set. Some amount of vibration/out-of-balance is acceptable and considered within range. This range is defined in lbs of force. The lower this number, the lower the intensity of vibrations. This is how I understand it and was explained to me.

 

Makes sense, thank you!