Home · 2021 Mercedes-benz S-class Phev · Complaints

What 33 owners told NHTSA about the 2021 Mercedes-benz S-class Phev

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (33)Crash / fire / injury (4)Electrical system (10)Wheels (6)Driver assistance (5)Engine & cooling (5)Brakes (3)Engine (3)Lane Departure (3)Speed control (3)Communication (2)Fuel system (2)

6 of 33 complaints match · Wheels · clear filters

Jan 13, 2026Wheels

Three wheels had rim a total of eight cracks that lead to one tire unable to hold air. Loss of air in tire can lead to crash. Mercedes service inspected car after first crack was noticed by Discount Tire when they diagnosed deflation in tire. Mercedes service reported that two additional wheel rims were cracked. Discount Tire subsequently determined a total of eight cracks and took pictures. Mercedes service representative stated that initial OEM wheels on 2021 S Class were weak and frequently failed. Service manager said they have had cracks during test drives from simply riding over a metal plate on the road. Car was bought used with 22k miles and driven only 3k miles by me at time of failure. Car was supposedly 100% inspected and was “certified”. Low air pressure indicator alerted the issue.

NHTSA ODI 11710678

Jun 25, 2025Wheels

Excessive Tire failure on "AMG" 21 inch wheel and tires. Pirelli tires have replaced 4 tires in four months. cracks in side wall bubbling.

NHTSA ODI 11669111

Feb 20, 2025Wheels

I purchased this vehicle used at a dealer in Virginia. I drove it home to Chelsea Alabama, outside Birmingham. After a couple of days, my front right tire went flat. I took it to the dealer and they said the flat tire was caused by a cracked rim and required both to be replaced. Almost $3,000 for tire and rim. I continued to drive the car, maybe 4,000-5,000 miles and I had another tire go flat. This was the drivers side rear tire. This was a Pirelli 285/35 R20 run flat tire. Again when I took it to the dealer, this rim was cracked and also needed to be replaced along with the tire. $2,790. The car has 55,000 miles and is meticulously maintained. And I do not drive on rough roads. The dealer consistently states it was due to “hitting a pot hole” which a) is not the case in both these incidents, and b) a rim should not break from running into regular small imperfections in the road. I’ve been in the auto manufacturing business for 38 years and have never, ever had a rim fail, not once but twice in 4 months on the same vehicle. After investigating, this is happening all over. My feeling is the rim has not been sufficiently designed to support the weight of this vehicle. And now, every time I take the car out, I fear for my life and my families life. Frankly, the car is not safe because the rims can and will crack and split under regular driving conditions! This can cause a blowout and possible injury or death. This cost and the cost of my safety should be covered by Mercedes. They should replace these rims with stronger, more properly designed rims to ensure my families future safety!

NHTSA ODI 11643990

Feb 18, 2025Wheels

I’ve had to replace six tires due to blowouts from hitting small potholes, something I’ve never experienced in the past 40 years of driving other vehicles! This seems to be a manufacturing defect in the vehicle, as the tires can’t support the weight of the car, and any pressure on them causes them to blow out. I’m now hesitant to drive long distances, fearing that one or more tires could blow out at any time. Without a spare tire in the trunk, I’m left stranded. Below are answers to your question: 1. The tires failed, yes they are available for inspection. Also have photos of the damaged tires. 2. The safety of myself and my passengers is at risk, as a tire blowout while driving at 55 mph could potentially cause the vehicle to lose control and result in a serious accident.. 3. The problem has been confirmed by an independent service center. 4. The vehicles tires have been inspected by an insurance representative and independent service center 5. NO

NHTSA ODI 11643496

Jun 12, 2023Wheels

I have had one tire blow out after traveling over a moderate pot hole, and 3 other tires that have been damaged with "bubbles" due to excessive stress from normal driving. In addition to the damaged tires, I have had 3 bent wheels all due to normal driving because the 21 inch wheels/tires on this vehicle cannot tolerate the loads during normal driving. This is a well-known defect by Mercedes and I believe it is a design defect and that it is dangerous.

NHTSA ODI 11526539

Jul 26, 2022Wheels

I have had 3 tire failures(blowouts)when I have hit potholes with my 21” wheels and Pirelli P Zero tires. I read on a MBZ Forum for my specific make of car - 2021/2022 MBZ S580 - that many others have experienced the same failures with these Pirelli tires. Those that have Michelin have had none. With such a small area between the road and the rim afforded by super low profile 21” setups, a tire like Pirelli with a weak sidewall will fail when the car strikes a pothole or obstruction. Another owner on the Forum said when he contacted Mercedes, they said it was not their problem, but Pirelli’s. Meanwhile, there are thousands of owners with this combination, many of which have already experienced failures. Something needs to be done before there are injuries, or worse.

NHTSA ODI 11475880

Working with the data? Download all 33 complaints as CSV · fetched from NHTSA July 20, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2021 Mercedes-benz S-class Phev verdict →