Hello!
I just picked up my new (to me) 2021 C300 last week. I noticed that the ride was a bit on the harsh side and I was somewhat disappointed as I had expected a Mercedes to have a more refined/luxurious feel on the road. Then I discovered that the car came equipped with run flat tires (I discovered this when I asked the sales rep why there was no spare in the trunk). I am considering purchasing regular tires and am wondering if the car's ride would be improved enough to justify the expense. Does anyone have experience and/or opinions on this?

 

An absolute resounding yes, it will improve it.

 

I'm looking at the options below for max luxe and comfortable ride. Please weigh in:
Michelin Pilot Sport AS4
Michelin CrossClimate2*** (lots of folks seem to love these)
Michelin Premier A/S
Michelin Primacy
Michelin Pilot Sport 5
Pirelli Cinturato

 

If you live in an area that snows, you could get one of those all weather tires (not talking about all-season), otherwise get a set of winters and a set of summers for no compromise in both conditions.

 

Depends what size ur tyres are, I have 35/245 R20 and I find them to hard, after hitting a pot hole or 2 at speed I had found a few cracks in that wheel, my next tyres are going to be at least 45mm in height

 

Go with these unless you already bought something. I purchased my 2021 C300 last Summer. They installed brand run flats as part of the CPO. After the first 100 miles I was buying new tires to improve the ride and noise. The tires below get great reviews on TireRack. I have been very pleased after 5k miles.

Pirelli P Zero AS Plus 3

Regards,
Craig

 

Hi Craig,
Thanks very much. As it happens, I purchased a set of Pirelli P7 AS Plus 3s a few weeks ago due to the harsh ride of the run-flats. I'm not sure how much they differ from the Pirellis you bought. I have to say that, although there has been some improvement over the run-flats, I find the ride to be very...unrefined. It's pretty disappointing. I'm not looking for the car to drive like an ultra-cushy 1970s era road yacht but the way that the car transmits every irregularity in the road is very harsh and unforgiving and not at all what I was looking for in a luxury car like a MBZ. BTW I always have the ride mode set to "comfort". It may sound strange to say but my trusty old 2007 Saab 9-5 Aero (which the C300 is replacing) handled road irregularities with far greater aplomb then the C300. Perhaps I should have gone with an S-Class or E-Class.
Cheers,
-David
P.S. Since the C300 doesn't come with a spare, what do you have on hand in case you get a flat?

 

How are the tire pressures? Use the ones on the fuel cap door measured when cold like sitting overnight.

 

As for fixing a flat, you usually buy the Tirefit kit from MB or a slime kit from the aftermarket or something.

 

P7 is vastly different than the P Zero. P Zero is # 1 all season tire on Tirerack site from all the users comments and is the top in comfort and noise. Drastic different from the runflats prior. Car is super stable, rock steady, handles well, more compliment, and quieter.

 

Use fix a flat for your spare and carry a tire air compressor. Not concerned about no spare vs a run flat. Car is used for city commuting and not a travel car. I can make it to any tire shop in a pinch since there are so many in Dallas. I am willing to roll the dice.

 

Also...the pressure on the fuel filler flap is for run flats at 37 PSI. Run flats run at higher pressures. I am running mine at 34-35 cold which tend to warm up to 37 - 38 when driving. At 37PSI cold in the Summer they were still too firm since they would heat up to 40-41 PSI.

Thx Craig

 

Thanks,
I have been running the tires at 38 psi cold. I read your other comment that the recommended pressure on the fuel cap is for the run flats so maybe I'll take the Pirellis down to 35 or 36 and see how they feel.
-David

 

Yes. Definitely play around with the tire PSI to see what feels good.

Craig

 

Hey Craig,
I dropped the inflation level to 35 psi on all four tires and it DEFINITELY rides much better now. Not ultra creamy but very much improved.
Thanks very much for that suggestion!
Cheers,
David

 

On my e modal I switched to continental tires and reduced air pressure 2 psi. Much better ride. Also got small spare from Modern Spare. MB is not an isolated ride experience, road feel means you get to feel the bumps too. You might be able to get smaller diameter wheel with more rubber. That is the next step I'm considering.

 

Thank you! Do you have a link for Modern Spare? I asked my dealer if they sell "donut" spares but they do not. I bought a can of the Airman ResQ stuff but I would feel much more confident having an actual spare on hand.

 

https://modernspare.com/product/2017...e-kit-options/

 

My X7 came equipped with staggered 22" performance (e.g. "summer") run-flats, and I swapped them out for a set of 20" wheels and A/S tires, not because of ride comfort, but for convenience. We use the X7 mostly for road tripping in the rural west. A run-flat is fine if you're 3 miles away from a tire dealer that stocks odd-ball tire sizes, but getting stuck in Elko, NV for a week while a replacement tire gets express shipped in from the east coast is not my idea of a vacation.