Mike5215

The C was my first experience on run flats so I can't comment on the improvement in ride of the Mercedes extended mobility vs traditional run flats . Obviously a sidewall stiff enough to support the weight of the car unaided even for a short period has to be pretty stiff.

I think in terms of factors affecting ride, wheel size is up there. I bought my C after having a base on 17" for a few weeks and I had no complaints. Later I tested a base on 18" and the smooth ride wasn't there. Couple the 18" wheel size with a lowered suspension in the "Sport" (shorter springs) and it no longer drives like a Mercedes. (Honestly I'm not sure the Sport package is anything other than cosmetic bits and 25mm shorter springs.)

Since I wanted the Sport look, and the base ride, AirMatic was the only way to make that happen. Swapping on the Pilot Supersports made a big difference as well, but 18" on AirMatic in Comfort is a decent ride.

yjchua

I've got 19" rims with Airmatic and it's comfortable.

I'd say the biggest culprit would be the sports suspension.

With Airmatic, it's stiff in Sport+ and soft in Comfort. So you get the flexibility of both worlds, but the maintenance cost could be horrendous (but it's something I'm willing to put up with).

Mike5215

Repair costs aren't terrible for an AirMatic car, and they tend to come in the 60k mile range. If the C's system is anything like the S, typically it's a leaky strut that will fail and a corner of the car collapses. If it's obvious and caught soon enough the compressor survives. (If it's a super slow leak the compressor can burn itself out trying to keep the system pressurized and the whole car drops.)

A strut is around $1200 and there are 4 of them. Compressor is around $700. The other bits (sensors, controller, reservoir tank, valve blocks) I've never had fail so I'm not sure what they cost.

If you bought your car from a Mercedes dealer, at any point before the factory warranty expires you can add a 7/75 extended warranty that will pretty much pay for itself with the first AirMatic failure. Out of warranty you can save a little by buying re manufactured struts from Arnot.

In short, the advantages in ride quality and the flexibility to vary suspension firmness to taste outweigh the potential repair hits. But at least in my experience with 3 S Class, the system will fail at some point, usually without warning, and always outside the original warranty period.

purefunk

I honestly believe its the run flats. I had an 08 sport with low pro's, non run flats, positive toe in the rear (not sure about camber) and it ran smooth; the ride was comfortable. I took a ride with my Mercedes mechanic and he said it was the tires. He said the stiff side wall follows everything in the road and feels every imperfection. He drove my last car many times and took it home once to diagnose an issue. He said he liked my previous car better than the new one, FWIW. He said we should put on non run flats and compare. Hes looking for a set at the dealership to swap all four rims/tires and compare the drive. He also said the electric steer is too sensitive and when the tires follow the road, the electric steer wants to help. Now I may be engineer but not a mechanic, so no clue how accurate his assessment was. But I am going to swap the tires and go from there.

Mike5215

The 205 ride is totally out of the norm for a typical Mercedes sedan. You almost have to evaluate it as a stand-alone product. My guess is they were looking to poach 3 series and Audi 4/5 sales by leaning heavily toward the sporty side of "sport sedan" where they've traditionally hewn closer to comfortable and smooth. There's also a lot more ambient noise in the cabin than you'd expect. A "mini S Class" it is not, for better or worse.

You can approximate the "classic" Mercedes ride by configuring the 205 for AirMatic, keeping the wheel size at 18", and swapping on Michelin Pilot Supersports for the run flats. If you've never run a set I can't overemphasize the effect they have on the car.

My car still gets discombobulated on washboard surfaces where the rear end can't make sense of what the front end is doing but on most surfaces she just glides.

I also did a heavy upgrade to the audio to cover the ambient noise (as well as sound proofing material in the doors) and added a Dinantronics Sport module that gave it a little boost. The extra grunt seems to make the tranny less spastic and the car feels more relaxed as a result.

l3gendary

Yeah I have the 17 base and it rides like a dream!
I've wanted to change rims into 18's but I keep hearing how bad the ride is, and I'm very hesitant. Even though they are run flats, I think the 50 size adds a lot of sidewall where you can't feed all the bumps of the road


I haven't been able to drive the 18 or 18 sport yet, what tire sizes are run on those?

Mike5215

If you think of it in terms of overall wheel diameter, all of the OEM wheel/tire combos are the same. The 17" wheel assembly is the same size as the 18" and 19". You're just trading rim for sidewall.

So the 17" have a sidewall that is 2" taller than the 19". Half of that 2" (1") is under the car as extra "give" to absorb impacts. Likewise going from 17" to 18" gets you an inch shorter sidewall (1/2" less between the rim and the road.

There is no such thing as a "50" size, "40" size etc. The actual height of the sidewall is determined by the tire's width. A tire that's 275mm wide with a 40 sidewall ratio (275/40 18) has a sidewall that's 40% of 275, or 110mm.
(275x.40= 110)

A 225/40 18 has a sidewall of 90mm. Same "40" ratio but different sidewall heights.

Here are the OEM sizes for the base 18" package and the staggered Sport 18".

janusgrimnitz

i have 19s with accuair.. very smooth ride... better than OEM if you ask me...

yjchua

I live in Australia and Malaysia, and extended warranty doesn't exist in both countries

cgw944

I'm about to order a 2018 C300 and got the order guide, 6/26/17 version. AIRMATIC is only mentioned once, as standard equipment on the hybrid. It is not listed as an option on any of the other models. I had planned to order the 18" wheels, but the reviews of the 17" and 18" original equipment tires on the Tire Rack website convinced me to go with the 17" wheels. I was not going to order AIRMATIC anyway.

Mike5215

AirMatic wasn't a very popular option on the C300, so it wouldn't surprise me if they nixed it. I had to special order my 300 to get it. Worth the wait though.

madmax

Glad I bumped into this thread. I have a '15 C300 4matic Sport with the 18'' run flat tires and it is the worst ride I have had so far in a car. My '12 W204 was way more comfortable.
With less than a year left on my lease, I am counting down the days before I send it back.

I just had my B service and got a brand new base '17 C300 loaner. I was it's first driver, it only had 6 miles on the clock when I picked it up. I drove it on familiar roads and the difference in ride quality between that car and mine was like night and day, very smooth. I drove it on roads that normally rattled my bones but it was very comfortable. Also it had no apparent rattles....yet.
Visually my car looks nicer than the loaner but the Sport package and 18'' run flats are a bad combination on this car.

equetefue

I bought my c43 three weeks ago and barely drove it. Swapping the run flats for Michelin PS4S this weekend.

Should make a huge impact for the best

Gungaslow

Unfortunately it won't... slightly yes but huge,? Not even close .. I have the 19s on mine and was hoping for huge

Mike5215

Agree. If you loved the way a base on 17" drove and were thinking the Sport package would just make the thing look sexier (and it does) I can see how people got stuck with a very stiff and unforgiving C300 Sport. Unfortunately the base on 17's is a visual dud. Driving that car would have been like dating a fat chick or riding a moped...it's a lot of fun until your friends see you.

Since there's nothing in the Sport suspension a sane person would modify on a lease other than the tires, my thinking is get the most comfortable riding performance tire you can get your hands on. For me that's always been the Michelin Pilot Supersport.

They do make a difference, and any improvement is still an improvement, but it wasn't until I dropped the PSI to 30 that I felt some of the compliance and creaminess in the C that I'd become accustomed to in my S Classes. BTW, an S will completely spoil you when it comes to ride quality. Once that's your "normal" it's very hard to give it up.

My C does have AirMatic which helps, mainly because I can set the ride height to match the base car. Doesn't look as slick jacked up high like that but I'd rather have the ride quality. On some roads if they're twisty and in good shape I'll drop it to Sport for fun but I always end up in Comfort.

But MPSS, 30lbs PSI, and it'll be a different car. Best $800 you'll ever spend.

madmax

Mike, good to know about the MPSS swap for ride comfort. What do you do for a spare since they aren't run flats?

Mike5215

I picked up a Slime Seal & Fill kit on Amazon for $30. Ironically, run flats have a higher incidence of blow outs (sidewall ruptures) than conventional tires by far but they're better with punctures. I've used the kit a couple of times to rescue people on the side of the road and it works as advertised. My wife just got a new Q7 with conventional tires and it has basically the same kit branded for Audi. No jack.

Not a scientific observation but I've been driving S Classes on MPSS for the past ten years (roughly 200,000 miles) and never had a flat. Which is too bad because the S Class spare tire kit comes with little white gloves so one does not soil ones hands, and I never got to use them in any of my 3 S's.

madmax

LOL on the white gloves and not getting to use them. In the last 10 years of driving I have only had 1 puncture that needed replacing a tire. However, in the last 2 years with my W205 I have had 2 nasty tire failures. Good to know about the Kit on Amazon, I will look into it when I move onto conventional tires.

Steve71

I've been reading through this thread and been a bit surprised. My 2016 C300 (4Matic) base has steel suspension, runflats and 18's. I run at about 36 psi. Except for big pot holes, I find it's a dream to drive.... smooth, relatively quiet with decent handling. So, go figure.... Maybe it's because all of my previous cars have been "sports" models with stiff suspensions so my comparison is only against stiff suspensions. But I love the ride I get from my C.

Mike5215

Perspective has a lot to do with perception. Coming from a series of S Class, a global benchmark for ride quality, I'm probably expecting a lot from the C, although I knew going in it wasn't a full size luxury car. Still, even with AirMatic and MPSS, my C will find any excuse possible to offer a flinty, harsh ride. Only on the most perfect new asphalt does it ride "smooth". I had written it off as a trade off for driving a small sedan.

But then a couple of days ago I rented (and I'm still renting) a new BMW 430 Convertible with a T4, on a steel sport suspension and Conti run flats and that car drives, rides and sounds so much better than my C.

Jesbran Silva

Do you have a part number for the C300 non 4matic kit? thinking of going that route. I have 19" HRE wheels with Michelin Pilot Super Sport tires and the ride is all over the place, super bouncy and loud over small bumps.
Or maybe i'll just get Bilstein B8 shocks since I kept the stock ones after lowering it......

jfz219

Silva wrote the first thread in which I read that MPSS tires were bouncy. I had the same experience with the tires on a 2012 S550. Sharp impacts were followed by two rebound bounces. Setting the suspension in comfort or sport did not change the lack of dampening. Adjusting the tire pressure made no difference. But all is well in the end. After 500 miles of mainly highway driving, the tires perform brilliantly.

Jesbran Silva

Quick update: I set the PSI at 42 front and 45 rear and wow what a difference, the car feels more intact and way less bouncy even though I get some weird feed back from the rear form time to time.

mirkee1

I did some reading on the Michelin site. They suggest or imply that Mercedes are engineered with a particular combination of runflats and special rims. Can I just put non-rurnflats on my stock 17" rims of my 2017 C-300? Do I also have to change rims to accommodate conventional non-runflat Michelin tires or can I use my existing rims?