My 2 cts on this endless topic. I just installed pilot sport s4 on my E43. As many are aware they are regular not run flat tires. These are as a replacement for the OEM RFT Pirelli Pzero that took a beating by a couple of days at the track. I really liked the Zeros but I was ready to try the new king of the hill Michelins. Essentially everyone complains that RFTs degrade the ride, well, I can personally attest that as far as these 2 tires are concerned, the ride quality under normal driving is essentially identical. I havent pushed the tires significantly but the michelins are very grippy which was also true of the Pzeros. I think the best test will be wet roads, where the Zeros could get a little floaty at high speed. Otherwise figuring out the difference among the 2 will take track conditions. However the biggest take home point is simple, between these very high performance tires ride quality is not influenced in any way by being RFT or not.

 

Anyone is welcome to offer on my new Goodyear take offs run flats 18' if you desire in Marketplace. My wife wanted ole Michelin Premier A/S.

 

+1

 

In higher dimensions I think run flats makes less of a difference because of the small sidewall. The difference is probably bigger with smaller diameter wheels with taller sidewalls. When its time for replacement for my primacy 3 I will probably go non runflat because of a larger selection of tyres and lower cost with maybe a slight ride and noise improvement.

 

It seems like it mainly depends on whether the tire is a grand touring tire or ultra high performance tire. The tires I had on my car originally where ultra high performance tires and rode very harsh. Now I have michelin Primacy 3 run flats on the car and it rides nice. Run flats have come a long ways the past few years towards improvement. With me being disabled I'll stick with run flats as I'd be in a bad situation if I got a flat plus with no spare or jack I'd be really screwed.

 

Run flats really show their worth if you have a flat on a busy road. Just keep driving. Without RFs your life is at the mercy of the next person driving along with all their attention on their phone. That would be one of the next 2 vehicles.

 

That sounds entirely reasonable. These are indeed very low profile on 20 in rims.

 

I hear you, there is a measure of anxiety knowing that your spare is a fix a flat and an air pump. The car doesn't have a jack nor tools. I haven't had a flat in years but my wife has had a couple. Just a couple of weeks ago we used the spare on her gls 550. Those wheels weigh a ton! The wheel had seized to the axle so I was going crazy tring to remove it on th spindly jack. My daughter calmly told me, just lower the jack so the rim touches the ground an the weight of the car pops it off..... thanks google I guess 4 years of engineering were money well spent, she may not know what a lugnut is but she can search google with the best out there!!!

 

I like the idea of having run flat tires and a spare tire with tools. Most run flats are only good for about 20 miles when the car is fully loaded. A typical scenario on a trip is where one is beyond that distance from a service garage, Thus a spare is needed.

 

+1

 

I just find world of difference between most RFT's and good NRFT's.

Those who don't notice are just insensitive asses.

 

That's my set up (at least until I wear out the run-flats, and will consider other options).

 

I have the 2017 E300 Luxury version with 17” rims. Love the car and wanted airmatic but it was a car off the lot and there were no cars available for hundreds of miles with it. Run flat tires are only ok in my opinion on perfectly smooth roads.

I just replaced mine with Bridgestone Turanza Quiet Track non run flat tires and a full size spare in my trunk and a 2 ton floor jack under the trunk. I have only had them for a couple days and have driven less than 100 miles but I absolutely love them so far. Comes with 80,000 miles warranty

With only 17,398 miles after 22 months I needed to replace my 2 front tires for over $700. Replaced all 4 from Costco instead for $775. I had purchased the wheels and tires warranty package so I canceled it. They prorated for 2 years, I will receive a refund so it was a no brainer. I am already ahead because I am pretty sure in another 6 months I would have had to replace the 2 rear tires as well. Here is a photo of the run flat tire wall thickness, it’s 1/2” thick and as heavy as lead

 

My main reason to ditch my 7000-mile Goodyear run-flats was that after getting a flat on the highway, about 70 miles from home on a 300+ mile trip, I was able to reach the nearest exit and an NTB a few miles further, only to be told they could not even take the tire off the wheel, let alone replace it with a new tire (or fix them, as run-flats are not supposed to be fixed). I then spent the next 45 minutes calling other close-by tire repair shops and was told the same thing. Also, that I should just find a hotel in the area and get the car towed to a Mercedes dealership or to the closest place that could service them the next morning (it was about 6 pm then, NTB was open until 8 pm), which was over one hour away. Since I really had to be at a can't-miss meeting the next day afternoon, I limped back home through back roads, so as not to be the slowest car on the highway, and did some 75 miles on a 0 PSI flat never exceeding 50 mph. Got back home around 9 pm. I then rented a car near my home, and did the aborted trip in the morning of the next day, making it to the meeting.

Two days later, after I got back from my trip, I replaced the run-flats with regular Michelin Pilot Sport A/S 3+ tires all-around and pump&fix-a-flat kit in the trunk. This was back in October 2018, and the new tires have done great through Midwest winter snow, sleet, and rain, even though my E400 Coupe was built-to-order RWD (all E-classes ordered by north-midwestern dealers are AWD 4Matics, as far as I know). The Mercedes dealership honored the warranty I had purchased on the tires for the one damaged run-flat tire, softening the monetary blow by some $250.
So, while runflats are quite impressive in their ability to let you reach some destination after you get a flat, you will almost always be looking at a full day or more, including hotel and possibly towing, to replace the tire if you are far from a Mercedes dealership. That is just too much for me, but may be okay for others... Regarding differences between the two tires, the Michelins provide a somewhat softer ride, and the steering became definitely more incisive, but the ride with the run-flats was certainly acceptable. OEM size for my car is 245/40R19 in the front, and 275/35R19 in the rear, which the Goodyears were and the Michelins are.

 

I don't see how having non run flats would have helped. The only difference Ii can see is that you would have ended up on the shoulder.

 

I think it was kinda unusual that the place did not work on run flat tires. I think they need to upgrade their equipment. Most firestone/Goodyear places I know have no problem with runflat tires.

 

I've been told by one shop that run flats cannot be repaired. The next shop fixed it in 10 minutes without taking the tire off the wheel. Admitted it was a slow leak and the hole (screw) wasn't near the corners.

 

I’ve had them repairs no problem. As long as the damage is not in the sidewall. Same as non run flat tires. I think some places just want to sell new tires.

 

None of the repair ships in my county will repair RFT's. I polled them all. Fortunately, my local dealer replaced my flats free as a courtesy.

 

Or they have one

 

The wife's car is our first experience with Extended Mobility tires and I have to say that I'm impressed with the ride. Much less harsh than the Conti DWS' that we've run over the past ~500k miles on cars ranging from a Eibach/Bilstein Sport E28 M5 to my current R-Design Volvo. Hopefully no more calls at 0200 when she has a flat at BFE Nevada two hours away from Las Vegas where MBrace says "we don't know where you are, call tow truck".

 

Just noting here and in another similar discussion that I decided on keeping the 20" wheels because they just look so darn good - and went with Michelin Pilot Sport 4S tires. There's a very noticeable difference in quietness. However, very little noticeable difference in ride quality. My guess is that a set of brand new run flats would be so close to the same that it's not worth making the change if your primary goal is a softer ride. For that, you're definitely going to need to get smaller wheels...

 

Hi Sal, really interested if you could compare your opinions and thoughts a bit more on this. Are you saying that the Michelins are significantly quieter?

Here in Oz I've received my MY19 (built March 2020) e300 with 20" AMG style wheels. Agreed that they look good and are fun enough to drive, however due to market preferences the 19" or 18" wheels are hard to come by (and cost big bucks) down under from the dealer. I've felt that the factory fitted Pirelli PZ4 runflats do communicate some road noise into an otherwise very quiet cabin especially on urban streets below 50 mph (80km/h). Are the 20" Michelins giving you a subjectively quieter cabin during city driving? I ask because I'm seriously considering the Michelin Pilot 4S when its time to replace my PZ4s.

Also the 20" PZ4s do transmit shocks from bumps/potholes through the airmatic suspension. I get from your post that the Michelins with more air volume doesn't change this?

 

Ive got a set of 4 Pirelli PZ4 run flats brand new if anyone is interested:

https://mbworld.org/forums/market/809894

 

Ok, so I took the plunge to 18" wheels and fitted conventional Michelin Pilot Sport 4 tyres on them.

I got lucky in that a wheel shop in Sydney AU had a set of 4 18x8J 5 spoke tremolite grey (high sheen) wheels in excellent condition (part no. A21340114007X44). Although this wheel comes standard in base model e300s in the southern markets of the US, here in Oz, they seem to be extremely rare. I bought it last week as soon as I found it and immediately replaced my staggered 275/30r20 and 245/45r20 pz4 rfts on the AMG multispoke rims that come standard down under.

Here are my subjective thoughts (after 3 days driving on the new wheels) since this topic tends to pop up often enough:

Pirrelli PZ4 staggered run flats wore like rubber bands on the 20" AMG (2x 20x9J + 2x 20x8J) rims, especially the rear tires:

Pros:

- On smooth roads and highways (90% of my driving) driving at constant speeds above 60km/h the PZ4s are very good, have low noise levels and are smooth on the airmatic suspension.

Cons:

- On the remaining 10% of roads with the odd potholes, dips, bumps or cracks on the road surface, these would crash through to the seats and steering wheel in an abrupt way. This was especially hard on supermarket/ shopping centre metal speed humps.

- When using Adaptive Cruise Control with Active Brake Assist (which I use a lot in traffic on my commute), the braking would be non linear, progressively intensifying and the car would then come to an abrupt halt with a lurch almost every time.

- Tire noise (and bumpiness) when going over gravel, concrete, pavement or cobbled surfaces is quite noticeable inside the cabin.

The tyres I now bought for the new rims are 4x Michelin Pilot Sport 4 245/45zr18 100Y XL ST. ie non runflat, higher load rating than the PZ4s, same speed rating, "Silent Tuned" and non-staggered across front and rear axle in size:

Cons:

- steering response is about 5% (guesstimation) duller than the 20" wheels with the hard construction PZ4 rfts (see below)

- looks. The 18" wheels are quite shiny and look more bling. Not as understated and sexy as having the multispoke 20" AMGs on. (Some people also don't like the look of larger sidewalls, but this does not bother me as the tyre looks well proportioned to the rest of the car and wheel well).

Pros:

- at 45psi fronts and 45psi rears (tyre shop filled them up this way at first), the steering was as responsive as with the PZ4s. There was a creeping in of oversteer with this setup. The tyres were slightly quieter and the ride comfort was subjectively 3% more comfortable than the PZ4s in this setup when going over cracks potholes and bumps.

- At 37 psi fronts and 39psi rears, the PS4 tyres are optimal for me with the front tyres soaking up the road surface irregularities, bumps, cracks and potholes. The car is very well balanced with just a hint of induced understeer this way. Just the way I want it to drive. It's now about 10% more comfortable on these inner city roads. However on highways and smooth roads (90% of my driving) the comfort is subjectively 3% improved over the PZ4s.

- The P4S tyres seem to be quite sticky and the grip during my normal road and highway driving is great. My feeling (and I could be wrong) is that because of this the rear 245mm tyres seem to compensate for the previous wider 275mm.

- cabin noise level is about 2db quieter (not much but noticeable). More importantly the pitch of the sound is now a deep toned hum, compared to the PZ4s which was a deep toned rumble.

- OMG, the braking! The autobraking is now smooth and progressive in a more linear way with a rounded off halt at the end without the abrupt lurch.This alone is the biggest redeeming factor for me.

- Trip computer Fuel economy is now 9.1l/100km in city driving vs 9.7l/100km on the PZ4s

- subjectively 15% improvement in comfort and noise over the PZ4s when driving over cobbled pavement and concrete. (Although I drive over these sections of road relatively infrequently)

- The vibration when going over bumps, potholes and cracks are very well rounded off and dampened out. This is especially noticeable in the supermarket parking lot metal speed humps. They do not feel hard edged anymore as they did on the 20" rfts.

I hope my subjective experience and opinions help out anyone who is seeking for more information on this issue.