Cambridgehank

I just replaced the Goodyears with Primacy Run Flats. You are correct the ride home on the highway was so much better, I am liking my car again.

2012 merc amg

Thats great. I am very happy with the Michelin Primacy Run Flats. Could be that a tire like the Bridgestone Serenity non run flat rides a little better but I'm just not willing to risk a flat with no jack and spare tire and don't want to take up the space to have them.

IronBallsMcGint

Thanks for the post. Getting ready to replace the tires on my 2017 E 300 and saw this. I am currently riding on the Goodyear RFT. Would you ind sharing if you are still liking the Michelins and how the tread wear is going? Thank you.

ua549

Later today a set of Pirelli Cinturato P7 All Season Plus II non-RF tires is being installed on my E300. They are 70k UTQG 700 A A rated. My local Mavis dealer beat the Tire Rack price significantly. I used Michelin tires for several years, but the last sets suffered from extremely poor mileage. Long story short I bought 4 tires and Michelin gave me 12 tires. None of the tires lasted much more than 5k miles of 100% city driving.

JTK44

Again just my $.02:

I really cannot understand any tire, I repeat any tire lasting only 5,000 miles - never mind a Michelin.

My Pirelli P7 RF have 9,000 miles and based on the tread left, should be good for 28,000 to 35,000 miles. I diligently monitor the air pressure which I keep at 35 psi, front and back.

I have standard 18 inch wheels on my 2019 E450.

The_Judge

I love these tires! Far superior to the RFTs that came with the car when it comes to ride, handling, and noise level. I've only put about 3000 miles on them, but so far the tread wear seems negligible. BTW, I keep them inflated to the recommendations found on the gas-tank flap.

ua549

In over 50 years of driving I've never come close to the advertised mileage regardless of brand. The RF Pirelli Cinturato P7 OEM tires have less than 13,000 miles on them. All are worn evenly and have been rotated twice. All of my driving is in the city at a max of 45 mph. I'm a very conservative driver. That said I replace tires when they are down to 3/32" of tread. Most new tires have 9/32" tread. IMO city driving is much harder on tires than highway driving because of stop/go cycles and many changes of direction.

e400c

My cautionary tale is from the opposite point of view. One of my 5000-mile RFTs got punctured in a similar manner (probably some big diameter bolt) 70 miles away from home, except it could not keep full pressure for more than 3-4 minutes. While I was able to get out of the highway and reach three different shops (the one thing RFTs are great for), including an NTB, none of them had equipment to even remove the tire from the rim (so there was no option of replacing it), let alone to provide a temporary patch.

Tried using foam, but the hole was too big, so the only option other than find a hotel was to limp back home 70 miles at some 40 mph. Had it been a regular tire with the same exact puncture, I would pretty much still have been able to reach NTB on those same 3-4 minutes, get it patched for $20 and do the rest of the 300 mile trip I was in the middle of.

Because of the stupid RFTs, I had to drive 70 miles for 2h on an empty RFT tire that could have disintegrated at any moment, rent a car as early as possible the next day (some $150), drive the 300 miles and barely make it in time to the event I was attending and could not miss.

So, 3 days later, replaced the RFTs with non-RFTs Michelin Pilot Sport A/S 3+ at a cost of $1100 (would have been $1400, but the Mercedes tire warranty covered the one damaged tire replacement), bought a pump+foam kit and have been totally happy since, and midwestern urban roads are not particularly pothole free...
Only annoyance is a too quick for my taste tread wear, even though I do not drive my E400 Coupe that hard, but otherwise they're excellent tires and better in any way than the RFT Goodyears they replaced.

So, the cautionary take of this story is that if you have RFTs and are far from home when one of them deflates, you are looking at a hotel for you, a truck bed for your car, and 24h lost instead of 30 minutes patching a regular tire.

JTK44

I do not follow and perhaps you can explain:

If the places you stopped at could not remove the RF to patch it, how would they be able to remove a non run flat? There is nothing special about removing and mounting a RF vs. a non run flat.

If the hole was too big that the foam could not fill it, I doubt you would have been able to patch it or a non run flat for that matter. Either way you would have had to replace the tire. With a non RF, you may not have been able to go even the 3 to 4 miles to the first shop.

You do know of course that like a non run flat a run flat can be patched, correct?

As I see it the biggest problem with a RF is a sidewall failure or a large puncture: When that happens with a non run flat you just replace it. With a RF you also must replace it, but will have to probably wait as RF are usually not in stock.

ua549

Actually it takes special equipment to mount/dismount run flat tires. Even the local WalMart won't touch run flats. In my area tire shops will not repair run flats. Period! I had a run flat failure and it took 5 days to get a replacement tire. Today I purchased a set of non run flat Pirelli tires. Not only do they ride and handle better, I have the peace of mind that comes with being able to get a flat repaired almost anywhere. I also purchased a compact spare.

IronBallsMcGint

Thanks! Sounds like I’ll be getting a donut to toss in the trunk. Great story.

JTK44

Dear UA549:

I have never gone to Walmart for my tires. I use Mavis or Goodyear. They have no problem with taking off and putting back on RF.

Sorry, but whoever told you (was it Walmart?) that you cannot patch RF, is wrong.

There are prior threads on this subject and each tire manufacturer has different standards: Pirelli permits patching and/or fixing.

Good luck when you have a flat in your non RF, and it is raining or cold or a snowy night and you pull over, open your trunk, look for the jack, jack up the car and replace it with your doughnut. I for one would rather just drive on my RF to the nearest gas station and have the tire fixed.

Here is my plan: I have a high quality air inflator in my trunk: if I get a flat (not a blowout) I will monitor the tire pressure on my dash, and as the psi goes below 25 psi, I will stop and inflate the tires to 40 psi, continue driving until I get to shop that can patch the tire. As long as there is pressure in the RF, it can be patched and I am on my way.

If you have a blowout with non RF, you are stuck: With RF you can drive up 70 miles. Either way the non RF and RF must be replaced. At least with the RF you are not stranded!

That seems much better than having non RF, jacking up the car, removing the tire, replacing it with a doughnut, etc.

ua549

Actually it is a Pirelli policy to NOT repair run flat tires. When I had a flat (I've had 2) Tire Kingdom refused to repair a simple puncture through the center of the tread. The first time MB replaced the tire on the same day (Saturday) at no cost. The second time I had to wait 5 days. If I have a flat my roadside assistance will come and change the tire at no cost and/or repair the tire on the spot. The alternative is an overnight hotel stay at a minimum. According to the MB Operators Manual a loaded vehicle can go 19 miles on a flat. A lightly loaded vehicle can go 50 miles. Personally I can verify that the 50 mile range is overly optimistic. 30 miles is how far I traveled before the flat tire shredded. I was in the Everglades and waited 5 days to get a replacement. I would much rather have a spare tire onboard and a tire that can be repaired at any shop or by a roadside assistant,

rraisley

If your RFT was punctured and would not keep full pressure, why were you bothering to stop to inflate it? It's intended to "run flat", that is, run with no air in it. I'm not saying that's ideal, or even the best way, but it's designed to deal with, at limited speed and distance, exactly what happened to it. No?

JTK44

If you do not keep it inflated, then the tire will run on the sidewalls and once that happens for any distance the tire must be replaced. If it is a small leak, you should be able to keep it inflated, not ride on the sidewalls, go to a service center and have it patched.

The main benefit of the RF vs. non RF, is in a blowout: with a non RF you are stranded: with a RF you can continue, albeit at a reduced speed, for up to 70 miles.

Also with a small leak your chances of making it to help are far greater with a RF than a non RF.

e400c

Because of how the RFT fits the rim, they were all pretty adamant you needed a special tire remover for RFTs. They certainly had the regular one to remove non-RFTs. Thinking back, I see no reason why they would not want my business, I offered to buy a replacement tire for $250 on the spot, but they said they could not remove the tire and nicely inflated it for me, which gave me about 3-4 mins of driving at more than zero pressure.
One of them told me the closest place he knew where it could be done was some 40 miles away back up the highway, but by the time I'd get there it would be closed.
How sure are you of your statement that there is nothing special about removing a RFT vs a non-RFT? If you are absolutely sure, then I guess these people were all having a cheap laugh at my expense, which makes the story even worse...

I had absolutely all intentions of replacing the tire on the spot, but no one would do it because they had no equipment to remove the RFT from the wheel. I've had two punctures in my life before this one on regular tires, they were patched and solved in 20-60 minutes, one of them involving fix-a-flat and a 20 mile drive in a pretty remote place. Fix-a-flat would have not solved this particular one, but for regular tire shops not to be able to replace an RFT at all was a very cruel novelty that will make me never have one again in my cars.

Most RFT manufacturers do not recommend patching a RFT, but that is irrelevant to anything I said in my post, since the RFT could not be patched or replaced because removal from the wheel was not an option. I could perhaps have bought a rim+tire, but I did not have place to store the 19 inch rim with a 275/35R19 tire on it in the car or in the apartment I was renting at the time, so trying my luck and driving back home ended up being the only workable option.

Fair point, and I assumed as much, but the inability to get the tire replaced on the spot was a very unpleasant surprise.

e400c

I was trying to get it inflated to prevent it from overheating and disintegrating while driving back the 70 miles. After the 3rd or 4th inflation, and the failure of the fix-a-flat to keep any pressure (the hole was right in the middle of the tire and I could hear it hissing as I inflated it), I gave up and just monitored the temperature of the tire for the next 2 hours to make sure it would not go much above 110 F (If it did I'd slow down the pace). Not sure if 110 F was too high or low a temperature, but all other tires were at 70-80 F, so I settled on that as the limit. I even took a picture of it (sorry it's blurry). It was great that the E-Class has a real-time tire temperature monitor, by the way... The other very useful tool was to set google maps to avoid highways, so that I would not be a danger to everyone else driving 70mph+ on the highway. The total distance ended up being pretty similar and I was doing 35-40 mph anyway so local road speed limits were not an issue.

JTK44

I just found this very interesting article, which is pretty definitive on the subject of whether a RF can be repaired or not and whether the average tire shop can change a RF.

My own opinion as RF become more common and appear on more cars, Cadillac now uses RF, many of the problems previously encountered will disappear: If you have a flat and do not drive on the RF, there seems to be no reason why a RF cannot be fixed just like a non RF. The problem is driving on the RF: once that is done the integrity of the sidewall may be compromised. In such an instance the tire upon being repaired may look fine, but its structural integrity may have been compromised, in which case the tire should be replaced. If you drove on a flat non RF, it would of course destroy the tire as well, and the tire would also have to be replaced.

That is why I keep a tire inflator in my trunk and hopefully I can keep my Pirelli RF inflated so as not damage the integrity of the sidewall, drive to a service station and have the RF repaired.

From he article:


“In certain instances, a run-flat tire can be repaired, provided it meets specific guidelines,” said Saul. “These guidelines are contingent upon how far the run-flat tire was driven at low inflation conditions, the amount of air loss experienced and the overall condition of the tire. A run-flat tire that has experienced a puncture or loss of pressure must be thoroughly inspected for any resulting damage to determine if it can be put back in service.”

“For the tire changer though, that extended hump makes it even harder to service. That’s because the already stiff tire needs to be pushed even further down to be in the drop center for demounting or mounting. Many technicians miss this and end up struggling with the tire that they could easily service if they pressed a little more on the key points with one of the press arms I mentioned earlier.”

For the entire article see: https://www.fleetfinancials.com/3213...run-flat-tires

The_Judge

Life's about choices. In this case, it's having the security of knowing that you can drive a few miles on a moderately damaged RFT vs. the better handling, ride comfort, and noise level of a non-RFT. It's sorta like deciding to follow a strict vegan diet vs. enjoying life. I opt for the latter. YMMV.

jhpmbusa

Long story short - its all where you are when it happens and on which day. You can have RFs on a weekend evening, when all shops and dealerships are closed and you are ultimately screwed if you are far from your final destination. Thus you are stranded in a hotel. Plus if the hotel isnt x miles away from a benz dealership or your choice of tow - i believe you are only covered X amount of miles.

So if your RF blows on you Saturday evening when you are out - you are not going anywhere till Monday morning with a tow truck... a horrible situation which practically means you blew through your weekend and possible a day at work! On top of that, better hope they have your RF in stock!

I would rather have non run flats with a spare any day. As mentioned in my other post - a click of the SOS button and a MB tech will come and change the tire out for you.

JTK44

I think, and I have posted on numerous other threads, that the best solution is a spare tire. For many of us, giving up the space in the trunk, plus the extra cost (I lease) does not make having a spare a practical solution. I even checked to see if a doughnut spare would fit in the well of my trunk and the answer is no.

So yes, non RF with a spare is probably better than RF without a spare: What would clearly be best is RF with a spare which is an option with BMW and only $150 extra!

nycebo

For the record, I have been to a couple repair shops that wouldn't remove my RFTs either when I wanted to swap in the non-RFTs. In the end, I pestered my Porsche shop to do it for me. His mechanic *****ed and moaned before doing it and then *****ed and moaned a TON after doing it. I've been bringing them donuts ever since.

ua549

Yesterday I changed from RFTs to non-RFTs. Immediately I could tell the difference in ride and handling. With the compact spare pushed all the way forward and left, I still have room for 2 suitcases and several duffles in the trunk.

2012 merc amg

Seems pretty rare where you get a flat on the road with major air loss. The typical scenario is a nail or screw in the tire with a slow loss of air where the light comes on and you can still drive the car to a repair place as it's such a slow leak. I did have it happen last summer where I got gash in the side of a tire (run flat) from some metal debris on the road and it was sudden leak and the run flat did save me and was able to drive to the shop on a flat. But that was the first time of that happening in over 30 years of driving and I drive like 30K miles a year.

ua549

FWIW in over 60 years of driving and at least 1 flat per year, I've never had a "slow" leak. Typically I run over unavoidable road debris and the tire goes flat instantly. I'm more comfortable with a spare tire and a service guy that can mount the spare at the touch of a Mercedes help button. I would rather have a tire repaired than purchase a new tire that may take many days to obtain.