You are correct: I quoted those fly by night, never to be seen again, your eyeroll, Edmunds and US News and World report. I thought they were pretty substantial.

Here are few others:

https://www.autoweek.com/car-life/a2...and-tradeoffs/
https://www.autoguide.com/auto-news/...-buy-them.html

Yes I have seen a blowout and watched the tire fly across the road. I have mounted tires and it is stretching process, originally done by hand now by machine. Not that much force is needed. I have no idea what you are talking about "tremendous pressure being used"..

Suggest you look at the OP's picture: the tire is still on the wheel and the car can still be driven. The tire did not disengage from the wheel, and the wheel is still intact. That would not have been the case with a non RF.

As to cost: The delta between RF and non RF remains, whether you buy 1 or a 1,000 tires. RF regardless of the number bought, are more expensive than non RF.

Follow the money: I always try to: Please post the link that supports that RF vs. a spare is a cost savings.

The use of RF predates the hybrid versions of almost all cars. In a lot of hybrids, the batteries intrude into the trunk and take up space, for example the Ford Fusion, BMW and Mercedes.. Very few hybrid batteries fit into the well where the spare used to be.

I have not seen a German car have a blowout and why is that relevant? Is there something unique about a German car that when it has a blowout it behaves differently from other cars?

Finally, I personally would like run flats and a spare. This is a $150 option on the 5 series BMW. I wish Mercedes had the same!

 

Because I travel to Vermont for skiing and the closet Mercedes dealer is 2 hours away, I would prefer non run flats with a spare to RF.

However, as I have posted to save weight and improve EPA MPG, Audi, BMW, Mercedes, Cadillac and most other luxury manufacturers have gone to RF. Their thinking is also that the majority of their buyers will not stop to change a flat with a spare. Those of us who are willing to do so are out of luck.

As to ride quality: I have the standard 18" wheels and Pirelli P7 RF and I find the ride smooth and quiet. If you go to a larger wheel, with a smaller sidewall the tire will be stiffer whether RF or non RF and the RF will be stiffer than the non RF.

If you go to other posts where ride quality is discussed, the vast majority of complaints are from owners who have "performance wheels".

 

Eventually, I'm going to discover these things myself.

 

True, I also thought about another thing, my wheels are staggered so I'd have to carry two extra tires in my trunk... luckily my advisor was able to get me a new tire with the warranty I have.

 

Point being machines are necessary. Tires don’t just fly on or off rims in 2021.

Those articles somehow support your argument FOR run flats? The only ‘expert’ quoted that mentioned safety was a BMW engineer in a decade old article, immediately followed by mention of a successful class action against BMW for run flats, and the complete BS assertion by him that using non run flats on a car designed for run flats is dangerous.

There is a lot of information for consumers on the tirerack.com (largest tire retailer by far) website. Show me where they sell RFTs as a way to prevent tires from flying off wheels in a blowout. Since RFTs are more expensive, it should benefit them to do so, no?
You know this how exactly? How did the rear tire stay on my fully loaded X5 after running over debris at 80? Or the front tire on my 5-series at 70 in the rain and after I crossed four lanes of busy 5 freeway to the right shoulder from the fast lane? Both miracles, maybe?

Not necessarily. RFTs likely do not cost manufacturers much more, if anything. Consumers are charged more because they are forced to replace RFTs with RFTs. How about you show me where it’s less expensive to add a dozen parts to a manufacturing process?
The operative word that you missed was modern. Your comments about tires flying off rims, loss of control following blowouts, and hand mounting tires sound like experiences from the 1960s. Modern German cars generally have (1) low enough profile tires that their stiff sidewalls, while certainly not designed for driving while deflated, do provide some rim protection and are far more difficult to get on and off wheels than an 80-series tire from the 60s, and (2) have sophisticated stability control systems that prevent loss of control in almost all circumstances.
To each his own, but I cannot continue a conversation if that’s your logic.

 

I replaced my Pirelli Cinturato P7 245/45-R18 Run Flat tires with similar Pirelli Cinturato P7 245/45-R18 non-RF tires.
The ride improved noticeably due to a reduction of 20 pounds of unsprung weight.
The RF's weigh 29 pounds each. The non-RF's weigh 24 pounds each.
The RF's contain 20.8% more material than the non-RF's.
The RF's cost 18.6% more than non-RF's using Tire Rack prices.
The RF's improve fuel economy by reducing total vehicle weight by not including a spare tire, jack and lug wrench.
The RF's increase the chance of being stranded due to a flat because most tire stores do not stock RF tires.
MB dealers are concentrated in metro areas so being within 50 miles of a dealer when a flat occurs is chancy.
One can purchase a spare and tools for little more than the cost difference between RF's and non-RF's.

BTW - RF's require special tire/wheel mounting equipment that many repair shops do not have.

 

I am so far from an expert that I don't think I can be further away. I am also not very educated on the topic. However, I can speak to my own experience and what I've been told by people who are experts, and who I know and respect. First, RF's are not designed to "hold up" and allow you drive home when there is a major, catastrophic tire failure -- like a major blow-out of the entire sidewall or something of the like. They are designed for you to be able to drive home if you run over a nail, or something that punctures the tread, tire, etc. I've had RF tires on SUV's and cars ranging from $35,000 to $100,000 and they have worked exceptionally well. I've gone over a nail, lost no tire pressure, and wouldn't have even known had it not been for a physical/visual inspection during an oil change or tire rotation.

Second, I don't know what's heavier, what drives better, etc. -- but RF's certainly offer a safety/comfort measure for normal situations that cause a flat tire, slow, gradual loss of tire pressure, etc. Third, having a spare -- even a donut -- is a good idea. And, lastly, over and above MB Roadside Assistance or whatever you call it -- Triple A is a great investment. They will come and change a tire, tow the car, or whatever you need. Just my experience, take what you like and leave the rest. All the best everyone!

 

What spare did you order? MB dealer says there is not part number because it never had one to start with. Also if you did get one did you test fit it on the front and back?