run-flat tires -- good, bad or ugly idea?

Yes you are right on track.

We owned a 2004 Sienna for many years and was a member of the Sienna Forum. The Sienna AWD had no spot for the spare, so it came with run flat tires. The AWD owners continually complained about the ride on run flats and relayed stories of tires failing and having to buy a replacement since the tires are unrepairable - if and when they were lucky enough to find a spare that would match the other tires.

One of the most viewed and popular threads was what type of normal tire were owners replacing their run flats with.

Here is an older article on these tires

Deflating Reality of Run-Flat Tires - Consumer Reports

More recent article
Run Flat Tires Vs Regular Tires: Everything You Need To Know » Tire Forge

We had friends who had a 2004 Sienna AWD with run flats and difference in ride quality between their vehicle and ours which was a 2004 Sienna FWD with regular tires was remarkable. Run flats have stiffer sidewalls so that you can continue to drive on them at a greatly reduced speed when they fail and if you do the sidewall and tire becomes compromised and must be replaced.

 

Ugly, as was replied above. In addition, run-flat tires have a high rolling resistance and therefore will yield poor MPG.

JeffD

 

beautiful idea, poor execution

 

Pends on where you want to wind up 'eh?
As Angel Eyes brilliantly pointed out in the movie: "People with ropes around their necks don't always hang."
However
(COMMA!!!)
I would like to point out that most people who hang DO have ropes around their neck.

Me?
I personally would not drive a car with 'run flats', but I wouldn't drive a HMMWV without them....and yes.
I know.
The Humvee is being replaced with the Joint Light Tactical Vehicle, because the F35 and the LCS programmes (conclusively!) proves that P.T. Barnum was RIGHT!

So.....there's a risk reward matrix to consider, and it's pretty obvious that your CFO is adding data points of her own to that formula.
Subie drivers tend to be fairly smart, and thus Subies more than likely all have spares, albeit sometimes the wee little doughnut kind.
BUT(!!!!)
Flats DO have to be changed.
The human animal is sexually dimorphic, and the half that are put in charge of procreation tend to be the smart half, or as they say in the military they tend more often to think about bad situations 'left of bang.'


Happy Spouse.
Happy House.
Absenting contrary data, I believe IMHO you should stick the crowbar into your wallet and buy her the bloomin tires that she thinks she wants, or at least come up with a slightly better line than "You're not worth the extra fuel" or "They're expensive!"
Both essentially the same sentiment.
It might be more expensive, but there's a nearly zero-percent chance that you'll take friendly fire if 'mistakes are made.'
Additionally, if the ride is sub-par (for a Subie driver in the PNW? ) then you can dismount them, plug in a more conventional substitute, and sell the nearly-new RFTs for cash, and you can NEVER have too much off-budget CASH, my friend!!!

I bought my last handgun with off-the-books cash!


https://www.bridgestonetire.com/learn/tire-technology/run-flat-tires/

 

Yep, we owned a 2005 Sienna AWD with the infamous run-flat tire that didn't run when it was flat, and treads were worn out prematurely in most cases in less than 20K. The cost of replacement was over $1200 back then and not all tire shops had special equipment to deal with FRT, so it was very difficult to get one installed locally. The case ended up in a class action lawsuit. As a part of the settlement, Toyota agreed to replace a set of run-flat tires if they were prematurely worn... but with the same "defective" run-flat tires. We ended up with two sets of them in 40K miles. At the end of the second set (free replacement of the original set), I replaced them with conventional tires which lasted the rest of the car's life or ~60K miles.
Toyota Sienna Run-Flat Tire Class Action

Those points are all true for the earlier run-flat tires the ones I had on the 2005 Sienna. But I have read that newer generations of RFT have improved on its ride comfort and some repairability. Still, they are more expensive than most premium tires of the same size. I have never purchased RFT after my experience with Sienna, so can't comment on the other qualities of the tires.

 

Friend got a Sienna AWD a couple years before the new hybrid version. They didn't stay with run flats for replacements.

 

My X3 came with run-flats as standard. I think all BMWs do.

They're fine in the city. But when I'm out in the sticks, it can be impossible to replace them. Fitters in small towns don't have them in stock, and some of them can't even fit the tyres when they do get hold of them, because they require much more force to get them onto the rims than normal tyres do.

The other issues are weight, ride and handling. BMWs are designed for run-flats, and feel a bit weird with normal tyres - kind of floaty and unsettled. I suspect that car designed for normal tyres may feel wrong with big, heavy run-flats.

 

Runflats can be repaired, with the same rules and techniques as non-runflat tires.
Your mechanics gave all good other reasons.
Comfort vs security may be a decision tree.
With all-wheel drive, replacing costs could also be a concern, at the very least you may have to replace two, but that would be the same as non-runflats too.
Not mentioned was performance, runflats are not the best for autocross, LOL, if sportiness matters to your wifey.
Good luck with your decision.