I saw a video demo many years ago where somebody used a 2" hole saw to cut a hole in the sidewall of a GY run flat tire mounted on a Corvette. The car then went for a 50-mile ride.

I suspect that might have something to do with both the harsh ride and shorter life expectancy.

Run flats...

 

I had corvettes over several years with run flats. They were noisy as the tread wore down, not so sure about the harsh ride, tire wear seemed average-but after hitting a piece of someones muffler at speed- blowing out a front tire, I became a run flat fan-stayed in control and could limp home (talk about tire noise!) Also had a couple nails-was able to get to the tire dealer for replacement/repair with minimal hassle-I'd get them as replacements if available.

 

I don't know that I am comfortable saying runflats wear faster than non-runflats as a general answer. What I CAN say with 100% confidence is that most BMW, Mini, Lexus SC430, and Corvette owners I speak with directly will replace runflats witn non-runflats when they can. The ride is very hard with them and there isn't much "give" to them. That, combined with the fact they are about 50% higher in cost meant that most will buy a flat tire repair kit and take their chances.

Porsche does not use them because they do not corner to their satisfaction, and presumably degrade the performance ability of the car.

 

'Nuff said.

 

seems like an even splitg between factory tires and run flats-advantages and conveniences to both no doubt..

 

I'm the wrong breed of engineer to know for sure, but a moderately-informed speculation would be increased tread squirm from the reduced compliance of the tire body.

Personally, I wouldn't put anything but an N-rated tire on a Porsche, but even if I had enough motivation to de-rate the car so I could use a tire not designed for it, I'd not choose a run flat. We ran over a screw in the latest rain storm and did indeed get the dreaded "Flat tire!" light. No big deal since the puncture was in the tread, not a torn sidewall, though I didn't know it at the time. Driving moderately, I pulled into a safe parking lot, in a spot somewhat protected from the damnably cold wind, and hauled out the groceries filling the frunk so I could find the repair bits.

In my opinion, using the foam would render the tire useless and compel replacement, so I tried the pump alone first. Worked fine. At least on the dot twos, the pump seemed quite powerful enough. Put in ten pounds as quick as you could wish to bring the tire up to three bar. Then I monitored the pressure for the ten miles to reach home. Next day, I pumped the tire up again with our own compressor, which took about as long to my surprise. Took the car to a local America Tires that has done good work on our NSX in the past. They fix flats at no charge, but I offered a twenty-dollar tip and requested their best shop guy and the foreman's attention, given the problems that can be caused by such large wheels. They were quite good.

All pretty much of a muchness with using a spare in my experience. But when you cannot recover with the pump alone, or even with the foam, I haven't found our flatbed tows in this area to be terribly traumatic. You supervise the loading, hop in the truck and ride with the car to a suitable repair site. We live in the high desert of California so remote is a fair description of many drives we take, but the only serious concern is being out of cellphone coverage. Then you have to ask someone to call for you when they reach a covered area. Since we have people -- like America Tires -- who handle such tires as the Porsche needs within reasonable distance I can't see the nuisance of a spare is balanced by the off chance I'll cut a sidewall next time.

No run flats for us.

Gary

 

Thanks for the explanation. That makes sense why they wear faster.

I am not worried about nails. Half the time, I run over some debris and cuts the tire though. That's when a tow truck or spare would be really handy.

These days, I rent a car if driving long distance. This way, you don't have to worry about roadside assistance or mechanical failure while being far from home.

 

You can add Lexus GS owners to your list, Damon. You should see all the threads on ClubLexus about RFs and how HORRIBLE they are. Fortunately, my wife's GS came w/ a donut spare (even w/ the RFs) so as soon as the OEMs were 1/2 gone, I swapped into Conti Extremes w/o another thought. Some get the dealer to swap out RFs when buying. However, it was my first experience w/ RFs and I honestly didn't think they'd be "that" bad. But they were... Hell, even my wife noticed when I replaced them and that's saying something.

 

had RFs on my BMW
nightmare.. it barely ever worked.. hardly got me anywhere..
I would get more flats in my RF.. eventually I got fed up and got normal tires and never got a flat since.. much more comfy ride and less noise

 

Had RFTS on both my BMWs. Just terrible. Harsh ride and ridiculous tire wear. I would never use them again.

 

What about self sealing tires? Anyone know if they available in N tires to meet specs for Porshces? My nephew has a new Passat CC that has a spare and self sealing tires. To me, this sounds like the best solution. Any tire is trashed if the sidewall is damaged but I would consider self sealing tires for my Porsche if available.

 

Stay away from RFs. Heavy, expensive, and unpredicatable at the limit.

 

Wife had two SC430's over a 7 year period with run flats. We tried everybodys brand. Lucky to get much past 18000 miles and harsh ride. Really bad at road transitions, markers, etc. As they wore the noise and ride both got worse. Also had one go flat and had to drive it for about 10 miles. It was very unstable and wobbly (Word?). They seem like a great idea, but need lots of improvement IMHO.

 

The stock Dunlop RF's that came on our '06 Mini Cooper S lasted only 23,000 miles. I replaced them with Continental ContiPro RF's which were a great improvement, but still behave like most run-flats. I stuck with RF's because this is the wife's car and I did not want to have her get stranded with a flat. I would love to see how the Cooper S would handle on some good, non-RF skins.

Sounds like RF's on a Porsche are not a good plan. I hope to find out myself some day. Still dreaming about that Turbo S.

 

wow!!
you guys got great mileage!!
the longest mine lasted was around 5,000mile.. and then they would run flat... :/

the littlest pothole would cause them to burst