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Discussion Starter · #1 · (Edited)
Reviving a familiar topic due tothe fact that the M5s have no spare tire-- just the micky mouse blow-me system.

In checking with The Tire Rack, I see that there's now at last 3 run-flat tires in the original sizes for the E39 M5s: Bridgestone Potenza RE050A, Goodyear Eagle F1 Supercar EMT, and Dunlop SP 01-DSST.

Anyone have any experience or information about using any of these tires on the E39 M5s?

What are the general disadvantages of run-flats? I hear that modern run-flats perform virtually as well as "regular" tires, and for those of us (like me) who are concerned about getting a flat while driving late at night somewhere in the boonies, it would be a fair trade off to sacrifice some performance for the added security.

Thanks for your input.

Wilkie
 

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Run flats generally are harder riding and do not offer as good handling and feel. I would avoid them unless they are on a newer car like the E90- there the suspension was calibrated for the run flats and supposedly they work quite well.
 

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Discussion Starter · #4 ·
Just read an article in the latest Road & Track, about run-flats. Claims that the latest run-flats (in particular, Pirellis) are as smooth, comfortable, quiet as non run-flats, with comparable performance. This was on a BMW 3 series test car. Hopefully, someone with first hand experience using run-flats on an M5 will give a report.
 

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Wilkie said:
Just read an article in the latest Road & Track, about run-flats. Claims that the latest run-flats (in particular, Pirellis) are as smooth, comfortable, quiet as non run-flats, with comparable performance. This was on a BMW 3 series test car. Hopefully, someone with first hand experience using run-flats on an M5 will give a report.
Have driven the M5 with runflats, dont remember brand. And also drove them with the Pilot Sports. IMHO the average driver wont be able to tell much, If any of a difference in their daily driving. At the limit of the tire it is more noticable.
All of our 6 series cars have run flats on them as well and they ride very nice and the car still handles good at the limit. Hope this helps.
 

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I have them on the 540i, they feel real strange when they blow.
The danger seems that the tyre still gets over heated when flat and can rip apart causing more damage.
I'd like to find a tyre pressure sensor upgrade kit.
 

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Dunno. I looked at the specs and run flats are looking like a better option for my next set. They are heavier than some regular tires but not all. The Eagle rears weigh 29 pounds but SO3 Bridgestones (regular tires!) are 31, so I actually could save 2 pounds per wheel by switching to the Goodyears. PS2s and Conti SportContact2s weigh only 25 pounds, however. I tend to use my M5 mainly for longer trips now, so this is why runflats are starting to make sense to me. But if you read the reviews on TireRack, everyone complains about the noise, vibration and poor grip of the runflats in our size except the Bridgestones (which weigh 34 pounds!).
 

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Discussion Starter · #8 ·
Sounds like run flats make sense for me, since they will be primarily for street use, and not for the track. I will seriously consider the Bridgestones for my next set, which should be coming up soon. That would solve my no-spare-tire concern on my long hauls.
 

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What would the costs difference be between run-flats and regular tires? Are they as duarable?

Mark
 

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Discussion Starter · #10 ·
MAH said:
What would the costs difference be between run-flats and regular tires? Are they as duarable?

Mark
Hi Mark,

Per the Tire Rack web site, the Bridgestone RE 050A Run Flats, front/rear, cost $278/$329, while the "regular" RE 050As are $218/$267. Also, the Dunlop SP Sport 9000 (non Run Flats) cost $225/$254. So, it appears that there is a small premium to pay for the run flats. Don't know about the wear, factor, though.

Also, I think I heard somewhere that once run-flats have been driven on while flat, the tire thereafter cannot be repaired, but must be replaced. Is this true?
 

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MEnthusiast said:
Run flats generally are harder riding and do not offer as good handling and feel. I would avoid them unless they are on a newer car like the E90- there the suspension was calibrated for the run flats and supposedly they work quite well.
I agree 100%
 

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My Brothers 2005 545i Sport has the DSST'S and it rides very hard. Very expensive to replace. He wants to put PS2's on when they wear out.
 

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Guys, on an earlier thread about runflats, there was debate about whether the M5 can use runflats safely because the tire pressure monitoring system on the M5 is not compatible with runflats (apparently it is different than the monitoring system on the Z8).

Any other (or new) thoughts/experience on this?
 

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I have the Dunlop runflats I use in the summer and then put on Winter Sport Perellis that I have on my stock wheels in winter. I had the tire moniter go off once with a heavy load and no flat or pressure change. Then I had a flat on a winter tire and the moniter did not go off but thankfully I only went a short distance before I stopped and saw the flat. I have Smart Tire on my Porsche summer tires and it works well. I cannot see a differance in ride or noise with the runflats and they are wearing well. I do not track the car. Will
 

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Wilkie said:
Hi Mark,

Per the Tire Rack web site, the Bridgestone RE 050A Run Flats, front/rear, cost $278/$329, while the "regular" RE 050As are $218/$267. Also, the Dunlop SP Sport 9000 (non Run Flats) cost $225/$254. So, it appears that there is a small premium to pay for the run flats. Don't know about the wear, factor, though.

Also, I think I heard somewhere that once run-flats have been driven on while flat, the tire thereafter cannot be repaired, but must be replaced. Is this true?
Yup, once they have been run flat for a while, they are done.

Last month I saw a Mini Cooper S come in my neighborhood tire shop and when they took the tire off, it was full will granular bits of rubber dust, large amounts of it, definitely a one-time use...
 

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Wilki, no I use the runflats on my Breytons, they look great and I have had no issues except the one time I had the moniter go off falsely. I was coming off the mountains fromTaho to Reno with a full load and stopped to check all tire pressures, no problems. It has never happened since. Will
 

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I had a Mini Cooper S with runflats and those were a little hard. What I have heard from Z8 owners is that they have abandoned runflats due to performance issues.
 

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Just to clarify the discussion...if you go to run-flat tires you must use another system to monitor tire inflation other than the existing M5 system.
Run-flat tires will not deviate enough in their rolling circumference with low or zero pressure to activate the warning system.
Failure to properly identify extremely low or zero pressure in run-flat tires puts you at more risk than using the current OEM tires and M5 system since it can lead to catastrophic tire failure, something that is normally rare these days.
Funny story on this subject, I noticed a co-worker had these installed on his 330 convertible only because I could hear he had a flat tire when he left from work the other day. He didn’t have a monitor system and did not know his tire was flat; don’t know how long this had existed. Luckily for him, he does not do much autobahn driving.
Ken
 

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Discussion Starter · #20 ·
kwalls said:
Just to clarify the discussion...if you go to run-flat tires you must use another system to monitor tire inflation other than the existing M5 system.
Run-flat tires will not deviate enough in their rolling circumference with low or zero pressure to activate the warning system.
Failure to properly identify extremely low or zero pressure in run-flat tires puts you at more risk than using the current OEM tires and M5 system since it can lead to catastrophic tire failure, something that is normally rare these days.
Funny story on this subject, I noticed a co-worker had these installed on his 330 convertible only because I could hear he had a flat tire when he left from work the other day. He didn’t have a monitor system and did not know his tire was flat; don’t know how long this had existed. Luckily for him, he does not do much autobahn driving.
Ken
This may seem like a stupid question, but since I've never used runflats, I have to ask. If a runflat tire loses its air, can't you tell simply by a close visual inspection?
 
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