Rennteam 2.0 - EN - Forum - Re: Run Flat Tires? - Page2

Dec 31, 2005 1:36:48 AM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005

Run Flat Tires?

With no spare in the 997s, the idea of run flat tires makes real sense. I think I've seen them poo-pooed here BUT I watched an episode (today) of 5th Gear I'd recorded several weeks ago where they ran a BMW (sorry, didn't catch which one) around a track then drilled holes in each tires sidewall and ran the track again. The lead fellow (who snickers more the faster he drives and always appears to be having a fine old time at his job) ran the track at speeds up to 100 m.p.h. and remarked how well the Bimmer handled even with FOUR flat tires. He remarked it wasn't only surprising how well the car handled BUT that he was amazed that the tires were still on the rims!
He said the tires recommended they be driven a max of 50 miles at a max of 50 m.p.h.
Anyone feel like commenting or recommending any run flat tires for the 997 P-car?
I'll go Google it too.
Found this URL.
http://autos.msn.com/advice/article.aspx?contentid=4021164
Oh, looked for the URL for this episode of 5th Gear but couldn't find it.

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Dec 31, 2005 3:03:13 AM

bstew: Expert; Loc: NC, USA; Posts: 1797, Gallery; Registered on: Oct 11, 2005; Reply to: Dasein

Re: Run Flat Tires?

I think run flat would be great on the 997. My eyes are on this topic.

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Dec 31, 2005 3:10:55 AM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: bstew

Re: Run Flat Tires?

I heard they are heavy and would mess up our car's everyday performance in a way that would be noticeable to anyone.

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Dec 31, 2005 3:26:10 AM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: bstew

Re: Run Flat Tires?

I think they may be standard equipment on future Porsches. I mean, think about it, if you're Porsche and you take away the spare tire, aren't you sort of morally obligated to put damn run-flat tires on the car instead of providing a big BAND-AID?? Miata took away the spare and provides the same solution as the Porsche, a can of goo!
Cheap. I mean, really, give us a break here!

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Dec 31, 2005 3:33:23 AM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: Dasein

Re: Run Flat Tires?

MMD, not everything we hear is correct.
Besides, things change.
If Audi and Mercedes (and others) can remove the spare and put run-flats on their cars I think Porsche could lose a few dollars and do the same.
It would be real nice to get home or to a dealer.
Anyway, how about offering a choice of run-flats?
That wouldn't confuse the anal-retentive Teutonic mind too much would it? (I'm German so no flames please.)

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Dec 31, 2005 3:35:38 AM

JMShrink: Pilot; Loc: California; Posts: 395, Gallery; Registered on: Oct 12, 2005; Reply to: Dasein

Re: Run Flat Tires?

Doesn't Porsche provide some roadside assistance? I know that they won't change it on the field for you, but don't they provide a tow?

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Dec 31, 2005 3:37:28 AM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: JMShrink

Re: Run Flat Tires?

Yes they do and I hear they come REAL FAST!
As in HOURS!

PLus, I do most of my driving in mountains where even cell phones don't work.

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Dec 31, 2005 3:46:08 AM

JMShrink: Pilot; Loc: California; Posts: 395, Gallery; Registered on: Oct 12, 2005; Reply to: Dasein

Re: Run Flat Tires?

Quote:
Poseur (dweiser) said:
Yes they do and I hear they come REAL FAST!
As in HOURS!

PLus, I do most of my driving in mountains where even cell phones don't work.

I bet those run flats are sounding pretty good right now!
I don't have any mountains to worry about, just have to worry about going to downtown Detroit. Won't be driving my 997 C2 down there anyways when it arrives this spring.

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Dec 31, 2005 3:51:51 AM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: Dasein

Re: Run Flat Tires?

Quote:
Poseur (dweiser) said:
MMD, not everything we hear is correct.
Besides, things change.

Problem is they're heavier. That means the car's heavier, the unsprung weight is heavier, rolling mass is greater so getting them to roll takes more HP, getting them to stop rolling takes more brakes. So they do significantly effect performance assuming they're heavier.

I hope you're right though; maybe the situation changed so they're extremely lightweight.

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Dec 31, 2005 6:39:50 AM

Grant: Rennteam VIP; Loc: Denver, CO , United States; Posts: 12586, Gallery; Registered on: Aug 21, 2002; Reply to: MMD

Re: Run Flat Tires?

They have very poor ride comfort as well as performance. Worse in every way than a good "regular" tire (unless it has no air...).

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Dec 31, 2005 8:21:19 AM

stork: Junior; Loc: OH and NC; Posts: 145, Gallery; Registered on: Dec 3, 2005; Reply to: Dasein

Re: Run Flat Tires?

BMW using run flats? Yes, but it is sorta normal BMW family cars. BMW 330 is a good car and it has run flats available. M3 and M5 NO RUN FLATS! Mercedes SL 500 has runflats only in 17 tires. Not available in 18 or 19s. Thus, in real high performance situations, no run flats are available. Is that because tire manufactures assume we do not want them or do they know the run flat performance for these situations is lacking? I suspect with the stiffer and heavier side walls, run flats do not offer ultra high performance in the tire profiles we need. I have a 2004 M3 and 19s are the only listed tires. I put 18s on for winter , but did not find run flats to this. For my 19s in summer, BMW gives me fix-a-flat and no spare. The sales people talked about run flats, but when I said are you sure you can say run flats when we are talking about the M3? Oh yeah, they then realized, BMW does not put run flats on the standard 19 rims of the M3. Performance issues is why they said there are no run flats on the M3. Ferrari does not have any run flat options in the 360 or 430. So on the 997 and 997S (C2 and C4) there does not seem to be any run flat options made by any tire company. Since other car corporations do not place runflats on there high performance car versions either, I bet it is simply that run flats can not perform in these situations.

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Dec 31, 2005 10:09:58 AM

dhayek: Rennteam Master; Loc: Beirut , Lebanon; Posts: 3839, Gallery; Registered on: Jul 7, 2004; Reply to: stork

Re: Run Flat Tires?

Quote:
stork said:
BMW using run flats? Yes, but it is sorta normal BMW family cars. BMW 330 is a good car and it has run flats available. M3 and M5 NO RUN FLATS! Mercedes SL 500 has runflats only in 17 tires. Not available in 18 or 19s. Thus, in real high performance situations, no run flats are available. Is that because tire manufactures assume we do not want them or do they know the run flat performance for these situations is lacking? I suspect with the stiffer and heavier side walls, run flats do not offer ultra high performance in the tire profiles we need. I have a 2004 M3 and 19s are the only listed tires. I put 18s on for winter , but did not find run flats to this. For my 19s in summer, BMW gives me fix-a-flat and no spare. The sales people talked about run flats, but when I said are you sure you can say run flats when we are talking about the M3? Oh yeah, they then realized, BMW does not put run flats on the standard 19 rims of the M3. Performance issues is why they said there are no run flats on the M3. Ferrari does not have any run flat options in the 360 or 430. So on the 997 and 997S (C2 and C4) there does not seem to be any run flat options made by any tire company. Since other car corporations do not place runflats on there high performance car versions either, I bet it is simply that run flats can not perform in these situations.

the ferrari f430 offers the option of run flat tyres ,or the option to buy a mini spare wheel. msrp of run flats are around 1500$

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Dec 31, 2005 10:28:20 AM

Carlos from Spain: Rennteam Moderator; Loc: Spain. , Spain; Posts: 21152, Gallery; Registered on: Feb 9, 2003; Reply to: MMD

Re: Run Flat Tires?

Quote:
MMD said:
Problem is they're heavier. That means the car's heavier, the unsprung weight is heavier, rolling mass is greater so getting them to roll takes more HP, getting them to stop rolling takes more brakes. So they do significantly effect performance assuming they're heavier. I hope you're right though; maybe the situation changed so they're extremely lightweight.

No, its not changed, they are heavier and like grant says, also stiffer, so they are not only worse performance wise but in ride quiality as well. They have been improved over the years but the physics still remains.

An important factor in run-flats is that since they are so different than normal tires (heavier and stiffer) the car in which they are going to be used must have its chasis/suspension designed for run-flat's characteristics to compensate. Thats what they did with the M5 for example. This was the most significant improvement in run-flat tires, that the cars come designed for them, whereas in the past they weren't and hence ride and performance was even worse.

So forget about it in the 997, it was not designed for them.

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Dec 31, 2005 11:20:16 AM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: Carlos from Spain

Re: Run Flat Tires?

Thanks all, especially stork for the info.
Maybe one day the technology will allow for a good handling run-flat. Until then, I'm going to feel like ET if something happens to one of my tires, "HOME, I just want to get HOME".

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Dec 31, 2005 1:15:11 PM

bstew: Expert; Loc: NC, USA; Posts: 1797, Gallery; Registered on: Oct 11, 2005; Reply to: Dasein

Re: Run Flat Tires?

I don't care if they are heaver, run flat tires would be a great choice. Sorry but I don't get in my 997 and burn down the road every change I get or race on the track. I'm sure Porsche could work with a tire company to make a great run flat tire just for the 911 if they want. Heck when my current tires wear out I will look into a set.

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Dec 31, 2005 2:59:13 PM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: bstew

Re: Run Flat Tires?

Roger from TireRack.com got back to me. Here's what he had to say:
"Thanks for your inquiry. Unfortunately, none of the tire companies we represent are currently offering Run-Flat tires for your O.E. application. I am not sure what Porsche has done for you in regards to a back up in case of a flat tire, however, Continental has recently introduced their new Conti Comfort Kit for situations like this - see details below ..... ".

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Dec 31, 2005 3:15:20 PM

TheOldMan: Co-Pilot; Loc: Montreal, Canada; Posts: 214, Gallery; Registered on: Sep 27, 2004; Reply to: Dasein

Re: Run Flat Tires?

I have driven a BMW 645 with run flats. Despite coments to the the contrary, I found the run flats to be very acceptable tires on a car of this type.

If the technology advanced to the point that they would work on a 911, I would buy a set. Even if I gave up a little bit of performance, they would make sense. My perfect drive is through the twisty roads of the mountains far away from traffic and the services of the city. In these areas, the closest Porsche dealer is 8 hours away. I think twice before going for these types of drives.

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Dec 31, 2005 3:28:21 PM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: TheOldMan

Re: Run Flat Tires?

Very similar to my types of drives and my concerns old hand to OldMan. A cell phone won't even work in the mountains where I live/drive so Porsche's "wonderful" roadside assistance isn't much help if one can't reach them.
I wonder who here could bring this request (run flat tires for the 997) to Porsche and to those tire companies that make tires for the 997?

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Dec 31, 2005 4:06:39 PM

stork: Junior; Loc: OH and NC; Posts: 145, Gallery; Registered on: Dec 3, 2005; Reply to: dhayek

Re: Run Flat Tires?

Yes, you are correct about Ferrari. I was using tire rack as my guide, but I googled Ferrari and run flat and Googyear came up under Eagle F1s and they have beening working on run flats in this ultra high performance tire. Only a few tire sizes now and not Porsche 997 size. Yes, I too would be interested in great run flats for a couple reasons. I use cars everyday, year round, and do not simple let them sit in the garage. I do not live in major urban area. I have all kinds of road side service option available, but I have often found NOBODY, even the dealers have the exact tire I need (ie right front from this or that tire company in stock) when I am on the road. I am a real world driver and love the idea of run flats assuming good performance. However, my wife had runflats on here Lexus 430SC (powerful engine but not geared or set up as sports car)and the average car was getting horrible tire wear in very pricey tires. She gave up and went with non run flats, fix-a-flat, and Lexus road service ( oh yeah, there is me...who I am sure is the first person she will call to come and help her....then the run flats may seem cheap to both of us!!!

)

anybody know of a tire company making or about to make run flats in 997 tires sizes????

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Dec 31, 2005 5:10:54 PM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: stork

Re: Run Flat Tires?

I just went to Goodyear.com and asked if they had any plans to produce a run flat tire for the 911. Since it's me asking I'm sure they'll have one out next week for us.
But seriously, if a few people email them asking about run flat tires for the 911 they'll be more apt to perhaps produce one.
Here's the URL to ask them, Stork (above) says it's the Eagle F1 ........
http://www.goodyear.com/email/faq.html
Thanks,
Don

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Dec 31, 2005 5:15:11 PM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: stork

Re: Run Flat Tires?

Just look at the weight issue. Rubber is heavy. Thicker sidewalls, AND I think there's a thick plastic ring in there surrounding the wheel circumference that the flat tread can ride on when the air is gone. Gotta be at least 10-15 lbs per wheel?

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Dec 31, 2005 5:16:28 PM

964C2: Expert; Loc: Dallas, TX , United States; Posts: 1825, Gallery; Registered on: May 11, 2004; Reply to: Dasein

Re: Run Flat Tires?

....doesn't GM use run-flats for the Corvette??

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Dec 31, 2005 5:47:51 PM

Dasein: Veteran; Loc: Mountains of western NC, USA , United States; Posts: 933, Gallery; Registered on: Sep 19, 2005; Reply to: Grant

Re: Run Flat Tires?

Gee MMD, no-one's making you purchase a run flat tire. However, there are those of us interested in exploring this option.
Yes 964C2, the Corvette has come with run flats for something like 10 years now. They (Corvette) don't provide a spare either but, unlike Stuttgart, they give their owners a way to at least get the vehicle back home or to a tire shop!

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Dec 31, 2005 6:05:30 PM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: Dasein

Re: Run Flat Tires?

Quote:
Poseur (dweiser) said:
Gee MMD, no-one's making you purchase a run flat tire. However, there are those of us interested in exploring this option.

Eaaaaasy big fella. We're all just trying to get the details, info, impressions, facts, opinions, speculations out on the table for hobby-related enjoyment.

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Dec 31, 2005 6:13:10 PM

throt: Rennteam VIP; Loc: London , United Kingdom; Posts: 6078, Gallery; Registered on: May 9, 2005; Reply to: MMD

Re: Run Flat Tires?

Quote:
MMD said:

Eaaaaasy big fella.

Lol , easy boys easy

throt..

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Dec 31, 2005 6:20:16 PM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: throt

Re: Run Flat Tires?

Quote:
throt said:
Quote:
MMD said:

Eaaaaasy big fella.

Lol , easy boys easy

throt..

LOL. Nahhhhh, everythings coooooool. HEY! I'd looooooove to purchase/install run flats! Not gonna do it if they're a PITA though.

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Dec 31, 2005 6:37:08 PM

964C2: Expert; Loc: Dallas, TX , United States; Posts: 1825, Gallery; Registered on: May 11, 2004; Reply to: MMD

Re: Run Flat Tires?

Quote:
MMD said:
Just look at the weight issue. Rubber is heavy. Thicker sidewalls, AND I think there's a thick plastic ring in there surrounding the wheel circumference that the flat tread can ride on when the air is gone. Gotta be at least 10-15 lbs per wheel?

I would be very surprised if the weight difference is more than 5 pounds. It's probably less than the difference in wheel weight between 18" and 19" wheels

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Jan 2, 2006 4:13:07 PM

Paul S in TX: Co-Pilot; Loc:; Posts: 259, Gallery; Registered on: Jun 20, 2002; Reply to: 964C2

Re: Run Flat Tires?

Quote:
964C2 said:
....doesn't GM use run-flats for the Corvette??

Yes--and according to Chevy's website, even on the Z06. That said, I know several Corvette owners who got rid of the EMT/run flat tires for conventional tires and a can of "goop" because of ride and handling issues.

Frankly, if there's any handling compromise I don't want EMT/run flats. The best solution would be Porsche admits it was a mistake, and puts the front trunk back to the way it was in the 996 and stick a spare and jack in there.

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Jan 2, 2006 5:00:13 PM

Jim48: Senior; Loc: Virginia, USA; Posts: 639, Gallery; Registered on: Oct 24, 2005; Reply to: Paul S in TX

Re: Run Flat Tires?

Quote:
Paul S in TX said:
Quote:
964C2 said:
....doesn't GM use run-flats for the Corvette??

Yes--and according to Chevy's website, even on the Z06. That said, I know several Corvette owners who got rid of the EMT/run flat tires for conventional tires and a can of "goop" because of ride and handling issues.

Frankly, if there's any handling compromise I don't want EMT/run flats. The best solution would be Porsche admits it was a mistake, and puts the front trunk back to the way it was in the 996 and stick a spare and jack in there.

Is it possible to run one of those small spare tires on a Porsche? Whether used on the front or rear, might have to keep the speed below 50 mph. That's still not bad if it gets you to where you can get a replacement tire.

Jim

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Jan 2, 2006 5:02:30 PM

MMD: Rennteam VIP; Loc: usa; Posts: 9652, Gallery; Registered on: Dec 16, 2004; Reply to: Paul S in TX

Re: Run Flat Tires?

Geez, Guys, get a DIY plug kit, and a spare. THAT should take care of all your problems. Run flats onto all four wheels?! Pardon me, but now that I'm sober (happy new year), it seems like that's only a good idea for Hummers in a war zone and Grandma's car?

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