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My change of heart on run-flat tires vs. regular tires

Old 12-26-2012, 06:18 AM
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X25
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Default My change of heart on run-flat tires vs. regular tires

Until very recently, I was recommending Michelin Pilot Super Sports for those asking for a tire recommendation for a Corvette (or any other sports car for that matter), which are relatively cheap for Michelin tires, yet provide as good traction as the best street tires available.

Watching a recent episode of show "Fifth gear" drastically changed my mind, though. In this episode, a GT-R tries to break the record of highest average speed in an hour (which is at about 143 MPH right now). 18 minutes into this 1 hour drive on an oval track at 150 MPH, the right front tire disintegrated with a big bang! Having a flat at 150 MPH is no joke. Having a tire give up with a big bang is even scarier.

What happened then is the surprising part: NOTHING! The driver simply pulled over since the runflat tires that come with that car kept the car on track and the rest of the flat tire intact even though the car was driving at a speed much higher than what run-flat tires are designed for when there is a flat tire.

Long story short, now I see the RFT technology as a valuable asset for my safety. If you look it up on Youtube, one of the major reasons for major accidents at the track days is tire failure, and RFTs definitely make me feel safer.

An example to what happens if a tire gives up when you're driving flat-out:


EDIT: Found the video of GT-R's tire failure at 150 MPH:

Last edited by X25; 12-29-2012 at 10:13 PM.
Old 12-26-2012, 07:04 AM
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B y r o n
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". . . even though the car was driving at a speed much higher than what run-flat tires are designed for when there is a flat tire."


I have to disagree with this part of your statement, the tires are designed for the speed rating of the tire including the running at top speed without air.

Other than that I totally agree.
Old 12-26-2012, 07:05 AM
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Originally Posted by B y r o n
". . . even though the car was driving at a speed much higher than what run-flat tires are designed for when there is a flat tire."


I have to disagree with this part of your statement, the tires are designed for the speed rating of the tire including the running at top speed without air.

Other than that I totally agree.
As far as I know, you're not supposed to drive it at more than 55 MPH; is this not the case anymore?
Old 12-26-2012, 07:13 AM
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Originally Posted by Ozer
As far as I know, you're not supposed to drive it at more than 55 MPH; is this not the case anymore?
Once you get the loss or air or flat you're right, 55 MPH is supposed to be the maximum speed. However, when the tire is designed it has to be able to handle the loss of air/flat at any speed the tire is rated for.
Old 12-26-2012, 07:17 AM
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Regardless of the speed at which a RFT (EMT) lets go (which is an interesting data point nonetheless), I would consider keeping the speed down while I limped home/to service with a airless tire.

While the safety factor of a tire holding together at speed without air is compelling enough in and of itself, I feel that the biggest safety factor is the ability to not have to change a tire on the shoulder of a busy highway, a known risky act.

If I did not have run-flats, I would gladly destroy a wheel than to stop on the shoulder of a busy higway while idiots text, tailgate, drink and do drugs behind the wheel at high speeds, and have taught my family members to do the same.
Old 12-26-2012, 07:38 AM
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I came to that conclusion 12 yrs ago with my 2nd vette, a 02 coupe with GYRF's. RF's are a safety factor not unlike seat belts, IMO.
Old 12-26-2012, 07:59 AM
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So, it IS possible to learn something from television.... j/k. That's a good viewing to share with some.
Old 12-26-2012, 08:40 AM
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Ozer, you make a very valid point, I never thought of RFT beyond a convenience when having a flat, I will stay with RF's for sure, it's worth the expense and little bit bumpier ride, IMO, thanks for your post!
Old 12-26-2012, 10:01 AM
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Good point, however, the counterpoint would be that most RFT tires have far less track capability so anything other than straight line driving and you are actually less safe. The example of oval track is as close to normal DD driving (other than the speed) as possible. Move to a road course, however, and keeping the RFTs over, say NT05s, is NOT making you safer. The RFTs will do you no good braking from 130mph or when hitting a hairpin at 60mph (after braking).
I'm not totally knocking RFTs. I've taken advantage of driving to the tire shop with zero pressure myself. I just think you need to be more specific when claiming one tire is "safer" than another.
Old 12-26-2012, 11:40 AM
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Originally Posted by jbondfl
Good point, however, the counterpoint would be that most RFT tires have far less track capability so anything other than straight line driving and you are actually less safe. The example of oval track is as close to normal DD driving (other than the speed) as possible. Move to a road course, however, and keeping the RFTs over, say NT05s, is NOT making you safer. The RFTs will do you no good braking from 130mph or when hitting a hairpin at 60mph (after braking).
I'm not totally knocking RFTs. I've taken advantage of driving to the tire shop with zero pressure myself. I just think you need to be more specific when claiming one tire is "safer" than another.
I'm not so sure that logic holds-up. If I have a high-speed blowout on a curve (be it on the street or the track) the EMT would be the 'safer' choice to maintain control of the vehicle. In many respects street driving versus track driving is apples and oranges but sure, provided it doesn't rain I can run faster lap times on my Hoosier R100 or Michelin racing slicks versus running on EMT's. Notwithstanding there are speed limits to govern safety on the street, either type tire can only be safely driven to the limit of its capabilities. It's been years but I have braked from 130 mph to make a 60 mph curve on runflat tires. On 'track' tires I might have made that curve at 80 mph but that's neither here nor there....I was then on runflats and 60 mph was the limit I could safely make the curve. I'm not confusing being able to run faster with being able to run safer.

I would recommend to any novice road course driver to start with your normal street tires....even runflats. I maintain it will make you 'safer' (not necessarily faster) to first learn on your EMT's for a good long while. Learning to drive at speed with any type tire is not something you do in a day or a weekend....it takes regular practice. I'm convinced, for track driving it really helps to first learn, to get a 'feel' for your car (how it handles and what the limits are) on less sticky tires before graduating to stickier tires. It will make you a safer, better driver in the long run.
Old 12-26-2012, 11:59 AM
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We are taking about a very rare occurrence, regarding a blowout, on conventional tires. Especially on the street with lower tire temps.

Like I have stated before I have never had one in over 48 years of driving and another 35 years behind the wheel of an 18 wheeler.

Scare tactics for the glass half full thinking mentality.

But I will agree that each of us should be comfortable with our tire choice.
Old 12-26-2012, 12:09 PM
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yeah... but the ROLL CAGE saved that guy's life. "Oh F***!"




In either case - good point and thanks for sharing.
Old 12-26-2012, 12:32 PM
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I think my logic holds up just fine.
First, remember I acknowledged that, on the street, RFTs could arguably be safer.
Second, "IF" you have a blowout and "IF" it happens on a curve, significantly reduce the odds of RFTs being beneficial. Add to that the fact that, sidewall or no sidewall, a blowout in a curve is likely to upset the car enough that you would spin/crash regardless of having RFTs.
When you go out on a track your intention is to get as much out of the car as you are capable. Since RFTs typically will have less performance capability you are more likely to be on the bleeding edge of those than you will be on other, performance rated, tires, especially as you gain experience. Keeping in mind that you are going to the edge (or as close as you are willing to go) many, many times (about 100 times per session at Sebring) it is JMHO that cornering performance is far more important than blowout protection, ON THE TRACK.

Originally Posted by Wayne O
I'm not so sure that logic holds-up. If I have a high-speed blowout on a curve (be it on the street or the track) the EMT would be the 'safer' choice to maintain control of the vehicle. In many respects street driving versus track driving is apples and oranges but sure, provided it doesn't rain I can run faster lap times on my Hoosier R100 or Michelin racing slicks versus running on EMT's. Notwithstanding there are speed limits to govern safety on the street, either type tire can only be safely driven to the limit of its capabilities. It's been years but I have braked from 130 mph to make a 60 mph curve on runflat tires. On 'track' tires I might have made that curve at 80 mph but that's neither here nor there....I was then on runflats and 60 mph was the limit I could safely make the curve. I'm not confusing being able to run faster with being able to run safer.

I would recommend to any novice road course driver to start with your normal street tires....even runflats. I maintain it will make you 'safer' (not necessarily faster) to first learn on your EMT's for a good long while. Learning to drive at speed with any type tire is not something you do in a day or a weekend....it takes regular practice. I'm convinced, for track driving it really helps to first learn, to get a 'feel' for your car (how it handles and what the limits are) on less sticky tires before graduating to stickier tires. It will make you a safer, better driver in the long run.
Old 12-26-2012, 12:48 PM
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Originally Posted by Boomer111
Scare tactics for the glass half full thinking mentality.
Not sure I agree with such a blanket statement. As a pilot and aircraft accident investigator, I live and thrive in a world of safety and safety culture. If you can minimize risk, you do so. Has nothing to do with the glass being half full or half empty, or scare tactics for that fact. Flying is not inherently dangerous, but it is unforgiving.

I think performance cars fall into a similar category. Unless your absolute goal is performance only, such as in a race environment; if you can muinimize or eliminate risk through redundancy, fail safe design, technology, etc.; you should do so. Having seen the results of "different" thinking in the thousands of aircraft accidents I have investigated over 30+ years, it is quite sad when either innocent people are injured or killed; and/or the pilot is killed when technology could have saved his/her life.

JMO.

Old 12-26-2012, 01:00 PM
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Originally Posted by Aviator
Not sure I agree with such a blanket statement. As a pilot and aircraft accident investigator, I live and thrive in a world of safety and safety culture. If you can minimize risk, you do so. Has nothing to do with the glass being half full or half empty, or scare tactics for that fact. Flying is not inherently dangerous, but it is unforgiving.

I think performance cars fall into a similar category. Unless your absolute goal is performance only, such as in a race environment; if you can muinimize or eliminate risk through redundancy, fail safe design, technology, etc.; you should do so. Having seen the results of "different" thinking in the thousands of aircraft accidents I have investigated over 30+ years, it is quite sad when either innocent people are injured or killed; and/or the pilot is killed when technology could have saved his/her life.


JMO.

100% right to the point!
Old 12-26-2012, 01:17 PM
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Originally Posted by Random84
yeah... but the ROLL CAGE saved that guy's life. "Oh F***!"

I often wondered how many times "OH f***!"were found in those black boxes they recover after a crash.
Old 12-26-2012, 01:30 PM
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Originally Posted by Aviator
Not sure I agree with such a blanket statement. As a pilot and aircraft accident investigator, I live and thrive in a world of safety and safety culture. If you can minimize risk, you do so. Has nothing to do with the glass being half full or half empty, or scare tactics for that fact. Flying is not inherently dangerous, but it is unforgiving.

I think performance cars fall into a similar category. Unless your absolute goal is performance only, such as in a race environment; if you can muinimize or eliminate risk through redundancy, fail safe design, technology, etc.; you should do so. Having seen the results of "different" thinking in the thousands of aircraft accidents I have investigated over 30+ years, it is quite sad when either innocent people are injured or killed; and/or the pilot is killed when technology could have saved his/her life.

JMO.

I see what you are saying and I think I might add, "...when existing technololgy, if it had been used, could have saved his/her life." I do believe that is what you were implying.

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To My change of heart on run-flat tires vs. regular tires

Old 12-26-2012, 01:55 PM
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I think you need to know yours limits with the available equipment . An accident is rarely one cause , as you know its a chain of minor issues that cascade into a huge problem .
Knowing we drive low plastic bodied cars with thin ply tires . Judgement to know when things look bad sadly comes too late for some .

We live on trust based machinery . Thousands run tires at high speed without issue
One blow out we all stop / question why / what brand / speed / use . I rarely get over three digits in my driving .. non - RF tires will be fine .
Old 12-26-2012, 02:06 PM
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Originally Posted by Aviator
Not sure I agree with such a blanket statement. As a pilot and aircraft accident investigator, I live and thrive in a world of safety and safety culture. If you can minimize risk, you do so. Has nothing to do with the glass being half full or half empty, or scare tactics for that fact. Flying is not inherently dangerous, but it is unforgiving.

I think performance cars fall into a similar category. Unless your absolute goal is performance only, such as in a race environment; if you can muinimize or eliminate risk through redundancy, fail safe design, technology, etc.; you should do so. Having seen the results of "different" thinking in the thousands of aircraft accidents I have investigated over 30+ years, it is quite sad when either innocent people are injured or killed; and/or the pilot is killed when technology could have saved his/her life.

JMO.


I can agree with safety should always be a top priory. And have come from a commercial driving background I have had this implanted in my perspective with concerns of everyday actions.

My "half full" statment was more of a jab than any thing serious.

But we are talking years of tire improvements ahead of the time that the term "tire blow out" was more commonly applied.

For my driving style and the speeds attained on the street I consider it a non issue regarding any safety factor between the two tire options. And I can enjoy a better ride with less noise and improved handling for less money.

I think the real idea with the RF is to get the car home or to a garage for repairs with better convience, since the cars has no room for a spare or the need for extra weight.

Remember that the small low speed spare tire was a first option offered for space and weight savings.

Concerning air flight and safety I try not to fly when ever possible and will forgo vacations because of this. Being 35,000 feet in the air by my way of thinking just at times seems silly. I will fly but it takes a Ativan to get me in the plane.

Planes falling out of the sky is about as serious as it gets vs being on the side of the road waiting for a flat bed or fixing the tire. The bow out thing pretty much is a non issue nowadays. Compare this with air flight and crash survival rate and I take the tire blow out.
Old 12-26-2012, 02:23 PM
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I had my first blow out ( Right Rear) in my Z06 with the stock Goodyear Supercar tires on my way home from Carlisle this past summer. I hit a metal object while accelerating on an on ramp. DIC read 0 PSI and the warning came on to reduce speed. I was able to drive home at 65-70 mph for over 50 miles. The car was remarkably stable. I replaced both rears with the stock Goodyear runflats. I like them. I like the way they handle and they certainly proved themselves with that blow out.

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