stock tires *that* bad?

[Rafale]

Originally Posted by Jay Zone

The point is "how much do you value safety" we"ve got airbags and crushzones for collisions with trees and deer. Since I"m not on the track and i"ve seen the effects of a high speed blowout I value safety over a minor inconvenience.

Btw if you remove the five airbags in your Z you can shed weight. Probably not an option we want to consider.

JZ

I agree with you on the airbag. The fact is that they are much more useful! Collisions are much more likely than blow outs. The most likely reason why I would have a life threatening accident caused by a blow out would be .... a follow on collision. And the airbags do not make noise, do not add 8lbs-10lbs of unsprung weight by corner and do not change my driving feel. Bottom line is, RFTs sacrifice is way bigger than the itty bitty and arguable safety advantage they offer.

[Jay Zone]

Originally Posted by Rafale

I agree with you on the airbag. The fact is that they are much more useful! Collisions are much more likely than blow outs. The most likely reason why I would have a life threatening accident caused by a blow out would be .... a follow on collision. And the airbags do not make noise, do not add 8lbs-10lbs of unsprung weight by corner and do not change my driving feel. Bottom line is, RFTs sacrifice is way bigger than the itty bitty and arguable safety advantage they offer.

Much less likely but at speed????
Airbag didn't help this gentleman.

Peace
JZ

[Dr Stig 2]

I've bever had run flats before - was wary from their reputation, but buggered if I hear much road noise from them (and I have the same RE050 in a non RFT on my old Mazda 3 MPS), and the ride is great considering the type of car...
On grip - well the RE050 was never really able to cope with the 380NM torque in the MAzda so I give it no chance against the 450-500Nm in the Z4 - even with another 60mm of tread width.

I'm not saying there aren't better tyres out there, but I wll wear them out before I think of changing them.

[teagueAMX]

Originally Posted by Jay Zone

Much less likely but at speed????
Airbag didn't help this gentleman.

Peace
JZ

The interesting thing Jay, a RFT probably would not have prevented that accident. That isn't their primary purpose. Although RFT are intended to reduce the impact of a catastrophic blowout, their primary purpose to be driven flat, hence the name Run Flat Tire; not Blowout Preventing Tire. They prevent a driver from getting stuck in some remote place without a spare. He could drive the flat tire at low speeds to a service location. People have blowouts with RFT.

When you analyze that video, which I did in spite of the poor quality, you realize the car is your basic POS - not a BMW handled with TLC. Not taking that scene lightly which was terrible and I assume resulted in at least one fatality. But the point is you don't know what circumstances led to the disaster.

Here's just a few questions I would ask: What were the conditions of his tires, were they under inflated, over inflated, was there decent tread life on the tire, was there pre-existing damage to the tire sidewall, how fast was he going, did he exceed the speed rating of the tire and did it overheat, etc.? So pointing to a terrible accident and saying "Look what happened to a guy who didn't have RFT" is not accurate. For all we know he had a worn out set of RFT on that car.

[Jay Zone]

Originally Posted by teagueAMX

The interesting thing Jay, a RFT probably would not have prevented that accident. That isn't their primary purpose. Although RFT are intended to reduce the impact of a catastrophic blowout, their primary purpose to be driven flat, hence the name Run Flat Tire; not Blowout Preventing Tire. They prevent a driver from getting stuck in some remote place without a spare. He could drive the flat tire at low speeds to a service location. People have blowouts with RFT.

When you analyze that video, which I did in spite of the poor quality, you realize the car is your basic POS - not a BMW handled with TLC. Not taking that scene lightly which was terrible and I assume resulted in at least one fatality. But the point is you don't know what circumstances led to the disaster.

Here's just a few questions I would ask: What were the conditions of his tires, were they under inflated, over inflated, was there decent tread life on the tire, was there pre-existing damage to the tire sidewall, how fast was he going, did he exceed the speed rating of the tire and did it overheat, etc.? So pointing to a terrible accident and saying "Look what happened to a guy who didn't have RFT" is not accurate. For all we know he had a worn out set of RFT on that car.

I respectfully disagree. Runflats are less likely to suffer a blowout and if they do are far more likely to remain controllable. This has been demonstrated in numerous functional tests and demonstrations. for example:

Bridgestone 3G RFT's -- New generation run-flat tires addresses RFT complaints
The BMW enters the massive skidpad at more than 100 mph and begins a sweeping right turn along a soldiered row of orange cones. On cue, a pneumatic device attached to the hub of the spinning left rear wheel instantaneously rips its air valve clean out. Abruptly unsettled by the simulated tire "blow-out," and the collapse of the tire, the family wagon plunges into a long and flat uncontrolled spin knocking the hapless cones skyward in its wake. The BMW finally comes to a rest off course, facing 180-degrees from its original direction of travel.

Melodramatic in execution, the tire demonstration was repeated again moments later. This time the BMW was fitted with a set of Bridgestone's new third-generation run-flat tires. The high-speed blow-out again unsettled the car, but riding on sustained tire sidewalls it remained controllable as it tracked within the cordoned lane of orange cones and gently came to a stop.

The demonstration was powerful. Without a doubt, run-flat tires do work. Unfortunately, we've never met a set that didn't ride rough, feel like anchors, or cost us an arm and a leg at the register. We typically avoid them at all costs. Determined to make a change, Bridgestone invited us to Italy to try out its latest iteration of run-flats, promising to alter the way we think about the technology. What is this new tire? Why is it different from its predecessors? And, most importantly, how does it ride?


Full story can be found here: Reviewed: Bridgestone 3G RFT Tires take the shock out of run-flats.

TeagueAMX. True he was driving a POS, but a blowout is a blowout and POS or not if preventable or controllable the odds of survival go up Bimmer or not.


JZ

[teagueAMX]

I did not deny that RFT are intended to reduce the impact of a blow out, as noted in my statement that you quoted. But I also remember reading that press release when it was originally published. It was a tour put on for journalists, and in fact not a test conducted under controlled conditions.

As far as the Youtube video is concerned: Just because I said it was a POS, doesn't mean that accident would have been prevent by RFT. You didn't answer my questions from the video you presented:

• What were the conditions of his tires?
• Were they under inflated?
• Were they over inflated?
• Was there decent tread life on the tire?
• Was there pre-existing damage to the tire sidewall?
• How fast was he going?
• Did he exceed the speed rating of the tire and did it overheat?

Any of those same questions could be asked about a RFT blowout. And my last point was that you point to a terrible accident and say "Look what happened to a guy who didn't have RFT" but you don't know that his car wasn't equipped with RFT.

Are you suggesting that RFT guarantee no blow outs? Of course not! Sure, one can say there is a reduction, but how much? Is there a 1 percent reduction, 5 percent, 10 percent, 15 percent, 20 percent, 50 percent, 75 percent? Nobody can answer that question.

So it can be said that RFT may help prevent serious accident during a blow out, but nobody can say how much they reduce the risk because there are too many variables. Then it's no different than any other risk analysis: cost of prevention vs availability of resources vs practicality of implementation vs probability of danger vs frequency of risk. The bottom line in risk prevention, especially with driving a car, is a practical matter, not scientific.

To sum it up, although I appreciate your argument it's basically an emotional appeal. I have to ask: how much risk do you feel stepping out of your front door going to work, getting on a plane, having surgery, playing aggressive sports, or the big one: why do you drive a sports car?

I think we'll agree to disagree, shall we?

Cheers and best wishes

[Jay Zone]

You said: "RFT probably would not have prevented that accident. "

Test from Goodyear to Pirelli demonstrate that you are incorrect. The rapid lost of pressure and the resulting separation of the sidewall from the rim is what causes the loss of control. RFTs are designed to prevent this.

Next you said: "That isn't their primary purpose."

Actually it is. RFT are the result of a Firestone blowout rollover a while back. RFT were designed to prevent this from happening. We should avoid defaulting to absolutes in a debate. We are simply talking about improved safety.

You said: "So pointing to a terrible accident and saying "Look what happened to a guy who didn't have RFT" is not accurate."

Your incorrect. I never said anything about the guys runflats. Simply an example of a blowout and the loss of control that can result.

You said: "You didn't answer my questions from the video you presented: "

Correct. I didn't because I did not believe it to be relevant. Whatever the condition of his tires or POS it is an example of a blowout as stated above. RFTs are designed to mitigate this.

I must repeat my original statement. Your decision all depends on how much safety you are willing to sacrifice. There are no absolutes so they should be left out of any discussion. I decided they are worth the minor inconvenience since I am not on the track, drive a very small, open top vehicle, sometimes at rather highspeeds

Safety rules but we have to have fun sometimes.

Just something for all Z owners to consider.



Peace
JZ

[Darbs330]

Clearly the RFT vs non-RFT debate will continue for some time.

While hesitant to enter the debate... I thought I'd offer my 2 cents (admittedly, at today's valuation, not worth much).

First about the tires...
- I'm disappointed with them.
Like many others... I find them loud, hard and not very grippy. My disappointment is compounded due to the fact that I fitted my '04 330cic with Bridgestone Potenza's (Non-RFTs) which I love.

That being said... this is my first car w/o a spare & I can appreciate the confidence they instill.

So... I'm conflicted & haven't chosen a side. Instead, I'll decided among replacement options when necessary... living with these until then (perhaps they'll grow on me).

What really prompted me to write, however, was the use of that disturbing video as an example of what can happen without RFT's. (with all respect)

Unless someone has seen the accident report... there's no way you could conclude that with certainty. In fact, other than the video's title, we don't even know (with certainty) that it was a blow-out... much less what kind of tires the poor soul was on.

Perhaps the person was simply (texting, eating, talking, reading, or otherwise distracted)... hit the road debris... lost control... and most likely lost their life.

What if we learned that the driver was on RFTs??... should we then draw the conclusion that RFTs cause loss of control at high speed, after hitting road debris?

I'm all for examining research about RFTs... but let's look at REAL evidence, not simply sensational videos that conclude nothing while frightening the less discerning.

(I'll now - respectfully - back away from this debate with the tag line from my first car brand - MG)

Safety Fast

[Rafale]

Originally Posted by teagueAMX

I did not deny that RFT are intended to reduce the impact of a blow out, as noted in my statement that you quoted. But I also remember reading that press release when it was originally published. It was a tour put on for journalists, and in fact not a test conducted under controlled conditions.

As far as the Youtube video is concerned: Just because I said it was a POS, doesn't mean that accident would have been prevent by RFT. You didn't answer my questions from the video you presented:

• What were the conditions of his tires?
• Were they under inflated?
• Were they over inflated?
• Was there decent tread life on the tire?
• Was there pre-existing damage to the tire sidewall?
• How fast was he going?
• Did he exceed the speed rating of the tire and did it overheat?

Any of those same questions could be asked about a RFT blowout. And my last point was that you point to a terrible accident and say "Look what happened to a guy who didn't have RFT" but you don't know that his car wasn't equipped with RFT.

Are you suggesting that RFT guarantee no blow outs? Of course not! Sure, one can say there is a reduction, but how much? Is there a 1 percent reduction, 5 percent, 10 percent, 15 percent, 20 percent, 50 percent, 75 percent? Nobody can answer that question.

So it can be said that RFT may help prevent serious accident during a blow out, but nobody can say how much they reduce the risk because there are too many variables. Then it's no different than any other risk analysis: cost of prevention vs availability of resources vs practicality of implementation vs probability of danger vs frequency of risk. The bottom line in risk prevention, especially with driving a car, is a practical matter, not scientific.

To sum it up, although I appreciate your argument it's basically an emotional appeal. I have to ask: how much risk do you feel stepping out of your front door going to work, getting on a plane, having surgery, playing aggressive sports, or the big one: why do you drive a sports car?

I think we'll agree to disagree, shall we?

Cheers and best wishes

+1.
There is no denial that there is some minor safety advantage to the RFT. But not nearly as much as for features like DCT, ABS or an airbag but the cost for now in terms of driving pleasure, pricing, availability far outweights the advantage. The video has very little significance to me for all the reason Teague mentioned.

[BlueZ4AZ]

No, they are not that bad.

[cdeslandes]

Originally Posted by Jay Zone

Much less likely but at speed????
Airbag didn't help this gentleman.

Peace
JZ

Airbags can't do much if one gets hit in the roof...

In fact front airbags only reduce fatalities 6% for people wearing seatbelts. They're mostly for the idiots not wearing seatbelts.
Now side airbags are another matter, and are much more useful.