Either those members are making the stuff up or their "GY Shop" is giving them the wrong information. I've read Goodyear's procedure for repair of EMTs. It's in documents that all Goodyear dealers have. The fact that the article discusses a tire repair done to an EMT by a Goodyear dealer totally refutes what those members or their "GY Shop" claim.

 

What GY is telling members is that once the tire has been damaged by a puncture and repaired to hold air, the tire no longer carries the original speed rating or the 200 mile runflat capability the tire has when new. You can go ahead and use the tire for normal legal highway driving while the tread lasts.
Unfortunately, the way that is explained by the tire shop employee, and the way it is understood by the tire owner may not always allow for accurate communication between the two. And then you have a forum members opinion of what he was told posted here on the forum for us to interpret.
Sure hope you understand what I am thinking.

 

For the most part, Mike Mercury's comments have to do with the practicality of needing runflats able to go 200 miles. For the majority of us, we will not need to go 200 miles before we are able to do something about a flat. What do you do in your other cars when there is a flat? You put the spare on and then as soon as possible, get a new tire. Its exactly as Mercury said--you don't ignore a flat... (Its only the really ghetto folk who run on a spare forever.)

So the questioned the validity of the article written by Mr. Halverson. Big deal. I'm sure that the article has merits (and what Mr. Halverson mentioned as critical points are well taken facts) but a healthy dose of doubt keeps folks safer and keeps us from getting shammed. The reason people are questioning the validity of the article is that it says that Corvette and Goodyear are clearly "industry leaders as far as runflat tires go." And throughout the article, the main qualification for "Goodyear" to be the leader is that it meets Corvette's spec on the runflat. It mostly discards all of the other ways in which we judge tires--ride comfort, noise, handling, etc. Additionally the other reason that people might say that Mr. Halverson's article favored Goodyear. A portion of the article questions the other tire manufacturers abilities to create a tire that could go as far as a Goodyear runflat and bascially suggests that the other tire manufacturer do not have the capability to do so. I don't think that this is fair. Third, somebody might think that the article is pro-Goodyear is because of the the sheer amount of Goodyear talk in the beginning of the article.

Mr. Halverson states that they contacted the different tire companies for comment and tht the companies refused. Are we to believe that the only reason that the other companies didn't comment was because they wanted to hide the fact that their tires did not meet GM's spec? That rules out many other possibilities without giving them consideration. Lack of response by other companies does not increase the validity or objectiveness of a study/comparison.

Mr. Halverson's response to Mike Mercury's article states, "All Goodyear did was develop a tire that met that specification." I think that there's a little more at play than that. Goodyear got the chance to sell Corvette (per the article) about 850,000 tires for the C5... I think that there was a little more to it than just developing a tire to Goodyear's spec... Entitling the article "runflat facts" without a complete and proper comparison and assessment of all available runflats is an injustice to the other tire manufacturers.

Lastly, the article claims that none of the folks discussing runflat tires and saying negative things (flame thrower wielding internet forum goers) about the Goodyears do not understand the reasons that the Goodyear is noisier and rides rougher. I beg to differ here. If you read the posts here carefully, most of the forum members are well aware of the fact that Goodyears can go 200 miles flat. And the ones that don't usually ask.

For the record, I don't have any affiliation with any tire company... Heck, I plan to get Avons as my next tire... I'm just trying to keep things honest and real. I've noticed that there are some folks on our forum who are too eager to believe what's in print--heck I do it all the time... I'd say that we take a step back and think critically.

Mercury and Halverson's posts are below if you want to look them over.
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I was the author of the article being discussed in this thread.

"Mike Mercury" either was unaware of or chose to ignore some facts.

1) The 200 miles of run flat travel for the second generation EMT (the C5's Goodyear F1 GS EMT) is not a Goodyear specification. That is the specification General Motors set for the tires on 97-04 Corvettes. In fact, the spec. is 200 miles, at 55 mph, in 77 deg. ambient temperature at zero pressure. All Goodyear did was develop a tire that met that specification.

2) The critical points in my article were a) no other tire manufacturer makes a run-flat for C5s that meets that GM spec and b) two of the three aftermarket tires (the Firestone and the Yokohama) must be discarded after any run-flat use and cannot repaired regardless of the distance driven with no or very low pressure.

As for the belief by some that 200 miles is too stringent a requirment, appearently, GM agrees. The spec for the tires on C6 (F1 GS EMT 2 and F1 Supercar EMT) has been reduced to 100 miles.

The opinion was expressed that my article was an informercial and not an objective comparison.

I beg to differ.

Every tire manufacturer making run-flat tires in the base C5 sizes at the time the story was researched last summer was contacted and offered statements and comments. When those statments made it clear that the Goodyear was the only tire that met the car manufactuer's specifications, that was the EMT we tested in the story.

All three of the tire companies (Bridgestone-Firestone, Yokohama and Michelin) which do not make tires meeting the GM spec were offered additional opportunities to answer questions about why their tires don't meet that specification.

In all three cases, the companies refused further comment.

 

Hib did point out in his article that the speed rating may be reduced by a puncture so that's not the point of my comment, and I certainly do not mean to put anyone on the spot - Hib is just a messsenger. But the message and the reality don't seem to match up...

2) The critical points in my article were a) no other tire manufacturer makes a run-flat for C5s that meets that GM spec and b) two of the three aftermarket tires (the Firestone and the Yokohama) must be discarded after any run-flat use and cannot repaired regardless of the distance driven with no or very low pressure.

While it sounds like a durable, repairable tire - especially against the competition that is not repairable, the net is if it is no longer rated for the speed that the other 3 tires mounted on the car are rated for, and if they no longer warrant it for run-flat capability (may or may not be true, I don't know), does that mean its still fit for the purpose it was originally intended? Sounds to me like this part of the message may be more marketing spin that practicle value unless your daily driver takes the same size tire as your vette, as I am sure GM and GY would have an issue recommending that anyone run with 3 tires at one speed rating and the forth at a different one on a high performance car - even if it is only driven at legal highway speeds, whatever those are.

I didn't post this to start a debate, just to make an observation and to get Hib's thoughts based on the insight he got from his research - thanks Hib, your article and response were very helpful.

 

... and I'm sure that if GM had specified 225 miles at 62.3 mph in 81.6 deg ambient temperature, Goodyear would have said "Yup, this baby is the 225 miles at 62.3 mph in 81.6 deg ambient temperature EMT".

P.S. I am not knocking the very knowledgeable Hib or his dedication and loyalty to us Forumites, just poking fun at marketing practices with which I am very familiar.

 

Thanks for the good info.
Haven't decided on which replacement to get, when the time comes...
As far as being noisy... can't be heard over the "Stingers"...

 

ttt

 

Real good article and study on the EMT although nothing real earth shattering as far as info goes. I have to agree with Paras on this quote from the article:

"While some Goodyear vs. Michelin vs. Firestone vs. Yokohama run-flat discussions on Internet forum sites and mail lists have sparked brutal flame wars, none of those wielding the flame throwers understand why Goodyear EMTs are noisier and may ride a bit more harshly."

I did not realize how stupid we all were, oh well.

 

 

Very informative article, Thanks and keep up the good work!
I will continue useing GY EMT tires, they meet GM spec, and the C% suspension was designed to work with this type of tire.

 

I had a flat about a year ago on my left rear tire. Ran over a nail near my house. The next day, when I turned the engine on, the DIC told me I had a flat. I pulled out a huge nail from the rear tire. Well, I wasn't about to trust anyone with my vette except my dealership which has an excellent corvette mechanic. Its 55 miles away though. I drove all the way there without incident. You could definitely feel that the tire was not right and it made alot of noise on the highway. You could even tell which tire was making the noise from the cabin. The mechanic patched up the tire without any problems and today, I'm still using that tire. Even took it autocrossing after that incident (shouldn't have really done that but there wasn't any problems).
I'm hoping GM will come out with the EMT 2's in C5 sizes soon before my tires go bald. They still have alot of tread after 21k miles of high speed runs, crappy NYC roads and the occassional baby burnout.

 

No one seems to have brought up the question of running slower on runflalts; would driving at lower speeds improve the repairability of the GY or Michelins runflat tires?

 

All very interesting.

BUT . . .

IMHO the Goodyear EMTs are a travesty of a tire to fit to a performance vehicle. They're as hard as concrete and have almost zero wet weather grip compared to a 'proper' tire, you know the sort that doesn't have a side wall made of billet steel. A puncture repair kit a la Z06 has got to be better.

I ditched the Goodyears on my first C5 as soon as I could reasonably make the excuse to she who must be obeyed that they needed replacing for safety reasons. The EMTs on my current MN6 are going to go the same way, but the cursed dealer put new ones on it before delivering it to me.

I can't wait to get some Michelins, Pirellis or Dunlops and really start pulling G's in the corners and stopping properly . . .

 

ya know what... F runflats.




...watch, i'll pick up a nail tomorrow.

 

I agree with Paras reply above about Goodyear tires -

"It mostly discards all of the other ways in which we judge tires--ride comfort, noise, handling, etc"

I just bought a 98 conv with new Goodyears and can't wait till they wear out so I can get something decent. My previous 89 Vette had Goodyears - when I changed them out it was like getting a new car - big difference.

 

BIG TIME!

 

Boy ain't that the truth.

 

Hib, I have been a faithful reader of anything your have ever published... and read your posts on this forum. And will continue to be.

Sorry dude, but this particular article looks like an infomercial for Goodyear to me.

 

I did not read all of the post. Run flats are here to stay.. The second generation run flat is not a 200 mile tire. It's a 100 mile tire..
and for this trade off they offer a softer and mor quiet ride..
much engineering goes into the EMT's... A GM survey done last year of loyal C5 owners and corvette enthusiast say they want emt's but they want them quieter and more sure footed..
GY met this challenge with the second gen EMT.. by dropping the 200 mile rating at 0 pressure to 100 miles..and now offer two tread compounds.. one for touring and one for performance..The C6 Z06 will be run flat.. offered only in the performance compound.
Standard C'6 without mag ride will get the touring compound.
I hope this adds to the insanity.,

 

Good post. Thank you for the info.