I suggest that all persons considering replacing the OEM (GY) EMT's with another manufactures 'run flats read, very carefully, this article.

http://www.corvetteactioncenter.com/....php?qstId=515

Many thanks to GrayC5 for the original link

 

Good info.Thanks.

 

I read that in another post. Great info to have. I actually wonder if there is really a difference between the Pilot Sports and the Good Years. I will keep this article close at hand though.

 

Does anybody know if you can get road hazard coverage for runflats, so that the tire is replaced free if it is unrepairable? That might be an option and reason for buying Michelin or some other brand that does not have the zero-pressure driving range of the Firestones (according to the referenced article).

 

Good question - hope someone can provide an answer.

 

AC54ME, you're welcome and I certainly agree with your suggestion above.

 

actually, that Hib Haiverson article has been around here once before.

Hib is knowledgeable, but not a God. He places way too much emphasis IMO on the 200 mile run-flat spec by Goodyear. How many here really need to go 200 miles once the tire is flat?
Heck, all I need to do is to run long enough to get off on the next exit, and get it taken care of.

None of the aftermarket run-flats for '97-'04 Vettes are capable of going 200 miles deflated. That got my attention ...

but why ????? Run flats were not designed so the driver could "ignore" a flat. They're supposed to allow you to continue driving only long enough so you can reach a convienent place to get it repaired. And if it's a slow leak, you can always refill the tire and go on your journey.

since the search function is crapped - I can't find the original post. It contained some interesting info that Hib didn't include, and some interesting info from Goodyear about running their EMT's for that long (200 miles) with zero pressure.
Others claimed that Hib's article was more of an info-mercial for Goodyear, and not an objective comparison.

I wish I could find that damned post :

 

Excellent article. It's very interesting that none of the manufacturers replied to the question's to why they don't meet GM spec's and if the purchaser's were advised of this. I also found it very informing to find that the only non-Goodyear run flat that is repairable is the Michelin pilot. To me that doesn't justify the lower price and lower range (50 miles vs. 200 @ 55mph). I'll stick with the Goodyears. I didn't buy a Vette because I wanted it to ride like a Cadillac. I'll take the 200 mile and repairability of the Goodyears over better ride and a 1/4 of the range. Also I heard all the complaints as to the noise the GY's make and I don't experience that myself, anyways just my 2 cents. That arcticle is exactly why I love this forum, bringing important info to the masses.

 

Well said, Mike Mercury. The purpose of a runflat is to get you to a place of saftey and/or a repair facility, and I cannot conceive of where I might drive where I would be more than 50 miles away from a service facility or place of safety or mobile phone cell site. Also, we should keep in mind that the tire dies not disintegrate or explode if you drive it 55 miles or 63.38 miles - they just pick a reasonable number for marketing purposes.

Personally, I much prefer Michelin RunFlats, and I would carry Fix-a-Flat, plug kit, air compressor before I would ever go back to those harsh and noisy EMTs.

 

Thanks for the info. Interesting reading.

 

If you are in a high population area then, yea, guess you would not need the 200 mile spec. Guess you could consider Ohio as high population. But if you are out in West Texas, that next exit where you can get it fixed may be 200 miles on down the road.

tom...

 

If there's no discernable difference in handling with zero pressure, how do you know you have a flat in the first place?

 

That is what the air pressure sensors in the tires are for

 

Ah ... of course ... I was just wanting to see if anyone besides me knew the answer.

I suppose the DIC will ding in that case? Last night, I made a not-so-sharp right hand turn and a ways down the road I heard a funny noise ... the DIC was letting me know my turn signal was still on. It's downright useful, but I didn't hear it right away because the car's so noisy. I guess I'll have to do the sound damping mod next.

 

Great article but I questioned why he couldn't do the test with other manufacturer's tires. I'm sure if he explained his purpose they'd have donated a set. Like Mike M said, I question the motive and accuracy. I had GY's and now have Michelins. I'll bet you $$ non of the others disintegrate at 51 miles. I stuck with runflats so I could get to the next repair facility. Even if I destroy the tire I don't want to be stuck in the middle of no where.

As for the question of a road hazard, I have it for my Michelins.

 

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.

 

AMEN! And thanks for this article, keep em coming. When I am researching for info I want facts first and opinions a distant second (although always appreciated ). For all of you that aren't happy with the GY's and have changed to something else that's great, I may make a change in the future, you never know. But for right now I want and need the long distance capability of the GY EMT and am willing to deal with their shortcomings in other areas. We need technical articles like this.

 

The myth that you are not able to 'feel/tell' when a run flat is out of air is just that - a myth.

I have had a run flat out of air, and part way out of air (both due to 'cuts/nails' in the thread area).

It is immediately noticable that something is amiss. This is more apparent when the situation is in the front tire, however there is no mistaking that something is wrong when it occurs in a rear tire.

Just my $0.02.

Hib Halverson - many thanks for your article, and for your post to this thread.

Very informative.

PS: it should be noted that both my Verts DO NOT have the run flats any longer. I do, however, have the 'emergency' road kit, a cell phone, and a credit card.

Would rather deal with the possibility of having a flat than riding for X thousand miles on the run flats. Just not worth the difference in ride quality.

 

Hib, the only observation I will make is that I have seen several posts from members who are told by their local GY shops that once the tire has been damaged in any way, GY will not stand behind it any longer. This usually is because of a common nail in the tire situation, at least that's what I've seen being reported by several members...

I would be interested in seeing more on the tires under development by Amerityre ( Amerityre.com ) - check out the NBC Video link on their home page...

 

All I have to say about runflats is..

They protect you from a flat slow leak tire but not any kind of blow out.

If you wake up and find you have a flat tire you are not going to drive on it anyways right?

what shops actually carry a run flat in stock around you? You can let your car sit in bfe for a week or pay 100 bux and let it sit in your driveway.

Who said owning a machine would be cheap?