Kuhmo Ecsta v700

[dknv]

Dean and I changed the race wheels/tires on the red sedan last night, and found a strip of tread, maybe 2" wide and 6" long stripped off the tire (some of it was still hanging there). Tire is done.

I thought I'd read somewhere about other people having this 'problem' on the ecstas this year. I had no problems with the same tire last year, but now I'm wondering what Kuhmo changed with their latest batch.

[sperry]

Originally Posted by dknv

Dean and I changed the race wheels/tires on the red sedan last night, and found a strip of tread, maybe 2" wide and 6" long stripped off the tire (some of it was still hanging there). Tire is done.

I thought I'd read somewhere about other people having this 'problem' on the ecstas this year. I had no problems with the same tire last year, but now I'm wondering what Kuhmo changed with their latest batch.

Kuhmo now recommends that the Ecsta v700's be shaved unless you plan on using it as a wet-only tire. I guess the compound just can't handle the heat and will chunk/shread unless it's water cooled, or shaved. The older Victoracer v700's are not affected, since they run a slightly harder compound. Lots of people's reviews were saying that even tho the Ecsta v700's are a bit stickier, the older Victo's are still the better tire overall: http://www.tirerack.com/tires/surveyresults/comp.jsp.

Notice:

The ECSTA V700 must be shaved to 3/32" - 4/32" tread depth for any autocross or track use in the dry.

Kumho advises that the ECSTA V700 DOT-legal competition radial must be shaved prior to use in dry conditions. If this tire is not shaved, excessive wear may occur causing the tire to wear to the cords prematurely in a localized area.

Tire heat cycling will not prevent the excessive localized wear of full tread depth tires but will continue to enhance the tire consistency and wear on shaved tires.

The ECSTA V700 should only be used at full tread depth (6/32") for wet track and wet autocross use.

http://www.tirerack.com/tires/tires....del=Ecsta+V700

[dknv]

Yeah, I'm hating this new requirement. It wasn't part of the spec last year.

[sperry]

Originally Posted by dknv

Yeah, I'm hating this new requirement. It wasn't part of the spec last year.

Yeah, it's dumb... it's like you have spend extra money to have tread taken OFF the tire before you even get to run 'em! I'd just stick w/ the Victo v700's.... that's what I was planning to run if I had stayed in SM. I think the newer Ecsta v700's should basically be considered a rain tire. At least Kuhmo's plans to stop making the Victoracers fell thru and they're still making both versions of the v700's.

You might want to PM Austin (AtomicLabMonkey), he's running the Victo's on his Mustang IIRC.

[dknv]

Dean also just got the Victos (before Hawthorne I think). Also, Tom Miller, the guy who ran the bmw (he normally road races) said in his experience, the victoracers were better than the ecstas.

[sperry]

Originally Posted by dknv

Dean also just got the Victos (before Hawthorne I think). Also, Tom Miller, the guy who ran the bmw (he normally road races) said in his experience, the victoracers were better than the ecstas.

Well, just looking at side by side pictures of the tires, I'd say go w/ the Victos.

Ecsta v700:


Victoracer v700:


The Escta's have those arrow like tread slots. They look like they'd help evacuate water, but anytime you have points into the rotational direction of the tire, that's a good spot for chunking to start. At least the slots don't go all the way to the water trough, or those tires wouldn't last a single autocross run!

On the Victo's, the outer shoulder is basically one big strip. Just a tiny bit of tread for looks. The outer 1/3 of the tire is basically a slick... now that's a better tire, even if it's pretty ugly looking.

[Dean]

Debbie already knows this, but I wore the last set of Esctas on my Stealth from full tread until hey were pure slicks and got down to hard rubber with no lifting as we saw on her tires.

I think there is something wrong with the Ecsta manufacturing process that is making the ruber pull away from the top layer of nylon cord. looking at her tire, i think there is also an issue with keeping the cord at a consistant depth in the rubber. I swaer on her tire, the cord in the area where it pealed is higher then the botom of the circumeral tread groves. that should not be.

I don't think the Victorracers will last as long on my heavy beast, and I already have a set of Toyo Poxes RA1s on the way to try out.

Unlike Debbie, I am not tempted to take a sniff at the Hoosier crack pipe

I wish Michilin/BFG would make the R1as again. they were a great tire for heavy vehicles like the Stealth.

Oh well.

[sperry]

Well, if there was a manufacturing error, you should be able to get a new set of Ecstas (or atleast replace the bad one).... if the cord isn't where it's supposed to be, I think Kuhmo would be interesed in knowing this.

Luke from Tirerack is their NASIOC contact, and I'll bet he can help with getting this solved, since he's supposedly on top of things over there.

http://forums.nasioc.com/forums/memb...fo&userid=1215

Debbie or Dean, you should post this over on NASIOC.. maybe someone there from the wheel and tire forum can help?

http://forums.nasioc.com/forums/foru...?s=&forumid=88

Debbie, got any pictures of the damaged tire? Esp. the "out of spec" cord? That might help spark some responses... usually tire manufaturers and resellers don't like pictures of their damaged products on the web w/o a good explaination.

[Dean]

Technically, they are at or below the wear indicator, so I'm sure that is what Kumho will say.

What doesn't make any sense is why running them full depth would cause seperation. Yes, at full tread depth, they wear the shoulders more, but the core would be much hotter when they are thinner.

I think they were getting a lot of compaints from people running at full depth and getting the scaloping effect on the outer edge, and that is why they say they have to be shaved.

DK wants to take pictures, but I don't know what she plans to do with them.

[sperry]

Originally Posted by Dean

Technically, they are at or below the wear indicator, so I'm sure that is what Kumho will say.

What doesn't make any sense is why running them full depth would cause seperation. Yes, at full tread depth, they wear the shoulders more, but the core would be much hotter when they are thinner.

I think they were getting a lot of compaints from people running at full depth and getting the scaloping effect on the outer edge, and that is why they say they have to be shaved.

DK wants to take pictures, but I don't know what she plans to do with them.

Yeah, the whole "they must be shaved" sounds like a cop-out to me... it shouldn't wear so badly, and they know it, but haven't fixed it yet... so like all companies, they won't admit it's bad until the fix is ready, and even then they'll just say the old one was okay, but the new one is even better.

Look at Ford and the Explorer... since '91 they've known the Explorer needed to be a few inches wider to help prevent roll-overs.... they just now got around to redesigning it that way, and what do they say? "It was for asthetic purposes, the old Explorer is plenty safe"....

[dknv]

Originally Posted by Dean

DK wants to take pictures, but I don't know what she plans to do with them.

I'm going to add it to my driving chronicles.

[AtomicLabMonkey]

Originally Posted by Dean

Technically, they are at or below the wear indicator, so I'm sure that is what Kumho will say.

What doesn't make any sense is why running them full depth would cause seperation. Yes, at full tread depth, they wear the shoulders more, but the core would be much hotter when they are thinner.

I think they were getting a lot of compaints from people running at full depth and getting the scaloping effect on the outer edge, and that is why they say they have to be shaved.

DK wants to take pictures, but I don't know what she plans to do with them.

What I've read, and although I'm no expert this seems to intuitively make sense to me, is that the deeper the tread is on the tire (so full depth vs. shaved), the harder the rubber is worked, hence higher temperatures. Taller tread blocks deflect further laterally with each rotation of the tire, so the cyclical internal working of the rubber generates more heat... and the taller tread block also means a bigger moment arm that the tire forces are acting through, so when it gets overheated it's that much easier for the tread block to start tearing loose from the base.

I decided to stick with the Victo's for my car just because it's fairly heavy (should be about 3500lbs with me in it), and I'd heard from others that the newer ECSTA's were typically better suited for lighter cars that didn't abuse tires as much as Mustangs do. So far they've held up great, and I think they're about halfway used up.

[dknv]

Ok, for this weekend I'll be running the Victo V700's. (Everyone's advice outweighed the temptation of the hoosier crack pipe. :wink: )

[sperry]

Originally Posted by dknv

Ok, for this weekend I'll be running the Victo V700's. (Everyone's advice outweighed the temptation of the hoosier crack pipe. :wink: )

I think that's a wise decision... all the posts I've read say that once you go Hoosier, you never go back... and one set of Hoosies won't last a whole season... it's an 8 tire a season habit!! :shock:

[Dean]

The real problem with Hoosiers is that they have two compounds. A, and R. A is for autocross, and will not hold up to the heat of a 20 minute or more road course session, and the Rs are not as good as other R compound for autocrossing as I understand.

So now you need two sets of wheels to go with your two sets of wear out to fast Hoosiers!

To steep a habit for my wallet.

No thank you.

[dknv]

Originally Posted by Dean

To steep a habit for my wallet.

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