What do you make of this tire?

Well, I'm three days away from a double race weekend, and as usual I'm behind. I didn't check the car out directly after the last event like I usually do, and am just now getting it looked over.

I've found problems with two of the four Kumho ecsta v700's. These tires have four races, four practice sessions, four qualifying sessions, and about four additional hours during a practice day.

Two of the tires have triangle shaped chunks out of the middle (see pictures). One of the two is showing cord in this area, the other one is not showing cord but you can see the outline of the cord under the rubber.

I have one spare new shaved and heat cycled tire I could use to replace one of these two tires. However, I doubt I could get any additional shaved tires delivered, mounted and balanced in time for this weekend.

Given my business travel schedule this may very well be my last race of this year. I plan on buying four new victoracers during the off-season.

Would you race on these tires? Maybe check it closely after each session? If I have to buy four new tires now (and pay expedite fees, shipping fees etc) I'd probably just not do this race. I do have a set of full tread rain tires but I'd rather not ruin them if possible.

What do you think?

Tire #2
http://waynef.smugmug.com/photos/6618770-Ti.jpg
http://waynef.smugmug.com/photos/6618775-Ti.jpg
http://waynef.smugmug.com/photos/6618774-Ti.jpg

Tire #1
http://waynef.smugmug.com/photos/6618773-Ti.jpg
http://waynef.smugmug.com/photos/6618771-Ti.jpg
http://waynef.smugmug.com/photos/6618772-Ti.jpg

Wayne, What pressure's do you run? Those look like over inflatted heat blisters. What kind of car?

I wouldn't run them with chunks and cords showing. Life is too short to race on known "BAD" tires.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html

Wayne,

As tough as it is to sit out a race, I wouldn't race on them.

It seems to me you have plenty of time on the tires, I'd doubt that you could safely get another double weekend out of them. Wouldn't it suck to enter the race and get a DNS along with wasted travel, wasted entry fees and wasted time? Worse yet, have a failure, whack a wall or other competitor and be out a whole lot more than a set of tires. Either bite the bullet and get the tires you need expedited, next time check your tires, brake pads and other wear items much sooner. Probably doesn't need to be said, but we have ALL been there.

Do you have tire support at the track? Perhaps you might have to pay a little more for the tires, but you wouldn't have to stress about getting them shipped on time and mounted. Any of your fellow racers have a set up take-offs that they would let you use in an emergency, if need be?

I run 28/30 cold, sometimes 26/28 depending on the tire temps and such. This is on a Camaro. It's the same pressures I've been running on this car for the last 4 years on Kumho victoracers, and have never had a problem like this. I also was getting much better tire life out of the victoracers vs the ecsta's.

There is no tire support at this race, or anywhere near this race. Nobody within several states does the shaving.

Maybe I'll just put the car away for the year and go trap shooting this weekend...

Wayne

I would have to say that the Ecsta's aren't the same as the Victoracer's, and If you've run the Victoracer's the last 4 years, go back to them.

Have you tried any other tire on your Camaro? Hoosier, Toyo, or the new Avon?

I assume that you run different front's than rear's? Were these the front's or rear's?

Racing is a risky sport even when everything is 100% correct. If you know that you have the potential for a blow-out of some other tire related failure, why increase your risk?

Stay home, or go crew or flag that weekend.

Tim

Just got off the phone with tire rack. They don't have any tires in stock at either their Indiana or Vegas warehouses. If they did he quoted me $300 to get it here by Friday.

As I mentioned I do have one new tire I could use to replace the tire that has the cords acutally showing. I'm just not sure how much longer the other tire has before the cords show through on that one as well.

I just noticed those pictures I posted are incredibly small. Go to this gallery for much bigger close up shots. You can select a larger size for a close up of the chuncked area.
http://waynef.smugmug.com/gallery/175796/1/6618773

Quote:

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Originally posted by racer_tim:
Have you tried any other tire on your Camaro? Hoosier, Toyo, or the new Avon?

I assume that you run different front's than rear's? Were these the front's or rear's?

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Up until this year, I've only used the victoracers on this particular car. Mostly because I've had such good luck with them.

We have to run the stock size tire on all four corners, 275/40 -17. The two chunked tires are off the front, which is not surprising as they take a pounding with the weight of these cars. Particularly at the track we were at for the last race (and the upcoming race this weekend).

Wayne

Have you tried Vilven tire? I received my last set of Victo's in under 24 hours and they were the same price shipped as Tire Rack

I've had good luck with my Ecstas... I think I've heat cycled them to death and they've still got meat left... they might not do to well with heavier cars...

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Scott Rhea
It's not what you build...
it's how you build it
http://www.izzyscustomcages.com/images/IzysLgoSm.jpg
Izzy's Custom Cages

No, I would not race on those tires on a Camaro. Those chunked out areas will grow quickly.

Looking @ TireRack for a 275/40-17 tire, Kuhmo has both the 700 and the 710. The 710 looks more like a Victoracer than the Ecsta 700.

Avon = $203 avail immediately
Hoosier R3S03 = $246 low stock
Hoosier R3S04 = $236 special order
Ecsta 710 = $191 avail 8/8

Tim

"These tires have four races, four practice sessions, four qualifying sessions, and about four additional hours during a practice day."

Are you kidding me?!? You got the equivalent of 20 sessions out of them! They are simply used up. You got your money's worth; buy another set. Try Hoosiers and then you will count your blessings. :-)

I agree with the comment about Vilvin-they give great service. Try them. Their number is 800-251-0017.

Dave Piasecki

Interesting, I had one of my relatively new shaved and heat cycled kumhos from Tire rack do something similar after 7 heat cycles last week(1 qual, 3 races, 3 test&tune sessions). Also the tire has developed a deep crack running across the width of the tread. Looks like the tread was getting ready to delaminate. Pressures were never above 38-39psi hot and temps never measured over 180-190F. The three other tires look nearly new. I am done running the Kumhos until I get an answer from them as to what caused this. I ran a set of full tread depth Kumhos to 20+ heat cycles on the same setup and they look just fine, and those tires saw higher pressures and temperatures.

Back in the game...

Ok, I "borrowed" a set of tires for this weekend. They seem to be slightly softer then a rock at 78-80 on the durometer, but at least they are not corded.

Wayne

Congrats,

Hard as a rock tires can really be a good learning tool...be smooooooth

Quote:

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Originally posted by fingaz9:
Also the tire has developed a deep crack running across the width of the tread. Looks like the tread was getting ready to delaminate.

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See the latest Grassroots Motorsports Mag. Very indepth article if I'm reading this right....

I've always gotten well over 20 heat cycles on my Kumhos......... Also ran them on a 2800lbs, RWD car and never corded or chunked.

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Jeff L
#74 ITB GTi