Tire Experts - is this still good?

[DByers]

So I purchased some rims fitted with slightly used Kuhmo V700's on them and have put another 3 track days on the set. After my last event while putting my street setup on for the drive home I noticed a slight slice/gash. Its not deep, maybe 1/32" at best but I was hoping to run these at least one more event. All the other tires have even wear and are probably near perfect as far as grip goes. I was going to run these since I don't drive to the track on them (I pile them inside my 71) but a blow out @ track speeds does not sound like fun to me. This is a rear tire also.

Pics




If you look at the slice it is almost a perfect 90deg to tire rotation. Could it be some sort of de-lamination, or rubber pulling apart?

Any and all thoughts are appreciated.
TIA

[slodave]

Dan, did you post about this before? I remember a thread similar to this and had the same issue. I think the overwhelming response, was to ditch the tire.

Dave

[jonbot]

I don't know anything about using tires for competition, but I did find this page over at tirerack, might be useful.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=161

[john walker's workshop]

i wouldn't run it. local PCA rules also state no cuts or cracks in the tires. wouldn't get through my track inspection.

[Netspeed]

Weird....it's so even across the tire that I doubt it was cut. Did the tire sit while hot on a loading ramp of a trailer? It might have put a crease in it. It would have a pretty good bulge if it was structural. I'll see if I can get my friend to take a look at the pic.....just for curiosity's sake.

I agree with John...I wouldn't run it on the track. Save it for an autocross....

[DByers]

Thanks guys for affirming my gut feeling. Street tires for the next few events for me.

Dave, this is the first I have posted on this. Noticed it after a session at streets.

jonbot, That page was very useful, thanks!

Netspeed, No trailering for my car. I haul the tires in the passenger seat and trunk then change them at the track. I have switched the rears and fronts from drivers side to passenger side after the first 2 events. I guess I should not complain as the rims and tires were cheap enough when I bought them that getting 1 track day was more then my $ worth.

JW, As usual your advice is sound and taken.

Thanks all. I will pull the tires off and sell the rims.

[J P Stein]

That appears to be a belt joint separation.....where the two ends of a layer of rubber meet.
I'd run it for AX, but not on the track.

[Netspeed]

Here's what my buddy said. He's got over 20 years of tire-industry knowledge:

"Tire is fine. Its just in the tread so no structural integrity is lost. If the cut extended into the belt package it would be a problem. The rules are there for safety issues but this is just in the soft(usable) part of the tire. I think with another go 'round the "cut" will disappear. "

[450knotOffice]

Personally, Dan, I wouldn't risk it. If I were you, I'd use them for Autocross, as J P Stein mentioned, but I wouldn't want to be loaded up at about 120ish through turn 8 at Big Willow and have it go. That would be really ugly, at best.

[Por_sha911]

I know nothing about tire engineering but I am sure that if you run that tire at the track you will be wondering if you made the right decision and will have a harder time keeping your mind focused. For that reason, I say don't do it.

[3.2 CAB]

DO NOT RUN THAT TIRE!!! That tire is loosing the tire tread belt. It could peel-off in one long piece the next time it gets hot. Then you can have a 20 pound "band-aid" missile flying around below your oil lines, oil tank, etc., and then possibly removing said items, that it might hit. But, it is your car, but the other people that may be in the range of this flying decapitation device, would probably appreciate it if you stayed at home that day, OR not use the tire. If one of them is doing this, I would advise to really EXAMINE the other tires, to check for this SAFETY DEFECT!!

[hcoles]

the thread was mine... I called Kuhmo and they said it was fine to run on the track. Your "cracks" look a bit bigger than what I had.. I would call them and if necessary send them the picture. I ran a track day with two drivers when my tires had the smaller cracks and they don't look any worse.

[pitargue]

I believe Kumho had a recall due to this. But it was 3 or 4 years ago if memory serves.

A couple of years ago, a friend had some V700's do this while on the tires for the first time. I believe Kumho replaced them under warranty.

I wouldn't run them...

[KTL]

More information about tread splices

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=160&currentpage=161

Also, the Kumho recall was the Ecsta V700, not the Victoracer V700. Different tire that what is shown on this topic.

[hcoles]

the small slices I have are on Victoracers... Kevin, thanks for the link... good info.
I'll watch very close...at this point .. I'm due for a new set anyway... I've lost track of how many track days are on this set.. I've flipped them on the rims one time.. that could have caused the small cracks to come out sooner...

[slodave]

Originally Posted by hcoles

the thread was mine... I called Kuhmo and they said it was fine to run on the track. Your "cracks" look a bit bigger than what I had.. I would call them and if necessary send them the picture. I ran a track day with two drivers when my tires had the smaller cracks and they don't look any worse.

I knew I saw a previous thread on this. I was thinking about going into the fortune telling business for a moment!

[pitargue]

Originally Posted by KTL

More information about tread splices

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=160&currentpage=161

Also, the Kumho recall was the Ecsta V700, not the Victoracer V700. Different tire that what is shown on this topic.

Thanks for the correction. I guess my memory doesn't serve.

[Ray B]

How confident on the track are you going to be with questionable tires?

[ischmitz]

Looks like Kevin nailed it with the Tire Rack link posted - follow the insructions and you shold be fine.

[DByers]

Thanks again for all the info. I will probably use them for an A/X this April and see if the gap closes. Wont run these at a track event, just does not feel right.

Ingo - Call me when you can this AM.