Anubis

iTrader: (1)

It looks to me like I may have a set up defective tires, but I thought I might get some other opinions. I've only done 2 autocrosses and half a track day with them and I can see the joining line where the tire was put together on 2 of the tires, one of which is chunking off in pieces pretty bad and the other is starting to peel apart. Hard to tell from the pictures but I want to know what you guys think. These are Kumho Ecsta v700 that were shaved and heat cycled by tirerack prior to use.


I have sent these pictures to Kumho and they are having one of their engineers take a look at them tomorrow morning. I hope to be getting a replacement so I can get my track day in for October.

jwtodd60

Welcome to the V700 shredders club. I corded 4 V700s last year over the course of a single autocross season, the first two biting the dust after just less than 20 runs. In retrospect (after running Hoosiers at 50-60 psi this season), I think I may not have been using as much air as I should have, but I don't think that's your problem. In fact, I just read an article the other day, in GRM I think, describing your problem.

That line across the tread is the splice where the tread is joined together. The ends are tapered so that they overlap at the splice so that the joint has more surface area for sticking the two ends together. Because of this, the splice is more prone to tearing in one direction than the other. Depending on the car and its particular strengths (power/braking) and its drive wheels (FWD/RWD/AWD) and how you will be driving it, it may make sense to mount the tires in a way that tends to protect the splice from the most extreme forces at that end of the car (e.g., acceleration at the rear of a high-power RWD car and decceleration at the front wheels of a car with really good brakes -- can you say Evo?). Sometimes this will mean running them "backwards" if the tire has a directional tread pattern. The article had a table listing several R compund tires and which way they should be mounted. I don't have it handy right now though...

JW

Neal@tirerack

iTrader: (25)

Exactly correct! Basically the joint where the tread slab is molded together goes against the driving forces. In some cases it can peel back a bit or even rip. We have been told by Kumho that this is ok, and to prevent further seperation run them backwards. This way the splice is travelling with the forces rather than against them.

992gnt

iTrader: (5)

I have a set of pictures just like those. I flipped mine around after the seams appeared at a track day in July. I have since beat the tires completely into submission, and replaced them yesterday.

Anubis

iTrader: (1)

Thanks for all the replies. I just got off the phone with Kumho USA and they are going to replace my tires for me due to the issue. I like the sound of what you've said by having the rotation backwards. 2 questions: (1) would you suggest running the 2 front tires in reverse rotation and putting the back tires in standard rotation? (2) No issues with how the tire is wound / corded by running in in reverse compared to company recommendations? (3) I lied, I have 3 questions: Do others have this problem with the Toyo R1 tires?


Thanks again for the input.

Neal@tirerack

iTrader: (25)

I wouldn't run two one way and two the other. It would be best to have them all rotating the same direction. Kumho recommended to us the solution of running the tire backwards to minimize the possibility of open tread splices. From the memo we have:

While these tires feature directional tread designs, they can be remounted "inside-out" on their wheels and run in the "opposite" direction for use on a dry track if a tread splice becomes visible.

992gnt

iTrader: (5)

Hmm, I guess I should have been more persistent. I didn't get an offer for replacement.

I am glad to hear they are taking care of it for you though.