Dunlop GPA211 rears tearing at the Seam...

A

alphamale

New Member
I've had a real problem with GPA211 rears with plenty of life left in them tearing from one side of the tire to the other. It always looks like the rubber is being sliced with a razor blade.

Some folks have said this happens when you flip a tire, but I have not flipped them.

I've continued to ride them without any catastrophic failures, but whenever I show folks that don't ride Dunlops they look at me like I am :wow: crazy.


What's causing this? Should I be worried?


Oh and despite all this... thanks for making an amazing tire.
 
sobottka

sobottka

New Member
sup alpha! :D most likely poor set-up, if it tears from the edge to the center on both sides. probably multiple set up problems. you could try a pound or two of extra pressure, this may help but wont fix poorly tuned suspension
 
A

alphamale

New Member
sobottka;188631 wrote: sup alpha! :D most likely poor set-up, if it tears from the edge to the center on both sides. probably multiple set up problems. you could try a pound or two of extra pressure, this may help but wont fix poorly tuned suspension
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Hey man.... I don't think that's it but thanks.

The tire WEAR is perfect.
 
sobottka

sobottka

New Member
alphamale;188584 wrote: I've had a real problem with GPA211 rears with plenty of life left in them tearing from one side of the tire to the other.

alphamale;188635 wrote:

The tire WEAR is perfect.
Click to expand...
:dunno:
 
A

alphamale

New Member
sobottka;188640 wrote: :dunno:
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Maybe I shouldn't use the word tear. It's more like a cut, along the seam where the ends of the rubber meet. It's as if somebody cut the tire using a razor blade from one sidewall to the other.

It's also definitely not being caused by debris. (i.e. Sharp rocks or something)
 
lemondrop

lemondrop

Professional Asphalt Surfer
i had this happen on 209 that i used to run. Good wear, just looked like someone took a box cutter to it
 
Dave561

Dave561

Control Rider
Director
I've not had an issue with mine unless flipped and of course the manufacturer doesn't recommend running them backwards. Ultimately race tires are meant to do 30 laps not 3 days so we're all too slow.
 
moonbeam

moonbeam

New Member
Mine did the same thing . I talked to Sabastian Mincone Road race Manager for Dunlop . He said althought this is rare , there should not be any problems . He said that they had tested them (split tires ) on the dyno at 200+mph with no problem. He said that GPA use a diffrent glue than the NTECs thanks to the EPA.
Hope this helps .

Moonbeam
#50
 
Meat

Meat

Member
moonbeam;188705 wrote: Mine did the same thing . I talked to Sabastian Mincone Road race Manager for Dunlop . He said althought this is rare , there should not be any problems . He said that they had tested them (split tires ) on the dyno at 200+mph with no problem. He said that GPA use a diffrent glue than the NTECs thanks to the EPA.
Hope this helps .

Moonbeam
#50
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I think 'rare' is a very subjective term. I really like Dunlops but have seen too many GPA's split for me to consider it rare. Doesn't happen often, but I wouldn't go so far to say rare.

That being said, I have run the GPA's with a big transverse split in them with no problem at all. Heck, my butt can't tell the difference between a split GPA and a non-split one.

Maybe Dunlop should market the split as a transverse cooling channel that helps cool the tires in long high lean angle turns.
 
Joe Vital

Joe Vital

Member
alphamale; my question of date codes goes to how they might have been stored over this past winter. if it is the glue this may be a storage problem. extreme fluctuations in temp may cause the glue to expand and contract causing the seperation at the seams. of course i can only speculate as i have no first hand knowledge of how the tires are constructed.

my direct experience:
in 2004 or 2005 i had a set of dunlop 207s (??) seperate circumferentially, as if someone had held a razor to the tire and spun it. it was not real deep and didn't get any worse after one session at jefferson. it was replaced with out question by the nesba vendor.

as stated this is 'rare' per dunlop. does anyone, i wonder, have any first hand experience with other brands doing the same thing? i have heard that a few winters ago there was someone that had tires stored in an unheated garage. those tires cracked and split. presumably due to very cold temperatures.
 
Matt H

Matt H

New Member
I have seen the Dunlops do exactly what you are talking about Nate, but when flipped. Exactly as you describe - looks horrible, deep and straight across the width of the tire, and at an angle into the tire (not small, random direction cracks). Never, in my experience, when not flipped. And 80% of the time when flipped. I flip all of my tires, and have run them with this seam separation with no ill effect on handling. I'm not officially recommending this to anyone. Just sharing my experience.
 
moonbeam

moonbeam

New Member
Meat;188711 wrote: I think 'rare' is a very subjective term. I really like Dunlops but have seen too many GPA's split for me to consider it rare. Doesn't happen often, but I wouldn't go so far to say rare.

That being said, I have run the GPA's with a big transverse split in them with no problem at all. Heck, my butt can't tell the difference between a split GPA and a non-split one.

Maybe Dunlop should market the split as a transverse cooling channel that helps cool the tires in long high lean angle turns.
Click to expand...
:agree:

Rare as in everybody I know that has run the GPA has had this issue

Moonbeam
#50
 
A

alphamale

New Member
Joe,

That may have been the case this winter, for my current set of GPA's, because they were in my garage since September of last year. I ran 2 sprint races on them and then they started splitting when we were at Jennings. I've never seen my garage go below freezing though.

I only ran them Sunday afternoon @ Jennings then all weekend at Summit Point with no real issue besides the mental f#&!.

On the other hand, I had the same issue on more than one occasion last summer where storage shouldn't have been an issue as I bought them straight from the WERA vendor and noticed separation after a reasonable amount of use.

And I haven't been flipping my tires.

Nate
 
Joe Vital

Joe Vital

Member
Nate,
Have you asked Dunlop directly about this? Maybe next time at the track bring the tire over to the vendor truck and show it to them. They should be at Summit for the WERA national later this summer. Not sure when the next day Dunlop has scheduled for NESBA.

These splits, or cuts are not uncommon on tires that have been flipped, so beware that the first line of defence may well be that suggestion. As Matt said and I have observed, flipped Dunlops will split at the seams. You do not flip your tires so another cause is the reason. So I will pose a really dumb question; are they mounted correctly?

As for reasonable tire life. We as track day riders are weirdos to race tire vendors. We are the only humans on earth that expect our tires to last for days, not laps. We have been spoiled in some respect to that end, as there are some race worthy tires that do last for days. What may be happening is that we are asking/expecting too much from a product that just isn't designed to do what we require. The only way to improve that product for our use is to provide feedback to the manufacturer and then hope demand side economics isn't just a theory.
 
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