What’s up with my tire?

McTrackPack

CR #171
Control Rider
Had some slicks that were on the bike (Gsxr-600) when I bought it, Dunlop 448/451. I swapped them out for Q3+ until I got “up to speed” since I was new to track. So put them back on for Roebling a few weeks ago, they were slightly used but looked fine (one track day according to previous owner). After the two days of wear at Roebling I see a “crack” in my front tire that is pretty deep. What the heck is going on with this tire? It looks like this may have been under the surface of the tire and is starting to come through as it’s wearing the rubber off. Safe to use or replace? Any ideas? See pics.
Thanks!
Nick

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McTrackPack

CR #171
Control Rider
Write Dunlop with pics. They stand behind their stuff and if it is a bad one...
Just checking to see if anyone had anything similar happen, have heard people claiming Dunlop slicks can start cracking when stored in freezing temperatures but don’t know what that looks like and I even saw website that sells them stating they don’t ship them when temperatures are below freezing. But it could be bs... new is probably best route to be safe!
 

HondaGalToo

Control Rider
The freezing part isn't bs, any race tire can crack due to freezing. Especially if it's in freezing temps and you drop it. That being said, not sure that's the case with your tire. Regardless, do what others above have recommended.
 

tdelegram

Control Rider
i would consider those dangerous and replace before next outing. Imagine a catastrophic tire failure at triple digit speeds. Replace both to be safe, your life and the cost of fixing a bike is a lot more than new rubber.
 

McTrackPack

CR #171
Control Rider
New set of tires sure is cheaper than wrecking...and since I don’t know where these tires had been before I got them it was probably a bad idea to use them to start with! Maybe I should just get smarter
Thanks y’all!
 

bmart

Control Rider
I think that it is "smart" to be curious and to have noticed the split. It looks like air in the external mold to me, but a Dunlop guy would know better.

Hope to see you "out there!"
 

McTrackPack

CR #171
Control Rider
I think that it is "smart" to be curious and to have noticed the split. It looks like air in the external mold to me, but a Dunlop guy would know better.

Hope to see you "out there!"
I'll show it to the Dunlop guy next time I go just to educate myself. I had carried this set around to several track days just in case I needed a tire and I showed them (front and rear) to two different Dunlop vendors before I put them on and they both said they "looked fine to use". That was of course before the two days I did at Roebling and before the "crack" showed up. But I got a weekend out of them! I do also have a set of super-softs that came with the bike that look like they may have like 2 laps on them but not sure if super-softs is anything to use at a track day since I'm not doing any qualifying laps ;)
 

McTrackPack

CR #171
Control Rider
Possibly dry rot.
A 2019 tire would have dry rot? Hard for me to believe. One Dunlop vendor at “another” track day said it could be due to cold temperatures when I showed it to him. It’s the only explanation I have for it so far. Anywa, I replaced both front and rear with a fresh set but I was curious to what it was.
 

Otto Man

John
Control Rider
Like the others said, hard to say because all we can do is speculate since none of us know the history of the tire. I remain adamant that the tires that are currently on it should never be a consideration when buying a used track bike. A new-to-you track bike should always get a fresh set of tires of your choosing.
 

McTrackPack

CR #171
Control Rider
Yep, I think we’ve figured out that new rubber is the best. And no, I’m not gonna ask what brand of rubber to get because I know this thread will never die then (and I already bought a set)! ;)
 
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