Maladin's tire

[spyderchick]

I was mounting up a race castoff (dunlops) on my street bike and saw the same thing...we had to scrap the tire...interesting....

[SliderPhoto]

I have personally seen 4 Dunlop 208GP's develop what looked to be a cut/crack perpendicular to the rotation of the tire on my friend's bikes from a trackday.  The worse of which split open enough to see the belts under the tread.  They were running proper air pressure and overall the tires looked good with the exception of the cut/crack.  None of the other brands of tires at the track on those days showed any abnormal features so I'm assuming it was a deffective batch.  I hadn't run Dunlop's up to that point and after seeing that I'm pretty sure I won't.  

I had that happen to a set of 208s last season. The  response I got from the tire guy was, oh that happens and it will be fine. I was at Brainerd and with the speeds of T1 I didn't feel comfortable running that tire.  

[spyderchick]

I had that happen to a set of 208s last season. The  response I got from the tire guy was, oh that happens and it will be fine.

Ask him if he'd be willing to run the tire himself. Unacceptable. Completely unacceptable. We want tires we can be confident on. Yeah, Turn 1. Brainerd. Didn't duhamel have his "skirt fly up over his head" there? No need for good tires at all. Jack, you just ask too much I tell ya.

[tigerblade]

Hmm...  I ran 208GPs at VIR for two trackdays, and I have a little slit perpendicular to the tread pattern too.  WTF?!  I liked the tires a lot but that's really weird.   :o

[r6_philly]

Funny, mine was at VIR too. I bought the brand new 207GP, had them mounted it. Ran 2 races, and there is 3 inch long crack across the tire. About 1/2 inch deep. they tried to tell me that it was a cut from debri. Also said, if it gets any worse I can always 'get' another one. I wasn't going to buy a new tire because it cracked within 14 laps.

that was the last time I ran dunlops. So far I have used over 10 sets of Pirellis, no abnormal wear/tear whatsoever.

[xlr8tn]

I had that happen to a set of 208s last season. The  response I got from the tire guy was, oh that happens and it will be fine. I was at Brainerd and with the speeds of T1 I didn't feel comfortable running that tire.  

I had the same thing happen to me on last years GP208's.  I had one session and came back in to the pits to think I ran over something.  I took it over to the tire guy and he kept reassuring me that it was ok and they see it often; another expert racer confirming in front of the tire guy that it was ok.  I came back later and stated again that I was uncomfortable running something with a big slit from wall to wall.  He changed my tire, but stated he wouldn't do it again if it happened because it was totally safe???  If it happens again, i'll be looking for another brand of tire.  He also stated I should be using the GP208A's and should upgrade.

-brent

[Nate R]

I have a small slit on my rear tire. it's not beyond the depth of the wear bars, but it's there. Probably about 2" wide. I have little problems with that, mentally. This may be happening on the Dunlops, but at the club level, who's shredding tires because of it?  I don't see the tires failing, and I'll continue to use the tire.

Interesting. In fact, this Reassures me, because I thought I might've ran over something, and have a slow leak. But, in fact, it's a normal thing. BTW, this is on my new 207GP 160 rear.

If it were down to the belt, or edge to edge, well, that might be a different issue.

[duc995@aol.com]

I had a new set of Dunlop 207 GPs develop an inch long slit in the SIDE WALL tangential to the rim...very scary and the Manufacturer replaced it at their cost.  I have never had these kind of problems with Michelins, and chunking and failure (explosive) aren't in the same ballpark. :o

[tzracer]

The 'crack' you are seeing is the end of the rubber. Rubber is wound onto the tire. You are seeing the end of the winding. Also the tread of the tire does not hold the air, there is a layer of rubber on the inside that retains the air.  I have had it happen on a few bike tires and on many kart tires with no problems.

[r6_philly]

The 'crack' you are seeing is the end of the rubber. Rubber is wound onto the tire. You are seeing the end of the winding. Also the tread of the tire does not hold the air, there is a layer of rubber on the inside that retains the air.  I have had it happen on a few bike tires and on many kart tires with no problems.

This is the case. However, it does not inspire confidence that the tread rubber won't just disintegrate and fly off as a whole, such as the Firestone fame. I presume the end of the rubber unwound because of the wear and high operating temperature. Common physics would dictate that more wear and tearing between the body of the tire and compound will develop with continue usage. No it does not retain air, but if the tread does fall off, I think you are going to crash. If the adhesive thats bonding the end of tread rubber can deteriate and fail, why wouldn't the adhesive that bonds the tread to the body fail in the same manner.

If I walk to your pits and use a utility knife to cut a 4 inch long, 1/4 inch deep gash on your rear tire, would you not mind and go out and race on it?

[tzracer]

I was only trying to explain what was happening. It is up to the rider to decide if they want to ride on the tire. I have used such tires. As log as no cord is showing, i used the tires. What is happening is not tread seperation (what happened to firestone). The rubber is supposed to join with the other layers during vulcanization, no adhesives are used. Cold tearing can look similar, but happens in more than one spot.

[r6_philly]

Adhesive does not hold the tire together, the vulcanization of the rubber does. Also the showing of the end of the wrap is not the same as what happened to Firestones (problems with cords/belts did not allow the tread to adhere during vulcanization). I have used tires with a fairly wide gap showing. It is up to you. I have seen it happen to more than one brand of tire.  Some tires are more prone to it than others. The wrapping of the tire is determined by the rotstion direction of the tire. The first time you see it, it can be quite un-nerving. Virtually every kart tire I used (spec tire class) showed the end of the wrap, some worse than others.

The end of the wrap showing is not the same as cutting a tire with a knife.

Nonetheless, you would race with a tire that has a gash in it, then its your decision. Just because the synptom is common doesn't necessarily mean the cause is the same. If we are all to presume all is ok, I wouldn't safety wire my bike because the nut should be able to stay on the bike... being cautious saves lives, and if one brand of tire tend to causes more concern, I probably not going to use it.