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Discussion Starter #1
Anyone ever seen this? It's missing chunks all around my front tire. They only have a little over 2k miles on them, and I bought them in January. They are Shinko 777 tires.
 

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Yep, bad tire. Happens to best of them at some point. Actually the first Shinko I've seen with a problem. Need to replace that, I wouldn't ride on it. It's giving you a warning.
 

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Iceshot, that's a solid deal, but I think this should be covered under some kinda warranty. Guess it'll depend on where you bought the tire from
 

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Discussion Starter #5

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Discussion Starter #6
Should I go with a different brand of tire? Outside of this event, I have been happy with how this tire feels.

Is there anything I might have done to cause this? I noticed that this happened right after my 400-mile trip. In that trip, was a sustained run of about 30 minutes above 90 mile an hour, with spurts to 110. Prior to this trip, I had gone out for a joyride, and ended up on a gravel road doing about 25. The tire speed rating is at least 130.

My coworker said that this brand is terrible and should be avoided, so I don't want to replace it with another one that will do the same thing or fail catastrophically!

What would you do if you were me? Would you take a free replacement, or a refund and buy different brand? Do I need to worry about my rear tire?

And of course, the weather is going to be nice next several days while I get this sorted out...
 

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It's all anecdotal, but I have had Shinko's on mine for a couple years, no issues. Tread depth is good with about 7000+ miles on them. The rear even has a plug in it (not recommended by the manufacturer or anyone else, but I check that it's holding air before every ride, and it's holding.)

Hopefully it's a QA issue, 110 shouldn't hurt a tire. I wonder what the production date code says? Maybe it was sitting on a shelf for too long and has dryrotted some? Definitely worth hashing out with Shinko/whoever you bought the tire thru.
 

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Has the tire always held air, or have you found it to be quite a bit low at different times?


Found this at Napa:
3 Tire Damage Warning Signs That It's Time to Replace Your RubberNAPA Know How Blog

I've seen this most often on large truck tires, those trucks never see autocross as mentioned below. Bad shocks? I don't think many companies replace shocks on their trucks :( But searching the term 'tire chunking' shows it happens somewhat often, even to the top brands.

1. Chunking

Chunking is the term used to describe missing sections of tread from a tire. It almost looks as though the tread has been sliced or torn off in chunks from seemingly random areas.

Tire damage like this typically occurs for one of two reasons. The first is related to suspension problems, such as a bad shock absorber making it impossible for the tire to maintain constant contact with the road. As it bounces up and down on the pavement, the force of the impact can cause tread chunking. A second common cause of chunking is related to heat — specifically, not warming up a tire before subjecting it to severe stress on an autocross or road course.

Chunked tires are not immediately dangerous, but their lifespan has been significantly shortened. The more tread that’s missing, the less grip they’ll have on the asphalt, which in turn can lead to unpredictable behavior under braking, in inclement weather or when cornering.
 

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Discussion Starter #9
The date code is 2618, so about June-July 2018.

Has the tire always held air, or have you found it to be quite a bit low at different times?


Found this at Napa:
3 Tire Damage Warning Signs That It's Time to Replace Your RubberNAPA Know How Blog

I've seen this most often on large truck tires, those trucks never see autocross as mentioned below. Bad shocks? I don't think many companies replace shocks on their trucks :( But searching the term 'tire chunking' shows it happens somewhat often, even to the top brands.
The tire was down two PSI from when I had it mounted in April, so it holds air well.

From the Napa article:
"making it impossible for the tire to maintain constant contact with the road. As it bounces up and down on the pavement, the force of the impact can cause tread chunking."

This made me pause. During parts of my return trip, I wanted to stretch my legs, so I slide up to the passenger seat and used the passenger pegs while riding. I kept my hands on the bars of course. This reduced the weight on the front tire, though it didn't change the stability feel of the bike. I didn't do this during corners, only straights, and when I knew I'd be at a steady speed. I never had to brake while riding like this.

Could the reduced weight on the front have caused the tire to momentarily lose contact and cause the chunking? It certainly never felt like it lost contact. I would think I would feel it lose contact.
 

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I don't think sitting on the back caused this. I've done that, and it does feel strange in the turns. Edit: Well maybe. Did the front shake any that you noticed?

Any irregular road surfaces around you? Like bridges with an open grid deck (see through), railroad tracks, unusual pavement, or cut pavement (traction cuts)? Hitting rumble strips can eat up tires pretty much like yours, doesn't take much for a semi to ruin a tire on them.

Are those spots all around the tire like that in a line? Those in the pic seem to line right up with the mold seams.
 

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Maybe you got a stone in your fender on that section of gravel road you were talking about..

Sent from my A502DL using Tapatalk
 

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Discussion Starter #12
Any irregular road surfaces around you?
I live in Illinois. We don't believe in paving roads until there is more potholes than smooth areas! :grin2:

But seriously, not really. One road on my commute is a "rough grooved surface" being prepped for repaving. However, I rode over this many many times without any issue. Probably 5 miles each way for 10-15 commutes. I checked my tire just before my 400 mile trip and it was clear of issues. That includes the gravel road just a few days prior to my trip. These spots only showed up after my trip, and there wasn't anything unusual about the roads we were on. The only difference from my normal riding is sustained high (90+) speed.

I aired up my tire to the recommended PSI by Kawasaki just before the trip.

The spots are all in a line, symmetrical to the center of the tire. I only checked half the tire, and it was consistent on that half. I assume it's consistent all the way around.

When riding in the passenger seat, I didn't notice any change to how it rode. No shaking or floating feeling.

The retailer wants another day to evaluate the warranty...than 3 days shipping...then an appointment to mount the tire. :doh:
Why can't it rain THIS week?
 

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Every manufacturing process for just about everything imaginable pops a lemon out every so often. I like Shenko tires. I use the 230 Tour Masters on mine and I've never had an issue. Shenko is a Japanese owned company that manufactures in South Korea.

I've heard a few sportbike people complain about them and perhaps that's not the best usage for them but for the 750 Vulcan they're fine.

More than likely, yours is that once-in-a-blue-moon lemon.
 
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