RCinNC
Well-Known Member
I've been a long time advocate of the Shinko 705, which I've always found to be a good all around tire at a very economical price. I wanted to make the members aware of a recent issue I had, however, so they can factor that into their buying choices.
Back in April I bought a Shinko 705 front tire in size 110/80 R19 from Rocky Mountain ATV to replace the worn out one on the S10. Up to that point, I'd personally mounted six of the same tire on the bike with no issues. The front tires have always been run at 36 PSI.
While riding the bike with this new tire installed, I experienced a handlebar oscillation on deceleration, between 39 mph and 31 mph. The oscillation acted like a wave; mild at first, then building in intensity to about the midpoint between 39 mph and 31 mph, then tapering off until it disappeared around 31 mph. The oscillation was fairly severe at the midpoint; with my hands off the bars, the bars oscillated hard enough that I kept my hands close enough to them to to act as steering dampers just in case it went into tank slapper mode.
I did the usual stuff to address this oscillation: proper headset adjustment, fork alignment, wheel balance, runout, front wheel bearing conditions tire pressure. Nothing was out of spec. I returned the tire and ordered another 705. In the meanwhile, I put the old worn out 705 back on the bike, and the oscillation went away.
I got the new replacement and mounted and balanced it. Same handlebar oscillation occurred, in the same speed range. Once again, I did those same standard checks to try and isolate the problem, to no effect; the oscillation was still present. I borrowed an Anakee 3 from a friend and installed this one on the S10, and the oscillation disappeared. So, I returned the second Shinko 705 and got a Bridgestone Battlax A41. There was no oscillation with the A41.
The first replacement Shinko 705 was made during the 17th week of 2022. The second was made during the 2nd week of 2023. My bonehead math says that's 37 weeks in between the production of those two tires with the same issue, which makes me think it's a persistent problem and not a one-off. The original worn out 705 that didn't have the issue was made in the 47th week of 2020. Could be a pandemic related quality control issue, but that's speculation on my part.
I can't say enough good things about the retailer I bought the tires from, Rocky Mountain ATV. I got no grief from them about returning the tires, and they made it a pretty easy process. I can't say the same about the customer service from ShinkoUSA. I emailed them about this 18 days ago and informed them of my experience, and the possibly of a defect in that production range. I haven't heard anything back from them.
I'm not going to do the internet thing and overhype this like Chicken Little on steroids. I could feel the weird sensation in the handlebars when I rode, which is what caused me to take my hands off the bars in the first place to see how the bike acted, but i wouldn't characterize it as an imminent danger unless you rode no hands. It's still a defect, though, and I have no idea if it would have gotten worse as the tire wore down.
I just wanted to put this info out there in case some of you were shopping for new tires. It did cause me to lose some confidence in Shinko; I ordered a set of Mitas E07's to replace the A41 front and Shinko 705 rear that are currently on the bike.
Back in April I bought a Shinko 705 front tire in size 110/80 R19 from Rocky Mountain ATV to replace the worn out one on the S10. Up to that point, I'd personally mounted six of the same tire on the bike with no issues. The front tires have always been run at 36 PSI.
While riding the bike with this new tire installed, I experienced a handlebar oscillation on deceleration, between 39 mph and 31 mph. The oscillation acted like a wave; mild at first, then building in intensity to about the midpoint between 39 mph and 31 mph, then tapering off until it disappeared around 31 mph. The oscillation was fairly severe at the midpoint; with my hands off the bars, the bars oscillated hard enough that I kept my hands close enough to them to to act as steering dampers just in case it went into tank slapper mode.
I did the usual stuff to address this oscillation: proper headset adjustment, fork alignment, wheel balance, runout, front wheel bearing conditions tire pressure. Nothing was out of spec. I returned the tire and ordered another 705. In the meanwhile, I put the old worn out 705 back on the bike, and the oscillation went away.
I got the new replacement and mounted and balanced it. Same handlebar oscillation occurred, in the same speed range. Once again, I did those same standard checks to try and isolate the problem, to no effect; the oscillation was still present. I borrowed an Anakee 3 from a friend and installed this one on the S10, and the oscillation disappeared. So, I returned the second Shinko 705 and got a Bridgestone Battlax A41. There was no oscillation with the A41.
The first replacement Shinko 705 was made during the 17th week of 2022. The second was made during the 2nd week of 2023. My bonehead math says that's 37 weeks in between the production of those two tires with the same issue, which makes me think it's a persistent problem and not a one-off. The original worn out 705 that didn't have the issue was made in the 47th week of 2020. Could be a pandemic related quality control issue, but that's speculation on my part.
I can't say enough good things about the retailer I bought the tires from, Rocky Mountain ATV. I got no grief from them about returning the tires, and they made it a pretty easy process. I can't say the same about the customer service from ShinkoUSA. I emailed them about this 18 days ago and informed them of my experience, and the possibly of a defect in that production range. I haven't heard anything back from them.
I'm not going to do the internet thing and overhype this like Chicken Little on steroids. I could feel the weird sensation in the handlebars when I rode, which is what caused me to take my hands off the bars in the first place to see how the bike acted, but i wouldn't characterize it as an imminent danger unless you rode no hands. It's still a defect, though, and I have no idea if it would have gotten worse as the tire wore down.
I just wanted to put this info out there in case some of you were shopping for new tires. It did cause me to lose some confidence in Shinko; I ordered a set of Mitas E07's to replace the A41 front and Shinko 705 rear that are currently on the bike.
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