Shinko tires

Discussion in 'Road Warriors' started by LuciferMutt, Jul 22, 2021.

  1. LuciferMutt

    LuciferMutt Rides slow bike slow

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    I needed new tires on my TU250. Being that it uses skinny, 18" retro sizes, the pickings are a bit slim, so I decided to take a chance on the Shinko 712 which seemed pretty highly regarded over on TU250riders.net. It helps that there were about $60/tire. This results in a 100/90/18 on the front instead of the stock 90/90/18 on the front, but the new tire fit without rubbing on anything, and supposedly corrects the cable-driven speedometer error with the slightly taller profile. I had a good local shop I give lots of business to order, mount and balance the tires for me. I brought them the wheels off the bike, and then carefully re-installed the wheels myself, as I have done for many years.

    I had my maiden ride on the new tires yesterday, and I'm getting a terrible bouncing from what seems to be mostly the front, basically everywhere between 35-60 mph -- IE pretty much the entire ride on backroads. It feels like I'm driving over low-frequency rippled pavement, and if I look down at the front wheel, I swear I can see the forks bouncing up and down. When I kind of stand on the pegs and look down at the front tire, the left side of it seems to be spinning pretty true, but then I look over at the right side, the edge of the sidewall (a nice reference to watch while it spins) appears to be non-concentric as it rotates, moving very obviously up and down in a frequency that seems to match my bouncing.

    Does this sound like I got a bad tire that isn't round? I mean, Shinkos are cheap, but this seems pretty egregious. When I got home I carefully inspected the bead area and the tire seems to be installed correctly, and I'm completely positive I mounted the wheels on the bike properly. I did notice that the shop had to use two big strips of balancing weights on both sides of the front wheel in the same spot.

    For a tire like the 712, is it even worth trying to see if there is anything that can be done, or should I chalk this whole thing to an expensive learning experience and get a better quality tire on the front and be done with it? Pretty disappointed...I've never had a problem with a new tire like this before.

    The rear tire didn't seem to do anything weird. On googling, I'm finding pretty varied reports of people have similar problems with the FRONT 712....poor QC?
    #1
  2. AwDang

    AwDang Enabler

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    I’ve put 712’s on an R65 and Street Twin, none of what you describe. I’d call it a bad tire and try to get it warrantied.
    #2
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  3. sanjoh

    sanjoh Purveyor of Light

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    I had a similar experience with a T63 michelin. Bead looked normal, tire looked normal, turned out it was not seated. 21" tube type tire on an airhead. Took 100psi and a couple hours in the sun to get the bead to seat.
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  4. ivantheterrible

    ivantheterrible Long timer Supporter

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    I had exactly the problem you describe and it was from the bead not being completely set. It almost was, and that was the problem, I thought it was but on closer inspection realized it was just a little off. More air and it Changed it from a scary, wtf situation to smooth as it was supposed to be.
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  5. anotherguy

    anotherguy Long timer

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    Sounds like an out of round tire. If you want you could give it a try for a replacement.

    Seen way too many poor results to recommend those jelly donuts to anyone. Quite the opposite in fact. Avoid at all costs. Buy a used tire first. Yep that bad.

    Now all the guys whose luck has been good will crawl from under that cheap ass rock they live under. :D
    #5
  6. Dao1

    Dao1 Long timer

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    Can't say one way or the other re: your tire problem... but....
    imo, if i had to go cheap, i'd rather go w/ a shinko brand vs. lesser ones (eg, tusk, magnum tires)
    #6
  7. cyclopathic

    cyclopathic Long timer

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    Was tire seated and balanced properly? Lift bike and rotate front wheel to see if it is smooth or wobbly. Most likely:
    1) tire wasn't beaded correctly
    2) isn't balanced;
    3) defective tire.

    There's also a possibility that you have loose/worn wheel bearings

    As for #1 I had seen it happen pretty big hump just because bead wasn't positioned equally an tire was a tight fit on rim. If it is defective tire get it warranted by Shinko good luck.
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  8. LuciferMutt

    LuciferMutt Rides slow bike slow

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    I'll put the front on a stand when I get home to check, but I'm fairly certain the tire is seated and installed correctly. How can I tell if a bead is not seated just by looking at it?

    The wheel bearings and head bearings, etc are all fine. The old tire did none of these things, the bike only has 5K miles on it, and I checked the bearings when I had the wheel off.
    #8
  9. VicRattlehead

    VicRattlehead Been here awhile

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    I can't believe any respectable tire shop would balance a tire that was defective, out of round or not seated properly, which sounds like what happened here. It should have been glaringly obvious the second they put it on a balancing stand/machine. "2 big strips of weights in the same spot" should have been their first clue that something was up. Any more than 1oz., 1.5oz. TOPS and I start looking for issues with the tire or I try remounting.

    That being said, it is possible you got a bum tire, though I would suspect that its not fully seated on that one side.
    As to Shinko, I've used a LOT of their tires on numerous bikes and never once had a QC issue. In fact, my current Sportster is running on a set now and other than wearing faster than I'd like, they've been great.
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  10. Wa Ho Thuk

    Wa Ho Thuk Long timer

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    It could be from any number of things . I have been running nothing but Shinko tyres for years now on big Guzzis with zero issues . Mostly the 712 , a couple of 230 models , all have been fine , and out here in the middle speed limits are merely a suggestion . Oddly enough , a mate with a newish Bonneville is having the same problem as you are with a new high dollar Michelin , go figure .
    #10
  11. ivantheterrible

    ivantheterrible Long timer Supporter

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    there's a raised rubber line that goes around the tire and is about a 1/4 inch from the edge of the rim when the tire is seated properly. Mine was fine all the way around but then dipped about and 1/8 of an inch closer to the rim in a 8 to 10 inch section and that was enough to cause the bouncing.

    All of this was about 6 or 7 years ago so some of the details might be off but I affirm that this is basically accurate to the best of my memory.
    #11
  12. cyclopathic

    cyclopathic Long timer

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    When I had that happen it was pretty obvious, there was a 1" hump tire was out of round. Breaking bead and resitting fixed it.

    I'd expect tire being out of round or balance should have been caught during install by competent tech
    #12
  13. anotherguy

    anotherguy Long timer

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    One of the drawbacks of taking wheels in off the bike. No road test after mounting. Some shops refuse that kind of work.
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  14. Blackshirt

    Blackshirt Long timer

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    Sounds like it is not fully seated or that someone hamfisted the tire removal/install and messed up the rim’s runout. It happens, but it’s easy to check and fixable. Look at a particular point on a fender stay or fork and watch for a bit of the rim that sticks out further than the rest. I fixed this problem by sending my rim to Woody’s in Denver to be straightened. More commonly, it is a poorly seated tire or a lost wheel weight.

    I have been very pleased with Shinko tires. I do my own tire mounting, so these super-affordable-yet-excellent tires make riding an affordable proposition without sacrificing much over pricier offerings.
    #14
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  15. LuciferMutt

    LuciferMutt Rides slow bike slow

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    Took a quick look yesterday, and will investigate much more thoroughly today -- but now I'm pretty sure you guys are right and the bead is not seated. I followed that reference line around the wheel rim, and there's a section about 3-4" long where it's not concentric with the rim anymore (it moves farther away from the rim).

    Deflate the tire, squirt some lube at the tire/rim interface, whack it with a rubber mallet and reinflate to 50+ PSI?

    Do I need to take the wheel off the bike again just to try this (I'll put it in the air).

    Worse case scenario I can always take the wheel back to the shop and show them.
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  16. Dno

    Dno Been here awhile

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    Put that sucker in the sun and reinflate with some tire lube. Bead might not be set. Ive had to over pressure quite a few. Then static balance with solder on the spokes. Sun helps alot to get bead set. The tire needs to be hot. And more pressure than I want to say. Best with locking tire chuck and distance. I have done 50 psi after wd40 around bead and just left in the sun to come back to a set bead
    #16
  17. racer1735

    racer1735 Long timer

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    Shinko are an inexpensive but quality tire. The company has been making tires for over 50 years and got into the motorcycle tire field in the ‘80s when they took over Yokohama tires. You may have a bad tire (that happens) but I’d try the above mentioned methods of getting the thing seated and in-round first.
    #17
  18. Richy

    Richy Long timer

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    I’ve used them a couple times. The only problem I’ve had was seating the bead on one, a rear 16”. Made me wish I had a cage, I put so much air in it.
    #18
  19. VicRattlehead

    VicRattlehead Been here awhile

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    Once you get the bead seated be aware that it will now be horribly out of balance.
    #19
  20. Blackshirt

    Blackshirt Long timer

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    I’ve added the cleaning and waxing of inner rim shoulders to my tire changing regimen. It makes it easier to manipulate the beads into the trough of the rim while mounting the tire and the beads will seat more easily.
    #20
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