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Thread: Z6 cupping

  1. #1
    STAN
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    Unhappy Z6 cupping

    I have only 1700 miles on my R1200Rt. I have always kept a close eye on tire pressure. About 200 miles ago I started hearing tire noise while in turns. Sounded just like when my old Avons would start cupping around 6kmi. After CLOSE examination yesterday I see that my front Metzeler Z6 is starting to cup. This is a real disappointment. Has anyone had a similar problem, or does anyone have any comments? These are my first set of Metzs and will probably be my last. I'm leaving Monday the 17th for what will probably be a 3000+k trip. I have a feeling the tires (or at least the front one) will be scrap when I get back. The rear tire still looks great.
    The fact these tires have absolutely no tread in the center of the tire does make me wonder about rainy conditions, but they have yet to be a problem in that department.

  2. #2
    DanGreene
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    Try running 38-40 in the front. This will probably help. With all the big advantages of the telelever front end, this may be one disadvantage.

  3. #3
    Rally Rat RTRandy's Avatar
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    I'm on my third set of Z6's and have gotten close to 8k before changing them each time. The reason I've changed them without letting them run longer is each time I was setting out on a trip over 5,000 miles and wanted to leave home with new rubber. The front tire has had cupping, but only towards the end of the life and certainly not at 1700 miles. My 04 RT is heavier than a 1200RT and I've always run 40 front and 42 rear.

    I've had a number of days caught in rain and give them high marks on wet pavement though I never push it when the ground is wet.

    Is it possible you have a defective tire? It may be worth contacting Metzler just to see what they have to say.

  4. #4
    Riding Dutchman jacco's Avatar
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    I changed my first front Z6 after 12k miles a month ago. I keep pressure between 37 and 40 psi. My rear Z6 has close to 8k on it now. It seems like it can do another 2k or so, maybe, although it's getting pretty flat in the middle... The rear I try to keep between 40 and 42 psi. This on an R1100R.

    A question about this rear Z6: Since there are no grooves in the middle, how do I know when the tire should be replaced? I did a lot of highway riding on this one, so there's plenty of thread left on the sides. Anyone with a suggestion? I don't want to ride until the carcas shows, but don't want to trash it too early either...
    Jacco
    2000 R1100R
    2003 F650CS

  5. #5
    DanGreene
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    There are wear marks on the rear Z6. You have to look very closely to see them. There are three, I believe, bumps in the tread groove. Not sure how helpful they are but they are there.

  6. #6
    Riding Dutchman jacco's Avatar
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    Quote Originally Posted by DanGreene
    There are wear marks on the rear Z6. You have to look very closely to see them. There are three, I believe, bumps in the tread groove. Not sure how helpful they are but they are there.
    OK, thanks! I'll look more carefully...
    Jacco
    2000 R1100R
    2003 F650CS

  7. #7
    Rally Rat torags's Avatar
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    Quote Originally Posted by jacco
    I changed my first front Z6 after 12k miles a month ago. I keep pressure between 37 and 40 psi. My rear Z6 has close to 8k on it now. It seems like it can do another 2k or so, maybe, although it's getting pretty flat in the middle... The rear I try to keep between 40 and 42 psi. This on an R1100R.

    A question about this rear Z6: Since there are no grooves in the middle, how do I know when the tire should be replaced? I did a lot of highway riding on this one, so there's plenty of thread left on the sides. Anyone with a suggestion? I don't want to ride until the carcas shows, but don't want to trash it too early either...
    I've wondered about that non groove riding surface in the middle. Where does the water go without the grooves? I suspect acqua planing may be a problem. That said, I've put 2 four hour high speed rain trips - with the only problem being underwear laundering.

  8. #8
    Rally Rat Grey_Matter's Avatar
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    What causes cupping?

  9. #9
    Rally Rat torags's Avatar
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    With cars its lateral wear points (excepting long storage flat spot). I wonder how a bike front wheel can get cupped also.

  10. #10
    Still Wondering mika's Avatar
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    I believe it is under inflation at some point that is long enough to set a wear pattern. The ridder may increase the preasurer in an effort to prolong the life but the cupping wear pattern remains and continues throught the life of that particular tire.

    Others may be able to confrim or correct this.

  11. #11
    ABC,AMA(LIFE),MOA,RA,IBMW MANICMECHANIC's Avatar
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    To find the location of the wear bars, look on the sidewall just next to where the tread begins. You should find some small triangles. At that location, in the tread grooves, will be the tread wear indicator.
    F.O.G.Rider, Rounder #6,
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  12. #12
    Riding Dutchman jacco's Avatar
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    Quote Originally Posted by manicmechanic
    To find the location of the wear bars, look on the sidewall just next to where the tread begins. You should find some small triangles. At that location, in the tread grooves, will be the tread wear indicator.

    Cool, thanks!
    Jacco
    2000 R1100R
    2003 F650CS

  13. #13
    Slowpoke & Proud of It! BRADFORDBENN's Avatar
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    I run 42 front and back on my 02 RT and I have gotten 8K out of Z6's I am at 12K on ME880's.
    -=Brad

    It isn't what you ride, it is if you ride

  14. #14
    STAN
    Guest
    Well, I'll up the front tire pressure from 36 to 40. I know when cupping starts it tends to get expotentialy worse with miles and there is no turning back. The good news is that they have barely just started to cup. I was alerted by the sound it was making. I'm suprised I could hear it at such a minor stage. No perceptable vibration yet. Hopefully the increased pressure will pull my fat out of the fire.
    I have over 25 vehicles on my insurance list, including several 18 wheelers so I cannot tell you how many tires I have on the ground. I have a lot of tire experience. Cupping is a problem that can show up on trailer tires (especially lowbeds with elementary suspension systems) and I think it is usually started by an out of balance tire. As the cupping develops the tire gets even more out of balance and the problem gets worse fast.
    My Kawasaki Concours hadcupping problems but usually around 6k. My R1100rt would start around 8k, but by then the tire was toast anyways. Thanks for all the insight, I'll be raiseing the pressure today.

  15. #15
    Rich Pelton Rich's Avatar
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    Quote Originally Posted by M1ka
    I believe it is under inflation at some point that is long enough to set a wear pattern. The ridder may increase the preasurer in an effort to prolong the life but the cupping wear pattern remains and continues throught the life of that particular tire.

    Others may be able to confrim or correct this.
    My front Z6 has never been underinflated, I keep an eye on the pressure religiously. I run 40-42 lbs and at 7000 miles the front tire is starting to cup also. But not near as bad as the Dunlop I had previous to this tire.

    I think I would blame the heavy weight of the bike on the cupping. But I really don't know either. I just know I've seen a ton of cupping tires on the front of RT's.

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