Grand Prix 3000 problem?

Discussion in 'Cycling Equipment' started by Mark Heiple, Aug 23, 2003.

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  1. Mark Heiple

    Mark Heiple Guest

    I have been riding on a set of GP 3000 (700 x 25), inflated to 120 psi for about 350 miles now and
    it looks like I might have a defect in the casing (both tires).

    About one third from the edge of the thread on one side, I can see a ridge or seam developing. The
    ridge isn't on the other side. I took the tires off the rim and looked at the inside of the tire,
    but I didn't see any broken threads.

    However, I did see an interesting pattern in the threads. Under the tread, the threads appeared to
    run diagonally across the tire (which I expected). Towards the bead (under the sidewall) the cord
    pattern seemed change to run perpendicular across the tire. The border where the change occurred
    appears to be exactly where I'm seeing the ridge in the tread.

    I'm wondering if I'm seeing an edge of the anti-puncture layers, and they aren't centered under the
    tread like they should be. It also looks like there is some stretching in the casing in a few places
    at the border.

    Other than this, there aren't any bulges in the sidewall, obvious broken/cut threads, but I'm
    worried that I'm risking having the tires split on me.

    My previous tire was a GP 3000 (23mm), and had no problems. I decided to try the wider size because
    I'm big, and I've read a lot that the wider tire rolls better. Hard to tell, but I think it might be
    true. I'm not any slower at least.

    Thanks.
     
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  2. Dianne_1234

    Dianne_1234 Guest

    Mark Heiple <[email protected]> wrote in message
    news:<[email protected]>...
    > I have been riding on a set of GP 3000 (700 x 25), inflated to 120 psi for about 350 miles now and
    > it looks like I might have a defect in the casing (both tires).
    >
    > About one third from the edge of the thread on one side, I can see a ridge or seam developing. The
    > ridge isn't on the other side. I took the tires off the rim and looked at the inside of the tire,
    > but I didn't see any broken threads.
    >
    > However, I did see an interesting pattern in the threads. Under the tread, the threads appeared to
    > run diagonally across the tire (which I expected). Towards the bead (under the sidewall) the cord
    > pattern seemed change to run perpendicular across the tire. The border where the change occurred
    > appears to be exactly where I'm seeing the ridge in the tread.
    >
    > I'm wondering if I'm seeing an edge of the anti-puncture layers, and they aren't centered under
    > the tread like they should be. It also looks like there is some stretching in the casing in a few
    > places at the border.
    >
    > Other than this, there aren't any bulges in the sidewall, obvious broken/cut threads, but I'm
    > worried that I'm risking having the tires split on me.
    >
    > My previous tire was a GP 3000 (23mm), and had no problems. I decided to try the wider size
    > because I'm big, and I've read a lot that the wider tire rolls better. Hard to tell, but I think
    > it might be true. I'm not any slower at least.
    >
    > Thanks.

    Your analysis fits with what I've seen.

    I just cut open a dead Conti GP 3000, and the anti-puncture belt appears to be as thick as (or
    thicker than) any other ply. It's also the first ply below the tread rubber, so your cracks in the
    tread don't surprise. The belt is off-center on the tire I sectioned, and if it's off-center in your
    tires that might explain why you see cracks first on one side only.
     
  3. Mrbubl

    Mrbubl Guest

    I have seen the same thing on 4 pairs that I had of the GP and they were replaced by Conti and the
    new ones did the same thing, then I went to Michelins. $45 a tire x 4 pairs is too much money to
    have wasted away IMO. I am sure that if I sent them back again, they would replace them AGAIN but to
    date they are sitting in the garage till I decide what to do. BTW, I am happy with the Michelins
    other than they don't have any noticable tread.

    I was told that the problem was a heat issues with the mold @ the factory but I wonder when it was
    found, how many tires are out there and if they are only replaced as needed or complaints made.
    700-25 seems to be a harder size to find in variety.

    Bike Mine www.bikemine.com is where I sent mine for replacement recommended by Continental if that
    helps. "dianne_1234" <[email protected]> wrote in message
    news:[email protected]...
    > Mark Heiple <[email protected]> wrote in message
    news:<[email protected]>...
    > > I have been riding on a set of GP 3000 (700 x 25), inflated to 120 psi for about 350 miles now
    > > and it looks like I might have a defect in the casing (both tires).
    > >
    > > About one third from the edge of the thread on one side, I can see a ridge or seam developing.
    > > The ridge isn't on the other side. I took the tires off the rim and looked at the inside of the
    > > tire, but I didn't see any broken threads.
    > >
    > > However, I did see an interesting pattern in the threads. Under the tread, the threads appeared
    > > to run diagonally across the tire (which I expected). Towards the bead (under the sidewall) the
    > > cord pattern seemed change to run perpendicular across the tire. The border where the change
    > > occurred appears to be exactly where I'm seeing the ridge in the tread.
    > >
    > > I'm wondering if I'm seeing an edge of the anti-puncture layers, and they aren't centered under
    > > the tread like they should be. It also looks like there is some stretching in the casing in a
    > > few places at the border.
    > >
    > > Other than this, there aren't any bulges in the sidewall, obvious broken/cut threads, but I'm
    > > worried that I'm risking having the tires split on me.
    > >
    > > My previous tire was a GP 3000 (23mm), and had no problems. I decided to try the wider size
    > > because I'm big, and I've read a lot that the wider tire rolls better. Hard to tell, but I think
    > > it might be true. I'm not any slower at least.
    > >
    > > Thanks.
    >
    > Your analysis fits with what I've seen.
    >
    > I just cut open a dead Conti GP 3000, and the anti-puncture belt appears to be as thick as (or
    > thicker than) any other ply. It's also the first ply below the tread rubber, so your cracks in the
    > tread don't surprise. The belt is off-center on the tire I sectioned, and if it's off-center in
    > your tires that might explain why you see cracks first on one side only.
     
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