Grand Prix 3000 problem?

[Mark Heiple]

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.

 

[Dianne_1234]

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.

 

[Mrbubl]

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.