Why cracks in Conty GP 3000?

Quoted message said:

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim. About 2 years old and 200o
miles and never flatted. I inflate to 120# before EVERY ride. I weigh 185#.

To me, it looks like dry rot. Could you be storing your bike near a heat source when not being used?

I too ride GP3000 700x20c and I've never had a flat. Nice tires, IMO. I inflate to 150 lbs. per
square inch and I weigh 155 lbs. I wonder if the lower pressure you ride at is causing the damage?

If it matters, I also use the same color as you appear to.

Dave

onefred said:

Quoted message said:

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim. About 2 years old and 200o
miles and never flatted. I inflate to 120# before EVERY ride. I weigh 185#.

To me, it looks like dry rot. Could you be storing your bike near a heat source when not
being used?

My road bike is not stored near any heat or ozone sources, and my Conti's cracked just
like the OP's.

No other brand of tire I've used has had the problem. I have five bikes, and change tires based on
riding conditions on some of them, so I own a few tires. <G>

Barry

does the rim do the CRAB? that is, in relation to the vehicles general travel direction or is the
rim higher on one side than the udder. check your shoes!! I get cracks, puckers, rubber popouts,
loose strings, small round popouts of inner carcass materials... yech. I clean and smear with GOOP
and rotate.

Dry rot? Often the bike is on the bench rack just in front of the hot engine of the truck, Dave.
Other times, it's suspended over the minivan, but again over the engine-end. I suspect it does get
some heat, but the cracks appear on the side opposite the heat source... (puzzled look...)

John

onefred <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Quoted message said:

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim.

About

Quoted message said:

Quoted message said:

2 years old and 200o miles and never flatted. I inflate to 120# before

EVERY

Quoted message said:

Quoted message said:

ride. I weigh 185#.

To me, it looks like dry rot. Could you be storing your bike near a heat

source when not

Quoted message said:

being used?

I too ride GP3000 700x20c and I've never had a flat. Nice tires, IMO. I

inflate to 150

Quoted message said:

lbs. per square inch and I weigh 155 lbs. I wonder if the lower pressure

you ride at is

Quoted message said:

causing the damage?

If it matters, I also use the same color as you appear to.

Dave

I had the same problem (6 tires) and sent them back to Continental and they replaced them. The
problem was the tire got too hot in the mold and they failed prematurely. I used the replacement
tires and the same thing appeared on them and they are now folded up in my garage and I switched all
of my bikes (6 of them) to Michelins Pro Axial Carbons (700-25) and have had no additional problems.
I can make you a real good deal on 6 GP3000 with < 200 miles on them. ;-) FWIW, I dealt with
www.bikemine.com in OK as they are the stateside distributor in my area (DFW) for Continental. Prior
to this problem I had been a Continental user for 10+ years. Let us all know how you make out. "John
Crankshaw" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Have a look at these pix...

michiganjohn.home.att.nettire pix.htmOpen ↗

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim.

About

Quoted message said:

2 years old and 200o miles and never flatted. I inflate to 120# before

EVERY

Quoted message said:

ride. I weigh 185#.

I noticed today cracks in the tread in parallel to the rim and only on the left side. Lots of
cracks, but none of them apparently showing any cord.

In

Quoted message said:

the pix, it almost looks like tread wear -- looks worse live.

Why are these cracks appearing? Excepting the cracks, the tire looks good with lots of wear left.
Safe to ride?

John Crankshaw wrote

Quoted message said:

Quoted message said:

Have a look at these pix...

michiganjohn.home.att.nettire pix.htmOpen ↗

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim. About 2 years old and 200o
miles and never flatted. I inflate to 120# before EVERY ride. I weigh 185#.

An anonymous poster replied:

Quoted message said:

To me, it looks like dry rot.

No way. This is a common error. Dry rot mainly affects wood, and can also affect other
cellulose-based materials, but there's nothing in a modern tire that is vulnerable to this fungus.

One of the symptoms commonly confused with dry rot is ozone damage, which commonly causes a sort of
bubbling up, primarily on gum sidewalls.

The cracks shown in the link above are purely cosmetic, and nothing to be concerned about as long as
the tire is not lumpy or misshapen.

Likely has to do with the lack of carbon black in the colored tread, but that's just a guess
on my part.

Sheldon "No Wood In Bike Tires" Brown +----------------------------------------------------------+
| If only God would give me some clear sign! | Like making a large deposit in my name at a Swiss
| bank. | --Woody Allen |
+----------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 harriscyclery.comharriscyclery.comOpen ↗ Hard-to-find parts
shipped Worldwide captainbike.comcaptainbike.comOpen ↗ sheldonbrown.comsheldonbrown.comOpen ↗

(g.daniels) said:

I get cracks, puckers, rubber popouts, loose strings, small round popouts of inner carcass
materials

I used to get 'em too. Now I don't use Conti road tires, and the problem is gone. <G>

I especially hated those silly threads that kept coming out of the sidewalls. Conti off-road tires
don't seem to have the problems.

Barry

Barry, do you keep on ridin' the cracked Contis?

John

B a r r y B u r k e J r . <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

onefred said:

Quoted message said:

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim.

About

Quoted message said:

Quoted message said:

Quoted message said:

2 years old and 200o miles and never flatted. I inflate to 120# before

EVERY

Quoted message said:

Quoted message said:

Quoted message said:

ride. I weigh 185#.

To me, it looks like dry rot. Could you be storing your bike near a heat

source when not

Quoted message said:

Quoted message said:

being used?

My road bike is not stored near any heat or ozone sources, and my Conti's cracked just like
the OP's.

No other brand of tire I've used has had the problem. I have five bikes, and change tires based on
riding conditions on some of them, so I own a few tires. <G>

Barry

Hi Mr. Brown:

I guess I will have to pay closer attention to my GP3000's.

One thing in your post really caught my attention, though.

Quoted message said:

An anonymous poster replied:

Why do consider me to be an anonymous poster?

Dave

John Crankshaw said:

Barry, do you keep on ridin' the cracked Contis?

Some of them I did, but when the sidewall threads started to unwind, or the tread chunked, I'd toss
them. I'm a former big fan of GP3000's, but I had a lot of problems with them in 2001 and 2002.

I now ride Michelin Pro Race tires which have proven to be durable, long wearing, and nice riding.

I still use Conti mountain bike tires on some of my bikes with excellent results.

Barry

Quoted message said:

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim.

About

Quoted message said:

2 years old and 200o miles and never flatted. I inflate to 120# before

EVERY

Quoted message said:

ride. I weigh 185#.

For the 20c tire, and your weight, 120psi is definitely on the low side. I'd recommend going to the
full-rated pressure on the tire (I believe it's 150psi). If you want a smoother ride, switch to a
23c @ 120psi.

Quoted message said:

I noticed today cracks in the tread in parallel to the rim and only on the left side. Lots of
cracks, but none of them apparently showing any cord.

In

Quoted message said:

the pix, it almost looks like tread wear -- looks worse live.

Why are these cracks appearing? Excepting the cracks, the tire looks good with lots of wear left.
Safe to ride?

High-end Contis have had problems with cracking off-and-on for some time, although I haven't seen it
much lately. If it's just a few small surface cracks, it's no big deal, and on a rear tire,
virtually never a problem, since the cracks are age-related, and rear tires usually wear out before
the cracks are very big. Front tires can sometimes (if they're lucky) have a very long lifespan, so
such cracks are more likely to appear.

As long as the casing is undamaged it's not a problem, although as the cracks appear closer to the
top of the tread I become more concerned that road debris may choose to lodge in them. For a tire
that looks like the one in the photo, Conti will generally replace them without trouble. But for
those who are now running out to check their tires, if you find something like what's in the photo,
it's not something that should keep you from your next ride. [A lawyer, however, would caution me
to say that you shouldn't ride your bike if you notice *anything* out of the ordinary. Of course,
the lawyer might also want me to say that bikes aren't designed to be ridden on roads with cars or
other dangerous obstacles, and that doing so voids the warranty and may cause serious injury or
loss of life.]

--Mike-- Chain Reaction Bicycles chainreactionbicycles.comchainreactionbicycles.comOpen ↗

mrbubl said:

I had the same problem (6 tires) and sent them back to Continental and they replaced them.

I've had good luck with Conti tires - I found all you have to do is ride enough miles to wear them
out before they start decomposing.

End of problem... ;-)

Mark Hickey Habanero Cycles habcycles.comhabcycles.comOpen ↗ Home of the $695 ti frame

the tire wear "anomalies" - visual changes in the tire's structure over time and mileage possibley
increase with the tire's designed complexity. A simple tri-sport has a flexible carcass that goves
but doesn't give much upward in return for the rider. The DuroTour, an excellent bargain tire maybe
a world tire used in the shanghi commute does the same but over a longer distance/time and
effectively. And these two despite hi loads at 20+ sppeds never shed much. But the Conti TT and the
Spec Turbo's sides show stresses in the rubber carcass "covering" but no degradation of hadling
characteristics from the carcass proper. The Spec Turbo, not having a complex carcass like the Conti
TT or Aramidillo, and probably not meant for hi speed hi load touring/commuting with the wood stove
on the rack seperates the tread from the tire!! looks like a Bandag on a overloaded triax!! But the
apparent visual seperation never seperated much to my amazement nor did the performance degrade
under slaloms thru the airport lot with the stove and a rippin' good hind wind!!

onefred said:

Quoted message said:

An anonymous poster replied:

Why do consider me to be an anonymous poster?

Why is it common for people to take issue with the automatically generated credit lines?

I think we should all change our newsreaders to put "Somebody wrote:" rather than "<insert name
here> wrote:"

Then, no more issue with offending people by putting "anonymous", part of their name, or their name
combined with their email address to create a horrible monster.

Hibbity jibbity, a rat a tat tat!

Quoted message said:

Dave

--
Rick Onanian

"John Crankshaw" <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

Have a look at these pix...

michiganjohn.home.att.nettire pix.htmOpen ↗

This is a Continental GP3000 tire, size 20x700c on a Mavic CXP33 rim. About 2 years old and 200o
miles and never flatted. I inflate to 120# before EVERY ride. I weigh 185#.

I noticed today cracks in the tread in parallel to the rim and only on the left side. Lots of
cracks, but none of them apparently showing any cord. In the pix, it almost looks like tread wear
-- looks worse live.

Why are these cracks appearing? Excepting the cracks, the tire looks good with lots of wear left.
Safe to ride?

Dear John,

If the cracking is entirely on the left side, fairly regular, and on the more heavily weighted rear
tire, might it be the result of steady riding on the right-hand side of roads with a distinct crown?

That is, the left-hand side of the tire on such a road would flex slightly more than the right, even
at 120 psi. An identical front tire might not have enough weight on it to flex so much.

I have no data or experience to support this possibility, but either something acted on the
left-hand side during manufacture or else something acted on the left-hand side during your rides.

Carl Fogel