Anyone experienced Conti 25mm GP4000s II tire wall failure?

evil_breakfast

I bought some OEM from my LBS.
These have definitely done less than 1000 miles and I'm quite the lightweight @ 70kgs

As you can see, the 'shoulder' of the tire has the carcass fabric showing through :shock:
I'm not in the habit of checking my tires before/after every ride (save from a thumb to check pressure) so I was :shock: when I did a glass/flint check and saw this

akh

I've had the same pair of 25mm GP4000s IIs on my bike for around 4,000 miles and no sign of any issues with the sidewall. The tread has a few small nicks in places from the odd bit of glass. In that whole time I've had two punctures. One from glass all over the road (looked to be from a car crash) and one from a pinch puncture from hitting a pothole. I could be wrong, but I don't think there is any major design flaw in the tyre. I would guess there are hundreds of thousands or millions of these tyres being ridden around the world, so even if significantly under 1% fail, that's still a fair number in absolute terms. I'll be replacing mine with another set of the same.

philbar72

I had 23 /25 mm front/ rear on my hed jets and the Kevlar weave went on the rear. not sidewall....

ZMC888

Some of my local roads have small stones dropped by trucks or broken off cliffs on mountain roads (China). This has lead to two or three sidewall tears on different tires, incl 28mm and 25mm tires .

In the UK on my UK bike I hit a pothole on a small dirty green lane and this again caused a sidewall tear.

I weigh 80kg (approx 13 stone) and this has been two bikes and thousands of kms apart, so not freak accidents.

I have switched to GP 4 season, which seems much tougher and better for my conditions, however I wish they made a Conti 25mm GP4000s II with tougher sidewalls as I really miss the cornering and speed.

Orkneylad

I've also had a couple of pinch flats on the 23C GP4K-2, and a lot of scarring on the ride surface. Might be the poor road surfaces up here (not a lot of smooth tarmac). Switched to the GP4season and far superior so far.

molteni_man

Molteni Man wrote:

Hi all,
I run Conti 4000s too and have also had a couple of side walls go as described. I love the tyres and grip they provide and find they give great p******e protection too.
I'm trying something new which a friend suggested having been advised by a bike shop owner who hired out bikes and who swore by it as a means of prolonging tyre life. The suggestion was to drop / release the pressure after each ride rather than leave the tyres fully inflated. I'm now doing this but is probably too early to say whether this will help in the longer term as have only done this with the new tyres I fitted 2 months ago. Have had no issues to date and It's really no hassle so will persevere. Would be interested if anyone else has done this/ heard about it?

I thought I would update on this trial. Firstly, I can’t say that I have deflated tyres after every ride especially when riding in the summer. However, where I have done this mostly on my Tarmac which has had Conti GP 4000s on for a year I have had no sidewall issues. I have done the same on my wife’s bikes too and again no issues with sidewalls. Too small a trial to know definitively!
On a different note, I have run Pirelli P Zero Velos to compare against the Conti. The Pirellis are super comfortable giving a ‘softer’ ride than the 4000s. The Pirellis give great grip in the wet, better imo than the 4000s. I’m not sure that they give quite as much mileage.

Tiesetrotter

Quite a few of the guys I ride with have GP4000's, including me. They are good tyres. But we all occasionally get the sidewall issues.

Every tyre brand has some issue or other. I use Vittoria's and they tend to cut up way before they wear out. Conti' 4000's seem to have the odd sidewall issue.