Anyone experienced Conti 25mm GP4000s II tire wall failure?

Anonymous

There was a bad batch I know for certain. A friend of mine bought 2 new from Decathlon and both had sidewall holes (rips) develop. Conti changed them for free and gave him free load of innertubes as a good will gesture. They acknowledged they were faulty.

earth

If you read around you will find many accounts of failing sidewalls with GP4000s. People loosing their front teeth, broken hips - you can die from that. Some of these may be brake pad alignment but the frequency is too high to account for all the failures. When I had a pair I found after about 500 miles threads started to come away from the sidewall just above the bead. I used to cut them off to stop them getting wrapped around the hub. I wouldn't go near a pair now not just because of the punctures every 10 miles.

redvision

earth wrote:

I wouldn't go near a pair now not just because of the punctures every 10 miles.

If you were having punctures every 10miles then either the tyre was very worn or at the wrong pressure.

earth

redvision wrote:

earth wrote:

I wouldn't go near a pair now not just because of the punctures every 10 miles.

If you were having punctures every 10miles then either the tyre was very worn or at the wrong pressure.

Tyres were brand new. I got a puncture within 10 miles of the first outing. I put between 100 and 110 psi in them. I continued to get punctures every 10 miles (total of 4 times) until I lined them with Kevlar tape, then the punctures stopped. I took them off about 500 miles later when the fibres started coming away from the sidewall. Later I put them back on another bike temporarily but removed the tape from one and again I had a puncture within 10 miles.

fenix

I've done 1000's of miles on mine with no problem. They're good tyres. People crash all of the time - GP4000s must be one of the most popular tyres out there - so stands to reason they'll have their fair share of incidents. And if its your brakes catching on the tyre - well that's schoolboy error.

What were causing your punctures ?

earth

Fenix wrote:

I've done 1000's of miles on mine with no problem. They're good tyres. People crash all of the time - GP4000s must be one of the most popular tyres out there - so stands to reason they'll have their fair share of incidents. And if its your brakes catching on the tyre - well that's schoolboy error.

What were causing your punctures ?

Two of them were shards of glass the others were unknown. But I switched to Michelin's and got 1000 miles between punctures. Now I use Veloflex tubs and my front tyre has had one puncture in 3000 miles and looks almost new, not even tread wear. The rear has been changed due to wear and a couple of punctures but I'm still impressed with the lifespan.

fenix

The world of the P******e is a weird thing.

Conti GP4000s = years with no bother.

Conti GP4000s tubs - flatted two on one 60 miler.

earth

Fenix wrote:

The world of the P******e is a weird thing.

Conti GP4000s = years with no bother.

Conti GP4000s tubs - flatted two on one 60 miler.

Real world experience always suggests bad luck and leaves me wanting some quantifiable measurement but when I have them consistently within 10 miles of going out and never experience that again with any other tyre then I have to think of the tyre as the culprit.

There do seem to be just as many people who have no trouble with them as those that do. Perhaps quality control is the issue. But have you ever noticed how many adverts for bikes have continental tyres on them? If bike radar do a tyre group test then the title photo for the article is always a continental tyre or a graphic of one. I suspect a large proportion of the price goes straight to the marketing department rather than the manufacturing process, which is unnecessary because a good product sells itself.

fenix

I see you said glass was the culprit twice - and the others were unknown. I don't believe there is such a thing. You need to ID the puncture and find it in the tyre/wheel. If you don't - then its still there and I think that's why you got so many ?

I have seen a European mag do a proper test of tyres - loads of data - resistance, grip, punctures = and the GP4000s romped home. They're bloody good tyres. I'd think you only hear of the people who have problems. The ones that are happy aren't going to join a forum to tell you this,

homers_double

Just reading through this thread as I've got GP4000's and after a weekend fettle noticed the same problem with my brake block as the OP however there is no way to lower the block in the caliper as it's already sat at the bottom of the slot.

Bike is an Allez, calipers are 105, wheels are Fulcrum racing 5 if anyone has any thoughts?

fenix

Are your wheels in properly ? Loosen the QR and bang it down ?

earth

Fenix wrote:

I see you said glass was the culprit twice - and the others were unknown. I don't believe there is such a thing. You need to ID the puncture and find it in the tyre/wheel. If you don't - then its still there and I think that's why you got so many ?

I don't remember the order that the punctures happened now but once I found the pieces of glass that caused two of the punctures I removed those pieces. I do remember one was a thin sliver and the other was a rough lump. They were both removed when found so the next punctures must have been for a different reason. I don't think it is the case that they were all caused by the same object.

I have also seen test results for tyres where the testing process was to attack the tyres with screwdrivers, knitting needles, darning needles and such things. Well I don't run over screwdrivers, or nails etc. Those tests are not representative. But hey I still have a GP4000S that I could put on again and I'll see how far I get.

homers_double

Fenix wrote:

Are your wheels in properly ? Loosen the QR and bang it down ?

Yes, everything is good as I'm ok on the mechanicals. Had a fettle earlier and it would seem worn blocks are the issue, pull on the brakes and they arc in further and therefore upwards, if you get my meaning.

New pads and they're bang on centre. Another reason to go for discs...

Anonymous

Prhymeate wrote:

Here are a couple of photos of my brake pad positions. I'm not workshop minded so to speak, but to me the position of the blocks against the rim looks about right, however the wear of the pads looks like that could be what's causing the problems? I'm guessing I should move them down a few mm. Seems strange though as I don't remember changing the position and I've been riding the bike for about 18 months.

So yet another thread title slagging something off that is actually the fault of the OP :roll:

You don't have to be 'workshop minded' to clean your bike.
If you did that, not only should you have noticed the weird pad wear, but also you would not have been rubbing abrasive grime into the side of the tyre!

Other photos on this thread look like the rider has hit the sidewall on something.

I have trashed two Four Seasons and a Shwalble One tubeless from bad riding, bad judgement and bad luck, but I don't rush to the net/forums looking for someone else to blame!

bompington

Well, that may be true - but I have always been careful to keep the pads off the tyres, there's no visible wear, and I can tell you for a fact that I didn't hit anything when mine blew out - most of my riding is on roads that are filled with potholes, mud and stones so I'm pretty careful to look where I'm going.

For me, the real question is about the GP4000 specifically - there have been a lot of complaints about this happening: is the GP4000 worse than other tyres? Or is it confirmation bias - would I quickly attract tales of woe about another brand if I started a thread on that?
Until last Saturday I would have assumed the latter, now I'm not so sure.

fenix

As I've said before - its a really popular tyre. Probably the most popular ?

So you will get a few stories of disasters. Some the riders fault - misaligned blocks, over, under inflation etc etc.

I dont personally know of anyone having problems with them and I swear by them.

redvision

Fenix wrote:

As I've said before - its a really popular tyre. Probably the most popular ?

So you will get a few stories of disasters. Some the riders fault - misaligned blocks, over, under inflation etc etc.

I dont personally know of anyone having problems with them and I swear by them.

I agree. From my experience GP4000s are a fantastic, reliable tyre.

priory

I just noticed this thread
I got a pair of michelin endurance 25mm and put them on last year
200miles later the front popped when i hit a little sharp stone , 1cm cut on side-wall, exactly like the one on the second puncture at the start of the thread.
I put the rubinoes back on , cheap but I think they are more robust.

earth

The tell tale sign on this is going to be the adoption of disc brakes.

chrisw12

earth wrote:

The tell tale sign on this is going to be the adoption of disc brakes.

Just read this thread and was going to reply anyway but how ironic that this was the last post.

Been on Conti 25mm for years, great tyres, absolutely no probs, can’t remember having any punctures...

Bought a disc braked bike in March and bought some 28mm Conti (which to my pleasure came up at 30mm). The first one on the rear developed a hop, I couldn’t be bothered at the time to investigate properly, I’ve had years of installing tyres, never had this on a clincher so just put it down to bad luck. Bought another Conti in 28mm. Long story short. Coming down the Galibier two weeks ago and bang, tube gone. Didn’t have time to investigate and really wanted to catch back up with my ‘support car’ I put another tube in and within miles same again. Investigated when I got home and exactly the same type of cut as the original photo in this thread!

So be aware, this problem can be caused by brake rub, but no way in this case!

buckmulligan

It's worn in a groove around the edge of the rim like the first picture in this thread? Or just had a single-point failure just above the rim? Have you checked your rim bead for any burrs or sharp edges?

Tiesetrotter

From the years of riding in a group I can say Conti GP4000's do suffer from very occasional tyre wall failures. But it's at the end of their life. I ride Vittoria and they don't suffer that problem but they do cut up more quickly and have a shorter shelf life. There is compromise in everything.

I thought I was riding Vittoria's because they were more supple and faster. Hogwash according to this site:
http://www.bicyclerollingresistance.com ... ke-reviews

chrisw12

Groove like first pic, not a point failure as it was big enough for a butyl tube to poke through, then for an under inflated butyl tube to get through. When I got to my accommodation I was able to put my little finger through it at which point the tyre ripped so that I could have got my thumb through. At that point, I binned the tyre and got on the beers.

I’m not ruling out the rim itself but since I’ve put a new non Conti tyre on I won’t be checking anytime soon unless that goes pop as well. Rims are vision metrons 40s so not exactly cheap.

FWIW and given I’m not an expert and didn’t do much analysis, the failure came at the threads connecting the bead to the carcass.

Pressure before anyone ask, I’ve been inflating these to a max of 90 then letting them naturally deflate to about 70 before I reflate, there doesn’t seem to be much proper independent info on correct tyre pressure of 28mm tyres. I used to inflate 25s to 100 and as said never had a problem.

molteni_man

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?

molteni_man

Incidentally a tip I read on this forum to help prevent punctures was to deflate the tyres after rides and remove any flint/ stones in the tyres. The thinking being was that punctures were more likely caused by the penetration of these flints over a period of time. Deflating to protect the sidewalls allows me to check for these flints and prise them out easily.- you cannot see them always when the tyre is fully inflated or indeed remove them. I can't say I do this after every ride but did recently remove about 20 flints from my wife's bike after a really gravelly set of roads we rode which I'm sure would have led to a puncture.

apreading

But who can be ar*ed to deflate the tyres after every ride. Surely only someone who doesnt ride very much?

itboffin

Indeed

chrisw12

I’d also add to that, your tubes valves are going to be in for a hammering doing that. I’ve run latex tubes and the continual pumping up meant that the valves failed before I punctured..

molteni_man

I ride plenty. As I said it's something I'm trialling and shared. Not for everyone, but personally I like to check my tyres before each ride - and have never had any issues with valve failure.
Over the winter period when I use the winter bike only it will be even easier. It's a trial which I'll report back on. BW

svetty

Have to say that I used to always use GP4Ks but did find that eventually the side wall threads would start to come away and this - rather than wear down to the wear mark - was the reason I would replace them. I never had a sidewall failure however. I also used Ultremos and they would suffer the same fate.
I then had a spell using Vittoria Corsas which I thought were excellent but these are no longer available and I refuse to pay the money they are asking for the new graphene ones. Now I mostly use Veloflex clinchers which don't seem to be prone to problems but do wear the tread down faster than the Contis. Perhaps I should give the MIchelin Power Comps a try?

GP4S in winter (of course )