Conti GP 4000S 11 "Review"

Wold Ranger

Old School Grand Master
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Felt the urge to post this thread on here, for the benefit and safety of fellow members! Bear with me, it's a long story! :facepalm:

With the weather being cold, but dry and pleasant last Sunday, I lead the better half out and over the Yorkshire North Wolds, to get some hills in, as she has just taken delivery of a new scoot and has a lot of miles planned for this year.
The roads up here are very quiet and remote and not too badly potholed although they are mainly chipped tar, with some nice big climbs.
About 9 miles into our ride, we were travelling down a narrow but relatively smooth straight downhill, but not that steep, section at around 50/55K, when I was scared half witless by the loudest bang (very similar to a .22 at close quarters,) followed by the instant deflation of my front tyre! The crack was so loud, when after a bit of a tussle and practised bike handling skills, I got safely stopped, my ears were actually ringing for several minutes afterwards.
The Mrs was 2/300 meters behind and she thought it was a gunshot or bird scarer.
After up ending the bike I found a small V shaped cut in the sidewall where it meets the treaded section (I'll post pics later), this puzzled me, as I was on straight section of clean road, the tyres had only done around 30/35 miles and this area of the tyre wouldn't be in contact with the ground and the hole in the inner tube was perfectly round and about 3mm in diameter. :? Bit narked as even discounted GP 4000S 11 are not a cheap tyre.
I put a patch on the inside of the tyre, a new tube in and we set off on our loop and eventually home.
Incidentally, I run these at 90psi, well below the 120mm max recommended.

I was still a bit shaken, but none the worse and as I was cleaning both bikes down, my head was full of "what ifs"- corners, wagons, been going much faster car coming past etc etc.
I'd initially thought a flint or piece of metal, but the tyre went down too fast and the hole in the tube and shape of the cut, more like a split along the threads, made me feel it was more like a blow out.
I'd had one puncture on me last year, not as violently, but the hole in the tyre was in the same place and the "hole" was the same profile and again on the same Conti GP 4000s 11 Mmmmm!
Anyway off to the LBS to buy a replacement pair, which opens 7 days a week and are a great bunch of folks!
This is where it gets intriguing! I explained what had happened in the shop (Tyres not bought from there and they are all keen riders/racers) Reply came back "That's why we don't stock Conti!" although they admitted they were asked for them a lot by customers and could sell them, but they felt that at the price they would be paying for them wholesale (really cheap) they questioned QC on them.
Now I've always run Conti' and been happy with them on all fronts-Until now, when my riding confidence with them has been badly shaken:- so bought a set of Bonty R3 lites in 25mm width, (The Conti GP were 23mm) with the understanding if they didn't fit the bike, he'd swap one for a 23mm. The side walls on the Bontys felt sturdy, despite the 200g weight compared to the Conti's sidewalls.
I've wanted to run 25's on my Look, better ride, less rolling resistance etc, but the Conti 23's were just a nice fit with 2-3m max above the tyre to the rear Wishbone, but plenty of clearance for a 28 on the front. No way a 25 would fit the rear, (I'd tried last year and it contacted the carbon)
After the usual tussle with new clinchers, I got them on and inflated, Mmmm, these look smaller than the Conti' despite being 25's, so I measured them at 25.1mm with my micrometer. Ever more weird eh?
So I re fitted the remaining good Conti tyre back on the rims and measured them, bearing in mind these were 23mm, they measured 27.1mm! That's 4mm over size, needless to say the Bonty's fitted the rear with plenty of clearance. All on the same rims.
Now many will know Conti GP 4000S 11's, tend to win all the reviews, for Speed comfort etc, well if you make a tyre with ultra thin side walls that's a lot bigger volume, it's bound to give a superior ride and with the low weight, it will roll well too. How can you compare for ride comfort a tyre than is 4 mm plus wider than it's peers! No wonder they feel good! But at what price to rider safety eh?
Being originally an engineer, I'm thinking, now let's take another look at the blown Conti, sure enough, where the hole was, the side wall was literally paper thin, really, really thin, worryingly so.

I honestly do feel that these tyres are really not safe to use. I then went on line and found that this was a very much more common problem than you would think, not just in the UK but all over the globe and that, virtually no warranty replacements were issued and there was a school of blaming the rider or "flints" etc, as of course offering a replacement would be deemed as being an admission of fault.
It is also interesting to note, that very few Pro teams now use Conti tyres and I found a few reviews on line, were Conti sponsored riders had been fed up with sidewalls splitting etc.

As my late great friend and hero used to say, "When I analyse the stench, to me it now makes perfect sense!"

You always associate German manufacturing with quality, but after the VW Debacle and now my experience with "handmade in Germany" cycle tyres, it makes you question.
I could justifiably complain to Cambrian, but what's the point, they would only offer me some half price tyres the same, no better to march with your' feet and spread the good word to others.
I wasn't thankfully hurt, but could so easily have been or worse. I know some folks will stick up for Conti', but I won't be, just read the reviews I say, you have been warned!

Sorry to go on a bit fellow members, but needed to explain in full.
 
Re:

Interesting, as I'm a conti man. GP4000s on the summer best bike, gatorskins ranging from 23 to 32mm on everything else. I'll keep an eye out
 
Re:

Firstly, I'm glad you're still here to tell the tale :shock:

I had a similar 110psi - 0psi years ago on a steep straight descent, with a bend at the bottom. Front tyre. I stopped at the kerb on the other side of the road. (Left hand bend).Thank goodness nothing was coming the other way!
I imagine mine was a Michelin Super Comp though. It was in the mid '90s.

It could be anything in the road that would cause this.

I had another one about a month ago, using a Vittoria Corsa KX-EVO 20mm tyre. With 290tpi , it's not the thickest wall tyre you will find, so easily damaged.
As for the size, surely it all depends on the way the companies measure. Pressure put in, min or max, or something in between. Along with the rim used for testing on. Not all rims are the same width are they?

Mike
 
Re:

I've had blow outs on Vittoria,Michellin and Bontrager tyres.Race tyres are thin if you catch a piece of road debris they dont like it.The Michelin that went was on a really clean stretch of our ten mile tt course.I stopped and checked the road but found nothing.It happens.
 
Re:

I think the hole was too far over, to have been road debris and the hole has a weird shape, like a V must get some pics up, as have two tyres very similar now. Loads of bad reports if you surf around and all the same issue, side wall failure on near new tyres. I've been on and around bikes for over 50 years, watched all sorts of racing and in town centre Crit's witnessed loads of flats, but never witnessed a tyre on a road bike blow out like this before.
My advice would be to never ever use them or let any of your family either. I'm not saying all Conti tyres are poor, just this model.

Check these out:-

http://www.roadbikereview.com/cat/wheel ... 89crx.aspx

http://www.bikeradar.com/forums/viewtop ... f95b0100d4

https://www.youtube.com/watch?v=NiPBo0hdrvA
 
Probably any sidewall failure will be a similar shape once the fabric starts to tear as it will go along the weave. It must be a very nasty experience indeed.

I've recently seen similar remarks to yours on the CTC forum about GP4Season and in the past fragile sidewalls on Gatorskins was an issue. I used GP4000S II for last season without complaints.
 
Re:

Same with me, been a loyal customer for many years until last year. I did a bit more research and it appears the few Pro teams who use Conti, favour the Grand Prix GT, which is a "heavier" version of the 4000S 30g heavier and double the thickness side wall and wider puncture protection band.
I've since heard of further similar blow outs, that resulted in written off very expensive wheels, with no chance of any recourse back from Cambrian.

This sort of review is exactly what I experienced and seem all too common


Strengths: NONE.

Weaknesses: Do not but these tires. I set them up correctly followed manufactures PSI recommendation. I had a blow out on my second ride with these tires on smooth payment!!!!. I have been riding for 20+ years never had a blowout like this. DO NOT BUY SERIOUS FLAW IN DESIGN OF SIDEWALL.

Bottom Line:
DO NOT UNDER ANY CIRCUMSTANCES PUT THESE ON YOUR BIKE!!!!!!!






Overall Rating:
1

Value Rating:
1
Submitted by JDWESQ

Date Reviewed: August 20, 2012

Strengths: Light weight

Weaknesses: Blew out on first ride. Pumped to 115psi, supersonic tube, Zipp 303 all carbon - 5 miles into the ride it blows. Couldn't find any glass or metal, new tube, pump up - and blows while I'm still holding the wheel. There is a 3mm slice across the tire that goes all the way through. No cutting - just a tear in the tire. Major manufacturing defect. How can they sell crap like this?

Bottom Line:
Quality control sucks - no customer service or contact info for US
 
Re:

These tires are well known for weak sidewalls & blowouts on this area.

I had two go & they are a rubbish tire with a dead feeling on the road. Would never recommend them. Veloflex master or corsa are great responsive & suprisingly tough. Schwalbe Rubino also a good winter tire.
 

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