BLOWOUTS: MAVIC KSYRIUM EQUIPE + CONTI GP4000S

joze1980

Last season I've bought a new bike and had 3 tire blowouts on the rear wheel.
Blowouts weren't caused because of running over a sharp object etc.(tire itself wasn't damaged),
but because tire slid off the rim on one side on area long 20-30cm. Then inner tube of course popped out and exploded. Third explosion even happened not while I was riding the bike, but while the bike was sitting in a garage.
I was double checking, that everything was done right during installation of a new inner tube every time. Pressure was allways at 7-8bar.
This season I bought new GP 4000S tires and have them installed by a professional and after just 400km experienced another blowout, this time on a descent - I crashed and broke my collarbone.
Now I suspect that wheels are causing this, as I can hardly believe that I had such misfortune and bought
3 defective tires in a row.

Has anyone else experienced similar problems with these tires or wheels?

Thank you all for your responses!

Joze

pride4ever

No never owned a pair but I,d chuck them away pronto mate.

slowandsteady

I've had this once and it was due to me pumping way too much air into the tyre.

Are you sure the guage isn't reading incorrectly?

ddraver

I use the exact same set up as you (and probably weight considerably more). Sounds like there is something wrong with the rim and it's not holding they tyre well enough. Have a really good look and see if you can see anything then start the (unfortunately) interminable Mavic Warranty process...

CrouchingPig

literally just fitted some 4000S to my Equipe's (not yet ridden the wheels!), this thread fills me with confidence before my ride!

mamba80

My first reaction to reading this is " why would you carry on using this set-up ? and is this a wind up???? "

you should go back to the shop and ask for replacement wheels/tires surely? a broken collar bone and crash is serious, you could have been killed - your brake blocks arnt touching the tire at all are they?

goonz

Is the rim tape in its proper place and spokes not pushing through at all?

andrewjoseph

have conti 4000s 25mm on our bikes, no problems. no worries coming down 30km descent from mt.teidi.

kettrinboy

Ive been using Equipes/GP4000S combo for around 4 yrs now and the only issue ive had was with the valve holes in the rims having a sharp edge or burr which could cut into the tube around the valve neck, that caused a few flats until i deburred the hole and had no bother since after 20000+ miles to date, and certainly no problem with the tyre actually coming off the rim.

halfround

I have run this combo for thousands of miles, no problems at all. Are you using the rim tape that came with the wheels?
If the rim tape is to thick or thin it can cause problems. Let the air out of the tyre and you should have to pull the bead away from the rim all the way round. That way you know it is seating as it should.

earthvspace4XTuUWcX

As sloandsteady says above I would suspect overinflation, try a different pump/gauge. In most circumstances even if your 7-8 bar is accurate it is too much.

joze1980

I weight 75 kg, so that shoudn't be an issue.
I used different pumps, so i would rule out faulty pump gauge too.
A friend who works in bicycle repair shop checked the rim tape and position of brake pads... nothing.
It obviously isn't a common problem and I really got unlucky , as I searched some other forums and found nothing similar.
Because it is a Canyon bike, I wrote complaints directly to continental (they 've sent me 3 new tires) and mavic (no answer).
Anyway, I am buying different set of wheels and tires and hoping it is going to be ok afterwards.
Here is a pic of the rear wheel.

ddraver

There's no doubt it's a wheel problem (pun very much intended). How you l ever convince Mavic of this though I ve no idea, might not ever be worth the bother

josehernandez

Bought a brand new pair of GP4000s' a month ago and experienced a high speed blowout on my rear after only a weeks use. Tyres were so new they still had the the little bits of rubber sticking up from centre of tread. LBS thought it sounded like a known Conti manufacturing flaw. Had to buy new rear :evil: and thankfully I've had no further issues.
Ironically I changed from Ultremo ZX's to the 4000's to avoid this kind of thing but the more I research the subject the more it seems luck with tyres is a complete lottery.

joze1980

Exactly, proving that it was caused by faulty rim would be probably impossible.
And what's more I don't know if i can trust mavic again.

buckmulligan

Well, first thing I'd inspect is the clincher lip on the inside of the rim because obviously this sounds like the issue. If there's an obvious defect I think you'd have a good chance getting a replacement from your shop or Mavic, since it should be clear whether it was the cause or the effect the blowouts.

I certainly wouldn't have carried on riding a set of wheels after having two blowouts! Get some new ones ASAP.

gryfon23

Does seem a little odd. As others have suggested, check the lip of the wheel and compare it with the front one.

Has it always come off in the same place on the rim?

joze1980

Just got out of the hospital - collarbone surgery.
I checked the lip, but there were no visual defects there. It came off on different places.
After i'll get better i'll merasure different measures of the rear rim and compare them with front.
I will probably write to mavic again and hope they don't ignore me again.

ck101

I ride Ksyrium Equipes also and had two blow outs last year. I was inflating to between 115 and 120.

I now inflate to 105 and havent had a problem since.

nferrar

I'm 90Kg and never inflate road tyres past 100psi, there's simply no need. As to the OP - was the rim not damaged after the blowouts? A mate had an Ultremo blowout and stopped pretty quickly after, the rim was pretty badly scuffed/damaged though and needed trashing as wasn't safe to ride any more. I'm surprised you've had 3 blowouts and possibly still using the same wheel.

Pross

Are you sure the tyre (not tire!! :evil: ) coming off the rim is causing the blow out and not the other way around?

joze1980

If declared max pressure for wheel is 9bar and for tyre 8.5 bar, then overloading is not the case here.
Rim was not damaged until now. First blowout happened going uphill at 5mph, second while bike was in a garage and third going slowly on a flat road. In first two cases i could clearly see around 30-40cm of tyre fell of the rim, tube in that area popped out and was thorn apart as you can partially see it in the photo in my earlier comment.

giant_man

This is very strange gotta say. No joke as the op's collar bone surgery verifies, hope this is sorted.

jonny_trousers

This means very little, but the beading on the first GP4000 I bought was nowhere near right. I've always assumed it was a one-off.

Bar Shaker

With so many GP4000S in use and one of the most popular wheels out there, that between to two there is a manufacturing defect is almost a mathematical probability.

I suspect the problem is with the wheel but surely it would be better to check that out before posting on here and leaving everyone to guess. Finding a cause cannot be that hard, especially if it has actually happened 3 times and has resulted in injury. I think I would have investigated this after it happening once, but hey ho.

This wouldn't stop me buying either component.

monkimark

I rode that wheel/tyre combination for 6 months (until my chain snapped, jamming the wheel & causing me to skid down the road at 50km/h until the tyre wore through) and the only blow out I had was when I hit a particularly vicous pothole.
I run the tyres at around 110psi but don't check every day so it's probably below that for a fair bit of the time

madbiker2007

I got GP4000s and have had up to 50mph on them with no faults so far. They do have lots of hairline cracks however. The problem sounds like its your wheels. If its coming off the rims then either the tyre size is incorrect or theres some fault with the rim where the tyre sits. Get a professional to have a look at it rather than just taking it to a bike shop.

junglist_matty

I got my Canyon (Ultimate AL) with the same Mavic wheels and the same GP4000s's (23mm) as you have; I've had no problems, after just under 3000 miles, I changed the tyres to GP4000s (25mm), and now with 1000 miles on the new set, had no problems that you speak of..... I weigh in at 210lbs, so considerably heavier than you.... My tyres are very tight on the rims; they're quite difficult to get off with plastic tyre levers, but not impossible!