Campagnolo zonda on Pinarello
monet
Posts: 7
Hi Guys,
I would like to know if anyone of you had similar experience to one I had described below.
I was riding a brand new Pinarello with Campagnolo Zonda wheel set competitively and was taking a sharp bend , to my surprise the valve on the front wheel snapped deflating the tyre instantly. There was no pot hole, bumps or any kind of impact on the front wheel.
Only notable thing is that the front wheel valve did not have a valve nut. On inspecting the tube I could see the remaining piece of value inside tyre. No cuts on the tyre, it is new. I would say about ~ 2cm of the valve got cut off from the wheel.
Does this suggest that valve nut is necessary, if not what could cause a valve to be severed off while riding at a speed of 18mph-24mph.
Tyre pressure would be between 85-100 psi . Any input would be informative.
I would like to know if anyone of you had similar experience to one I had described below.
I was riding a brand new Pinarello with Campagnolo Zonda wheel set competitively and was taking a sharp bend , to my surprise the valve on the front wheel snapped deflating the tyre instantly. There was no pot hole, bumps or any kind of impact on the front wheel.
Only notable thing is that the front wheel valve did not have a valve nut. On inspecting the tube I could see the remaining piece of value inside tyre. No cuts on the tyre, it is new. I would say about ~ 2cm of the valve got cut off from the wheel.
Does this suggest that valve nut is necessary, if not what could cause a valve to be severed off while riding at a speed of 18mph-24mph.
Tyre pressure would be between 85-100 psi . Any input would be informative.
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Comments
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Did the part of the valve that was lost not have the nut on it?
And did you recover that part?Advocate of disc brakes.0 -
How do you know that was the sequence? It's more likely that the tyre punctured and then, given the lateral movement, the tyre/tube moved away at that point and took the valve with it. It should seat very well under pressure even without the nutMy blog: http://www.roubaixcycling.cc (kit reviews and other musings)
https://twitter.com/roubaixcc
Facebook? No. Just say no.0 -
On a scale of 1 to 10, how competitively were you riding?0
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When you said the valve snapped suggests that the metal body actually sheared, which takes an incredible amount of force, which would simply not have been present. Do you, perhaps, mean that the valve ripped away from the inner tube at the base?
I've had several instances of valves detaching from inner tubes, on different makes of rims/wheels. The model of the bike is irrelevant. The common factor in all my instances of valve/inner tube failure was the inner tube being Vittoria brand (yellow dust cap). After this was determined, I no longer bought Vittoria brand, either tyre or inner tube, as I also had issues of Vittoria tyres coming unhooked from certain (presumably compatible) models of rim.
At every opportunity, I buy Michelin 52mm valve length inner tubes. Michelin were stated as being the last known brand manufacturer to make their own inner tubes. I run with Continental GP4 Seasons on Campagnolo Khamsin, Continental GP4000s on Campagnolo Scirroco and Continental Attack/Force on Planet X Pro Carbon 50s. I like the smooth valve stem of Michelins, as it makes removing the pump hose easier.To err is human, but to make a real balls up takes a super computer.0 -
Did the part of the valve that was lost not have the nut on it?
And did you recover that part?
part of the valve that was cut off wasn't recovered. But it did not have nut on it because the bike came from the factory with no nut for zonda wheel set. Rear wheel still doesn't have nut on it .0 -
How do you know that was the sequence? It's more likely that the tyre punctured and then, given the lateral movement, the tyre/tube moved away at that point and took the valve with it. It should seat very well under pressure even without the nut
I can confirm there was no puncture at all on inspecting the tube, apart from snapped valve. Besides if there was to be a puncture it has to be a full blown puncture as the deflation happened immediately, so must be very obvious on inspecting the tube.0 -
When you said the valve snapped suggests that the metal body actually sheared, which takes an incredible amount of force, which would simply not have been present. Do you, perhaps, mean that the valve ripped away from the inner tube at the base?
I've had several instances of valves detaching from inner tubes, on different makes of rims/wheels. The model of the bike is irrelevant. The common factor in all my instances of valve/inner tube failure was the inner tube being Vittoria brand (yellow dust cap). After this was determined, I no longer bought Vittoria brand, either tyre or inner tube, as I also had issues of Vittoria tyres coming unhooked from certain (presumably compatible) models of rim.
At every opportunity, I buy Michelin 52mm valve length inner tubes. Michelin were stated as being the last known brand manufacturer to make their own inner tubes. I run with Continental GP4 Seasons on Campagnolo Khamsin, Continental GP4000s on Campagnolo Scirroco and Continental Attack/Force on Planet X Pro Carbon 50s. I like the smooth valve stem of Michelins, as it makes removing the pump hose easier.
Apparently it is the metal body that got sheared from the inside point of contact on the rim. I can confirm the tube was Vittoria brand that came with Vittoria zaffiro pro. I never had this problem on any other bike . When I inspected the rim ( Zonda) the tube hole itself appear to be very sharp around the edges , when stationary the tube did have significant lateral movement even at a pressure ~ 80-90 psi0 -
Apparently it is the metal body that got sheared from the inside point of contact on the rim. I can confirm the tube was Vittoria brand that came with Vittoria zaffiro pro. I never had this problem on any other bike . When I inspected the rim ( Zonda) the tube hole itself appear to be very sharp around the edges , when stationary the tube did have significant lateral movement even if a pressure of at least 80-90 psi
Amazed! The tyre must have shifted on the rim to allow the valve to twist and shear against the valve hole.
I suspect that the threads of threaded valve stems are cut, rather than rolled. Being an Engineer, I know that the material grain flow in machined (cut) products is interrupted by the removal of material. If the threads were rolled in, the grain would be squeezed into shape. The difference is that valve stems with cut threads have stress points along their length, whereas rolled and plain shaft stems have none. With the stress points, cut stems are more liable to shearing at those points, but it would be rare.
Looking at two different inner tubes, the layman wouldn't know the difference between a cut thread or a rolled thread. Since cut threads would be cheaper to make, I suspect they will be common in mass-market inner tubes. Best to go for plain shafted valve stems (Michelin), IMHO.To err is human, but to make a real balls up takes a super computer.0 -
I think you are correct,It broke at a stress point. I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel. It appears that this particular tube I had on the bike I could break it with my hands, something wrong with the material they had used.0
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I think you are correct,It broke at a stress point. I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel. It appears that this particular tube I had on the bike I could break it with my hands, something wrong with the material they had used.
Seems suspiciously so.To err is human, but to make a real balls up takes a super computer.0 -
I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel.
Or you could just buy new tubes.0 -
I think you are correct,It broke at a stress point. I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel. It appears that this particular tube I had on the bike I could break it with my hands, something wrong with the material they had used.
I'm not sure what a martial analyst could usefully tell you. I'm not even sure what one is.
Even a material analyst might have a quiet giggle at being asked to examine a popped tube.
By all means send it, but the essential lesson here is that tyres do pop sometimes. And sometimes they don't.
Yours did. Mine will. It happens.
I put nuts round the bases of my tyre valves. Many cyclists do not. It's just a bicycle.
Are you really interested in the findings of the analysis or are you thinking of claiming some sort of payment from one or another party?
Buy good tubes. Be careful how you put on and inflate your tyres. It's just a bicycle.0 -
I'm not sure what a martial analyst could usefully tell you. I'm not even sure what one is.
I have used the services of a material analyst many times. They can section the broken valve, to tell you if it was a cut or rolled thread, take macroscopic photos to highlight micro cracks and test the physical properties of the material, to find if it was up to the job.To err is human, but to make a real balls up takes a super computer.0 -
I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel.
Or you could just buy new tubes.
and then move on....0 -
I'm sending the tube to be examined by a martial analyst to get more information, I have similar tube on the rear wheel.
Or you could just buy new tubes.
I'd second the call to buy new tubes, but qualitatively exposing Vittoria for producing crap inner tubes would be of value to all of us.To err is human, but to make a real balls up takes a super computer.0 -
One failed inner tube does not mean that Vittoria's tubes are universally crap. It just means that a tube failed, that's all.0
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One failed inner tube does not mean that Vittoria's tubes are universally crap. It just means that a tube failed, that's all.
well it does imply vittoria tube aren't reliable.0 -
I'm not sure what a martial analyst could usefully tell you. I'm not even sure what one is.
Anyone else misread it as martial artist ? Ok just me then
Ninja looking for a crack in his carbon fibre Samurai sword ."The Prince of Wales is now the King of France" - Calton Kirby0 -
One failed inner tube does not mean that Vittoria's tubes are universally crap. It just means that a tube failed, that's all.
well it does imply vittoria tube aren't reliable.
It does nothing of the sort. IMy blog: http://www.roubaixcycling.cc (kit reviews and other musings)
https://twitter.com/roubaixcc
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Bora wheels come with a plastic support collar that should protect the valve from moving. In my experience they are quite easy to dislodge when the valve is pushed through.
This image indicates they should have something, in real close up you can see there is a nut fitted.
http://cdn.coresites.factorymedia.com/rcuk/wp-content/uploads/2012/07/ZONDA2WFmegaG3_post-20131.jpg0 -
One failed inner tube does not mean that Vittoria's tubes are universally crap. It just means that a tube failed, that's all.
well it does imply vittoria tube aren't reliable.
It does nothing of the sort. I
You're right. One failed tube is statistically irrelevant, but I bought several Vittoria inner tubes, and they all failed through design/manufacturing faults. I've never had such issues with any other tyre brands that I tried.
I stick to Michelin inner tubes now, for reasons given previously.To err is human, but to make a real balls up takes a super computer.0
