Cold nuts cause a flat!

[belfastguzzi]

I had a flat rear tyre today. Of course I thought that I had a puncture. After pushing it a bit, but mostly riding slowly on the flat tyre I got the bike to work. On closer inspection I saw that the nut that holds the valve in place, in the rim, had disappeared and the valve was sitting loose in the hole. It seems that the nut had cracked in the cold, split and dropped off!

 

I think they're magnesium valves/nuts. I had a problem with a Ducati magnesium valve cracking before, so that it leaked, but I have never heard of nuts actually falling apart, leading to the disasterous situation of a flat tyre.

 

Has this happened to any of you guys in the frozen northern wastelands?

 

I have a nickel steel valve in now and intend to replace the front one too.

[jrt]

Dude, that's frightening. As soon as I get home, I'm going to check my nuts and warm them up, if necessary.

/sorry-

//wasn't anything worse than belfast would post

 

J

[antonio carroccio]

It could be worser than this. I am glad you haven’t had bad experiences.

[belfastguzzi]

As soon as I get home, I'm going to check my nuts and warm them up, if necessary.

38152[/snapback]

 

I had heard that yours fell off a long time ago? Anyway –

advice: don't use a blowtorch or hot clothes iron.

[Paul Minnaert]

If it was magnesium, that's very corrosive, add some moisture/salt and they are gone. you have to go a lot below zero before these metals loose their strenght. But if it was magnesium, you have mounted them yourself I suppose. The weightsaving doesn't weigh the safety issue here.

[TX REDNECK (R.I.P.)]

It could be worser than this. I am glad you haven’t had bad experiences.

38170[/snapback]

 

 

One time I had a cold & got to coughing so hard, I strained my nuts & they went flat

[jrt]

I had heard that yours fell off a long time ago?

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see?

 

 

Actually, I'm surprised any company would use magnesium in that application. It's prone to oxidize as Paul points out, but it's also very soft. I don't believe I've seen anything but stainless for valves, but I admit I've never looked.

j

[belfastguzzi]

It could be worser than this. I am glad you haven’t had bad experiences.

38170[/snapback]

One time I had a cold & got to coughing so hard, I strained my nuts & they went flat

38255[/snapback]

Yeah we know. You posted the pictures – remember?

[belfastguzzi]

If it was magnesium, that's very corrosive, add some moisture/salt and they are gone. you have to go a lot below zero before these metals loose their strenght. But if it was magnesium, you have mounted them yourself I suppose. The weightsaving doesn't weigh the safety issue here.

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NO. These are the OE valves, as fitted from new. I don't know what they are exactly, but they are certainly not stainless steel. They are a yellow - silver alloy. The tyre fitter described them as magnesium. There was white corrosion on the valve stem where the nut had been, but it certainly could not have been bad enough to have seriously corroded the nut. It had looked normal, at a casual glance. There seems no other explanation than that the nut cracked in the cold, perhaps weakened by some corrosion. This is still the original tyre. The valve / retaining nut had not previously been replaced, adjusted, stressed or abused in any way.

 

Do some V.11 wheels come fitted with stainless valves as standard, then? I wonder what the bikes 'up North' have. Maybe this is a complete freak happening, though as I said, there have been related problems where Ducati alloy valve stems have cracked and leaked. The tyre fitter routinely replaces these with steel.