# Broken rod in presta valve



## milkbaby

I was pumping up my tire but put the chuck on too far, bent the rod, and then it broke off when I was screwing the nut down. Now what's left of the inner rod is level with the top of the valve stem. I kept the plastic valve cap so it can be covered. Is there any problem with riding on this tube? Will I still be able to pump air into it or is it done for once the air pressure is too low to ride anymore?


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## andulong

Just get a new tube!


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## kykr13

I did that once, just before leaving for a ride. Since I was carrying two spares (solo, not the greatest roads, Murphy's law, etc) I decided to chance it rather than taking the time to change it right then. No problems on the ride, but I changed it when I got back.


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## wim

In spite of its frightening appearance, it'll work and can be pumped back up. What closes a Presta valve is internal air pressure against a sealing cone. The screw-down closure is just a secondary lock in case of....hmm...does anyone really know? Discussions about this have advanced theories from "cobblestone riding" to "centrifugal forces at 80 mph opening a Presta valve unless locked down."


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## Kerry Irons

*No worries*



wim said:


> In spite of its frightening appearance, it'll work and can be pumped back up. What closes a Presta valve is internal air pressure against a sealing cone. The screw-down closure is just a secondary lock in case of....hmm...does anyone really know? Discussions about this have advanced theories from "cobblestone riding" to "centrifugal forces at 80 mph opening a Presta valve unless locked down."


+1 More than once I have started to pump my tires and noticed that the "Presta nut" was unscrewed, and probably had been so for a week or so. I think the main function of the nut is to keep dirt from going into the valve. What it's "purpose" might be, I have no idea.


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## milkbaby

Thanks for the help y'all! I always kept the plastic valve caps on because I thought they would help keep crud from getting up in the valves... I don't plan on riding any cobblestone roads OR going 80 mph anytime soon!


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## Camilo

milkbaby said:


> Thanks for the help y'all! I always kept the plastic valve caps on because I thought they would help keep crud from getting up in the valves... I don't plan on riding any cobblestone roads OR going 80 mph anytime soon!


With a presta valve, there is no way that crud can get inside the valve if it is closed. No need for the caps at all, imho.


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## Mr. Versatile

Camilo said:


> With a presta valve, there is no way that crud can get inside the valve if it is closed. No need for the caps at all, imho.


That goes double for the useless round nut that screws on over the valve stem.


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## tihsepa

Its just a tube.


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## sometimerider

wim said:


> The screw-down closure is just a secondary lock in case of....hmm...does anyone really know?


The closure is mainly there to prevent accidental air loss. Anything (such as my own clumsy fingers) that bumps the valve will cause a loss of a few psi. I doubt that normal riding (bumps, etc.) can cause loss. 

Others asked about the valve cap. According to Sheldon Brown, this is only present to prevent punctures while the tube is rolled up.

Others asked about the larger nut that can cinch the stem down to the rim. This can help when pushing a pump head down on the valve. But it clearly isn't needed; I don't use them, and they obviously aren't possible with unthreaded stems.


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## jmlapoint

The tubes like Continental with removable valve cores are nice if you break the threaded rod and wish to exchange them on say a new or expensive latex tube. I have saved several valve cores from old multi-punctured tubes, but have to admit, since saving them, I haven't broken a rod for some time....Good Kharma...

It is possible for a non-removable core valve rod to slide inside a large, completely deflated tube since the base of the stem where it mounts to the tube is an open hole and the valve gasket butts up inside the stem and there is no ridge to prevent the rod from going completely inside the tube. It is also possible to find/feel this piece thru the rubber and reinsert it by grasping it thru the tube. I have actually done this 'sleight-of-hand' magic. However, as long as there is some pressure in the tube, the vavle gasket should be held up inside the stem.

The removable valve cores will not allow a broken-off rod to drop completely inside a deflated tube. There is a ridge on the inside of the stem tube that prevents this. Another good point for removable valve cores, but they only, as far as I know, come with threaded stems.


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## wim

sometimerider said:


> The closure is mainly there to prevent accidental air loss. Anything (such as my own clumsy fingers) that bumps the valve will cause a loss of a few psi.


Yes, that makes sense. Obviously, you need some sort of plunger to unstick the valve before pumping the tube. I suppose the plunger could have been designed to be inside the valve (like it is in a Schrader valve), but then you'd need a tool of some kind to depress it. Since it sticks out, you need to be able to lock it down.


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## Touch0Gray

wim said:


> Yes, that makes sense. Obviously, you need some sort of plunger to unstick the valve before pumping the tube. I suppose the plunger could have been designed to be inside the valve (like it is in a Schrader valve), but then you'd need a tool of some kind to depress it. Since it sticks out, you need to be able to lock it down.


actually, I think that once the air pressure in the pump hose gets higher than the pressure in the tube it will pump up just fine....regularly I have the valves kind of stick closed until the hose pressure gets up to 100 psi or so. (I am probably not pushing the pump head on all the way when that happens.)

I bent the rod on mine last weekend as witnessed by Mr Kykr!...it was fine.....


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## Fai Mao

How do you remove the Valve cores?


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## tihsepa

The tube must be able to have them removed. You cant get them out of every tube.


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## Touch0Gray

A from Il said:


> The tube must be able to have them removed. You cant get them out of every tube.


I am going to find an old tube and see, I mean really, they put them in, they gotta come out don't they? I know a schraeder ha a little core wrench you need....


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## PJ352

Touch0Gray said:


> I am going to find an old tube and see, I mean really, they put them in,* they gotta come out don't they?* I know a schraeder ha a little core wrench you need....


Just cuz you can get them out, doesn't mean they're removable. 

AFAIK all schrader's have removable cores, but re: presta's, Vittoria's and Bonty's do, Michelin's and Kendra's don't. Obviously that's just a sampling of what's available. 

Both need a tool specific to their type for core removal.


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## czacharyasz

dont they recommend you to remove the valve core anyways when using c02 or tubless rims to get more air flow in to seed the tire? im guessing your fine with it broken like that, as long as decent pressure in it, no air will leak...i do notice when you have little air in a presta tube and the nut unscrewed up top, air will leak out...for example, when your fitting a tube inside a tire before inflating...youll hear air coming out, till you get enough pressure for the seal to lock...

its always good to have spare tubes around no matter what, so dont ditch this tube...buy a few spares and use it in an emergency.


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## sometimerider

czacharyasz said:


> dont they recommend you to remove the valve core anyways when using c02 or tubless rims to get more air flow in to seed the tire?


You can get plenty of air into a tube without the valve core, but it will be gone instantly when you remove the inflator.

Oh, you mean "seat the tire"? Yes, I guess that's important with tubeless. Still, when you remove the inflater, the tire will empty. It may stay seated, but to get air to stay you will need a valve core.


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## roadfix

Tu-be or not tu-be...


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## Ibashii

Mr. Versatile said:


> That goes double for the useless round nut that screws on over the valve stem.


Most of the time, sure, but that thing is crucial if you have the double-whammy of a half-deflated tube and a stem that is too short for the depth of the rim; without it it's a PITA to get any inflation device properly seated onto the valve. Now why would that 100% avoidable situation come up, you ask? Because I bought some tubes on sale and the stem length was less than what it said on the box. Store out of business, can't return them. Not smart perhaps, but I'm stubbornly determined to use them all before getting new ones with nice, long, smooth, non-nut-needing stems.


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