jsidney

While adding air with a portable pump the bike fell over and the tube stem popped out. I have not taken the tire off yet to check the tube but I see nothing torn on the stem.

What I see on the stem is what appears to be a rubber grommet, can this be put back into the tube or would you just get another tube.

WNCGoater

I am assuming you mean the valve CORE came out of the tube. If that is the case, yes, the valve base(The base of the whole valve core) screws into the valve sheath or valve tube(Not sure of exact terminology). Then the top of the valve core screws down into the base to allow for sealing or opening to allow air to enter (or exit).

jsidney

Not the valve core, the entire stem came out.

When the bike fell over I was still holding the pump in my hand and the stem was still locked into the pump head.

WNCGoater

The only way for the whole stem to come out would be for it to tear loose from the tube. In which case the tube is ruined.

indyfabz

Yeah. The OP makes no sense.

jsidney

What came out looks kind of like this. The grommet is a little different in shape and it has a groove around it.

https://www.backcountry.com/stan-s-n...RoCPXgQAvD_BwE

indyfabz

Are you trying to troll us? That's a stem for a tubeless rim. Either way, if a stem broke completely off a tube or you pulled a tubeless stem completely out of the rim, the tire would lose all air. In the case of a stem ripped from the tube, the tube would be toast. Simple as that.

jsidney

Not trying to troll at all, I also did state that the photo was of one for a tubeless set up but what came out of the tube was similar except it has a deep groove around it.

It did lose air as the bike fell over and the stem tore out.

The rim is for a Schrader tube but have been using Presta with an adapter. It does seem I forgot to put the adapter in during the last tube change and the rotating ring was loose, that probably contributed in the stem comming out easier.

On the stem that came out of the rim I don't see any torn bits, just the the stem and a rubber grommet. I will know more when I take the tire and tube off tonight.

No troll going on at all.

indyfabz

With all your experience, one would think you would know the tube is toast.


Bub-bye.


/thread

jsidney

I assumed that would be the case and expected to see torn rubber around the stem but instead it is a grommet with a groove around it and no evidence of tearing.

Iride01 

In all fairness to the OP, you should believe him. In fact I had a presta stem come completely out of an inner tube also and it was a very clean separation from the tube and had a little patch of rubber near the bottom that was similar to the stems for tubeless tires.

Mine came out because the locking head on my air hose had not been releasing fully and I had to yank it every time I filled it for over a year. After pulling it out I replaced the air hose on the pump with a replacement from Nashbar and now it works better than ever.

Trying to re-install the stem might be something that's possible, but probably not trustworthy and will likely need tender handling every time it's filled. Something one should only do when they want to prove the others wrong.

As tubes don't cost much, why bother with the trouble.

edit.....

Daay-anng ! just noticed the price of those stems. I can get four tubes for that.

jsidney

My current location has no bike stores of any type. I will order more tubes so not that big of a deal, I will just have to wait.

I was shocked when the stem showed no evidence of tearing so I thought others might have seen this before and may have been able to fix it successfully getting me back on a bike faster.

Iride01 

You got a Walmart there in Ponca City. These are what I buy.... https://www.walmart.com/ip/Bell-Tube...Valve/34038251

And before someone says that's why my stem came out...... It came out of a Continental inner tube that I had at the time.

jsidney

The last time I checked had no 700c tubes, it seemed everything had gone to smaller diameters. I will take a look but will still order some tubes as well.

The tube that lost the stem for me was Giant brand. I wonder of those are made by Continental.

Milton Keynes

I don't think I'd trust it at 80-90 PSI. With my luck it would shoot out at high speed as soon as I mounted the bike. Or wait until I'm 20 miles down the road.

wphamilton

I almost never see any 700c tubes in Walmarts around here either. I just skip the trip and internet order from your preferred vendor.

Gresp15C

I've had the same failure on presta tubes. Where the stem joins the tube is delicate. Knowing this, I am now much more careful with presta.

79pmooney

The adopter is, I assume, a fancy washer that narrows the large Schraeder hole to Presta diameter. Not having that adopter (or a common washer to do the same thing) you are asking unsupported innertube to resist a lot of pressure. It sounds like the tube you used was made in such a way that you "could" reassemble it with the appropriate glue and re-use it. Most of us would say life is too short to try but if you were successful, you might have a working tube in place before FedEx arrived.

Ben

bogydave

????Probably contributed????
OK.
Logic. Using wrong tube.
Why not use Shrader tubes for shrader rims?

Yea
Interesting but logical
Operator error
I’ve been guilty of making stuff work ,
When necessary,
Knowing it could fail

jsidney

It is quite common for people to use a Presta Tube on a Schrader rim with an adapter. Plenty on this very forum do it without the adapter but it is not recommended. I simply forgot to put the adapter in place on the last tube change.

I don't know if it contributed or not, I think the fact the locking ring was not tight was as much or more of a factor.

jsidney

It was this forum that got me using Presta Tubes on Schrader rims. I have since found the Touring bike crowd do it a lot to have an easier time finding replacement tubes in small out of the way places.

There is nothing wrong with using Presta Tubes on Schrader rims as long as you have an adapter. It if is worth it or not is a different question.

A lot of forum members also say the adapter isn't important. Quite a few people on the forum claim decades and thousands of miles of no problems running Presta on Schrader rims.

Doing what I have been doing is in no way unusual.

SouthFLpix

I used to buy those also, and they work just fine, but now I have deeper dish rims and the valve is too short. An extension works fine as a temporary fix, but in the future I would prefer buying tubes that come with longer valves.

alcjphil

I have my touring bike set up that way for the same reason. If I ever needed an inner tube while on tour and could only find Schrader valve tubes I could remove the adapter and use them. I wouldn't use Presta inner tubes without the adapters however

CliffordK

Old tubes had the valves more or less bolted down. But, I haven't seen those for eons.

Nonetheless, I'd try the repair out. You can't be any worse off than you are now.

The outer lock ring is unnecessary, and should only be finger tight. Its main purpose is to help one push the pump on the valve, I think. But, the tube will work just fine without it.

As far as department store tubes... I've used them off and on. It is the oddest thing. They often have a shelf full of 20" tubes, but have the space, but no tubes of narrow 700c - 18/25 tubes, or perhaps even the next size up. My guess is that they sell out of those quickly, and nobody has bothered to try to get a better estimate of actual sales.

The other thing that likely happens is that they'll sell the 20" tubes in singles, but for the 700c tubes, an avid cyclist may come in and clean off the shelf.

Nonetheless, it never hurts to check.

jsidney

I checked Walmart online. It looks like it is all 20 and 26 inch.