Valve stem coming lose, help!

[Poker]

My inner tube seems to get the valve stem tore off of two of my tubes now. What I know is the tubes are airtight, the only hole in them is where the valve stem used to stay. I'm on my last spare tube and I need to figure out what's wrong before I put it together again.

Both times I was riding straight ahead on flat ground doing maybe 15-20km/h. And I would feel on the vibration I have that my tire was flat.

The first time it happened was my first time riding in deep fresh snow.

The second time it happened I managed to ride about 50 meters with a new inner tube before it happened again. I purposefully had 1,4 bar (20 psi) that felt more than plenty, I'm like 90kg fully geared.

Could it be my rim is cutting into the valve stem?

Am I missing some sort of rubber protection that's supposed to be mounted between the valve stem and the rim hole?

Am I using too much Vaseline when mounting the tire so that there is not enough friction between the inner tube and outer tire?

There's a few dents in the rim and a small fracture on the edge of it but no sharp edges that I can feel and the leak is basically happening around the valve stem or the valve stem getting ripped from the inner tube.

 

Also not important question but is there a way to attach the lose valve stems to the inner tube again or is it just trash once it gets ripped out?

Edited March 18 by Poker

[Funky]

Same thing happened to me. Luckily it was at the end of ride and right next to my house.  

I was riding normally and suddenly could hear noise. It sounded like something was in wheel well. I checked two times, once even turned whole wheel upside down middle of sidewalk. - Nothing, continued riding and 1 min later i noticed whole tire went soft.. 

Only hole was the torn of valve stem. Meaning the hole was right around valve stem. But while riding (the moment when tire goes "soft", the valve gets torn off.), because tire got soft and slipped, tearing off the stem.

Have you checked those tires.. These tires have very little rubber around stem. Meaning they can get torn off quit easy.

 

You need to check if valve stem got "play" in the rim hole.. Does it move around while pumped with air? Also try to get baby powder instead of "oily" things around tube/tire.. The powder around the tube will not let tube slider inside the tire. Also i used regular heat shrink on the metal valve stem part - so it sits more tightly into rim hole - less play.. Haven't torn yet..

 

 

Old rubber tubes maybe? Play in the rim hole?(heat shrink the stem..) Tire slipped? There's many things that can go wrong. Quick/fast acceleration may result in tire slipping, if to much soap/oil was used while putting tire on. (I personally don't use any oil/soap anymore. Simply brute force the tire on.)  I don't want the valve getting torn off again..

 

You may use white marker and put a white line on rim/tire - For next time to check if tire slipped. - I did that.

Edited March 18 by Funky

[Punxatawneyjoe]

22 minutes ago, Poker said:

Am I using too much Vaseline when mounting the tire so that there is not enough friction between the inner tube and outer tire?

OMG don't use vasiline, just use dish  soap and water just a few drops. Works better and it rinses right off.

[Poker]

4 minutes ago, Punxatawneyjoe said:

OMG don't use vasiline, just use dish  soap and water just a few drops. Works better and it rinses right off.

I can try that, I know workshops use vasiline when fitting car tires to rims because its cheap, slippery and non-acidic.

 

Thx for the lengthy reply funky, I've washed the rim and tire now and could try putting it on dry, will check that the valve is free on all sides from the rim hole

[Punxatawneyjoe]

29 minutes ago, Poker said:

I can try that, I know workshops use vasiline when fitting car tires to rims because its cheap

I've never seen that but i'm in the states. Sorry for the super brief response i was on my way out the door and figured i give you a heads up. I would also make sure your tire pressure is up. What tire are you using on what rim? Sometimes where the bead sits isn't right and it could slip. I would definitely wash the rim/tire off with some solvent though.

[Funky]

1 hour ago, Poker said:

Thx for the lengthy reply funky, I've washed the rim and tire now and could try putting it on dry, will check that the valve is free on all sides from the rim hole

What i meant is - to "free" can also be a problem.. It isn't good if valve stem moves around, when tire is pumped/set..

While riding the tire may get compressed under rider weight. Making the valve move around.. That's why over time the stem breaks off.

To much play is the problem. (That's why i added heat shrink around the valve stem. So it sits more tightly, less play.)

Edited March 18 by Funky

[Poker]

54 minutes ago, Punxatawneyjoe said:

I've never seen that but i'm in the states. Sorry for the super brief response i was on my way out the door and figured i give you a heads up. I would also make sure your tire pressure is up. What tire are you using on what rim? Sometimes where the bead sits isn't right and it could slip. I would definitely wash the rim/tire off with some solvent though.

 

Its a V11 with a 80/90 - 14 Michelin city pro wheel. It fits nice. Thanks for the advice!

19 minutes ago, Funky said:

What i meant is - to "free" can also be a problem.. It isn't good if valve stem moves around, when tire is pumped/set..

While riding the tire may get compressed under rider weight. Making the valve move around.. That's why over time the stem breaks off.

To much play is the problem. (That's why i added heat shrink around the valve stem. So it sits more tightly, less play.)

Mounted it totally dry and pumped it up now. Now I get what you meant with heat shrink, guess I'll be patient and wait until Monday to buy some instead of risking my last inner tube.

thanks again