Stan tubeless leaking at the valve stem

I changed the valve stem on my Stan wheel but it keeps leaking. Is there a trick to make it seal properly?

It is a new valve...

 

Is it leaking from around the base of the stem?

 

Happened to me. i just removed the stem and cleaned any stans from the black rubber o-ring with warm water and a soft toothbrush. Never a prob since. Also make sure that the piece the stem srews into is clean using a very small bottle brush. Could also be a faulty stem even though it's new I guess?

 

Is there an o-ring missing? Happened to me once with the valve on a UST setup. Just thought I'd state the obvious since at least once it wasn't obvious to me.

 

Is it a slow or fast leak? Submerge it under water or spray it with some soapy water and see if it is leaking around the stem or at the valve core. If it is at the core, try tightening it. If it's around the stem, try tightening the valve stem nut 1/2 - 3/4 of a turn past finger tight with pliers.

Check to see if the tape has been compromised. If so, replace it. If not, and it's leaking around the valve stem, you may need to build up the valve hole area a little bit underneath the Stan's rim tape or whatever sealing tape you are using. Try a layer or two of electrical tape. Just don't go crazy and layer the whole rim. A 2" strip should be more than enough.

Are you using Stan's rims or Mavic rims with the Stan's Mavic specific valve stem?

:-k The only UST rims I remember that use o-rings are the Mavic UST rims. I could be wrong here since I haven't been keeping up with technology in quite some time.

The OP stated he has Stan's wheels. I'm not sure if he meant that he has a wheelset built using Stan's rims or that he has a wheelset made tubeless using the Stan's kit or some variation of it. :?:

 

Tighten the stem nut. Real tight.

Final step, hold the wheel horizontal with your hands 90 degrees away from the stem flip the wheel up and down. You're trying to make the liquid slosh over the stem.

 

+1 on this advice.
More often than not the stem is the last place to seal on my tires.

 

Just put a bead of silicon around the valve stem on the inside of the rim, tighten down the nut on the outside and let dry over night. Should solve your problem.

 

they are Stan rims, it is a Stan stem, I tighten the stem nut. It is a pretty fast leak, I can hear it and it gets worst if I touch the stem.

I will clean the stem real good, then try the horizontal slosh trick. I will post the results tomorrow.

Thanks

 

Stans sells TWO different vale stems. One for their rims and one for "other" rims. They look almost identical but there is a slight difference in size and the shape of the rubber seal.

For Stan rims you need this one
http://www.notubes.com/product_info.php/products_id/123

For "others" it would be this one
http://www.notubes.com/product_info.php/products_id/41

 

Now for the ultimate "trick". It undercuts Stans income but saving money is good for me ...

Cut the stem out of an old tube. Trim around the base to fit/seal the rim. If fluid dries up I break the bead, pour in liquid, and re-seal with a compressor.

I don't bother injecting liquid through a removable valve core, that always seems messy and slow.

 

It's pretty messy and slow if you use the Stan's injector kit.

I've found the best way is to use the little squeeze bottles. Just fill them up with sealant, remove the core, and squeeze.

 

I'm going to disagree with tightening the stem nut overly tight. This causes two problems. 1 - it deforms the rubber seal which I'm guessing is what your problem is, and 2 - unless you carry a pair of pliers with you in your pack, you won't be able to remove the stem if you get a flat and need to install a tube.

 

I agree. That's why I only recommend a 1/2 - 3/4 turn past finger tight. You will still be able to remove it with your bare fingers out on the trail if need be. The other potential problem with doing that is that you may weaken the base of the valve stem and cause it to pull through the rim during subsequent times when you are inflating the tire.

I've been doing the valve stem from the old tube "trick" with much success. You just have to be a little more careful not to over tighten the nut as the base on the old tube stems are not as thick as the Stan's valves and are more prone to valve hole pull through than the Stan's valve stems.

 

a dab of vaseline (petroleum jelly) works too