Sealant leaking at base of valve stem

[iscarrr]

I've had good success with tubeless setups in the past, but this one in particular is being a pain.

So here's what im working with:

-Stans Crest 29, yellow rim tape, stans valve stems (I've had these rims seal up perfectly before)
-Maxxis Ikon tyres. Haven't used them before, but got them to snap onto the rim without too much work with a track pump.

Anyway, bead snapped on, tyre deflated without touching the bead, valve core out, sealant in, air in, shakey shakey. Left them laying down over night, both still inflated, but when i shake the rear with the valve at the bottom sealant is visibly leaking out from the base of the valve.

I've tightened the valve nut, but its made no difference. I've read that taking the valve out and cleaning all around the the the black rubber part can help. To be fair this valve has been used before and i honestly didnt make sure it was perfectly clean, though im sure if it was covered in dirt i would have noticed.

Any ideas?

 

[quiggs]

I suspect you are going to have to take the tyre off, clean around the inside valve hole of any loose yellow tape, give the black rubber seal a clean and ensure it sits in snug against the inside of the rim valve hole and start again.

hope that helps

quiggs

 

[mtb101]

I suspect you are going to have to take the tyre off, clean around the inside valve hole of any loose yellow tape, give the black rubber seal a clean and ensure it sits in snug against the inside of the rim valve hole and start again.

hope that helps

quiggs

+1 I use plumbers white tape and an extra tightening up on valve. Would consider silastic sealer if not 100% seal. This is one area NoTubes sealant doesn't get to.

 

[mittagongmtb]

mm.. whenever had this problem, twas the rim tape slipping off and allowing sealant to get into the spoke hole or other small holes. Check the tape.

 

[Antsonline]

I had that problem with Crests before, as did the missus.

It was remedied both times with some new yellow tape.
I also put a rubber 'o' ring on both sides of the rim (internal and external) for added peace of mind.

 

[iscarrr]

Thanks for all the tips guys, exactly what i wanted.

I think ill clean around the valve hole and the valve stem first, if that still fails can try new tape.

For those who mentioned plumbers tape, did you just wrap it just above the black rubber base of the stem, then a little up the stem itself to add a little more bulk?

 

[mtb101]

Thanks for all the tips guys, exactly what i wanted.

I think ill clean around the valve hole and the valve stem first, if that still fails can try new tape.

For those who mentioned plumbers tape, did you just wrap it just above the black rubber base of the stem, then a little up the stem itself to add a little more bulk?

I wrap it from base of stem up, aim is to make stem a pretty tight fit in rim hole, then tighten valve up, I use pliers, although don't need to do that on a ust rim. My tyres only lose 5 psi over 2/3 weeks.

 

[BM Epic]

Another option is putting grease on the rubber block that seals to the rim, the grease will swell the rubber thus giving you a better seal, did this myself and worked perfectly every time, the grease stayed on for the life of the tyre also, the valve stems are still perfect after 3 years!

 

[sidetrack]

I use grease as well

 

[BMCFatboy]

Tightening etc will help but then you're in all sorts of trouble if you have a flat on trail and need to remove the valve to get a tube in. Cut a piece of tube say 2cm x 1cm then cut a very small hole in the middle then push your valve through it before you push it through the rim. This will create the seal you need.

 

[mittagongmtb]

Yes - don't overtighten as you will find that all you do is 1) make it very difficult to hand-finger unscrew on trail or 2) end up pullling the valve stem through the half way through the rim and create a big problem (speaking from experience....)

Best check your rim strip first!