After many attempts at sealing a rim with tape I have given up. I just cannot stop a leak around the valve. I am 99% sure that there is a tiny nick in the valve hole inside the rim and the rubber taper of the valve won’t seal it. Sealant doesn’t either which is strange. Anyway I was wondering if the rim tapes with built in valve might solve this. After all the nick will now be under the sealant tape which will be keeping air away from all holes.
Tried a bit of inner tube around the valve base, heat shrink to increase the thickness of the valve seat, lots of tape, no tape , everything to no avail.
Bright ideas anyone?

What rim/tape/valve/sealant are you using?

Sliced BMX tube.

Pacenti rim, tried Joes and Stans sealant, Stans and other valves.
Gorilla, insulation and duct tape. Tried them all.
WTB Cross Boss tyres pops on perfectly with track pump. Takes air to 70psi and seems good but goes down slowly. Bath test shows leak from by valve and I am darn sure that the air is not escaping under that tape then moving through the rim to the easiest way out.
Thought about BMX tube but wrote them all off as Schrader only. Must look harder.

Decathlon usually have cheap presta bmx tubes 20″ and 24″ on the shelf. Cores aren’t removable though if that matters to you.

Tubeless ‘cross-you’re on your own-hated it & could never get it reliable!
I gave up & bought tubs for racing & stick with tubes for playing.

BMX tube then I reckon. Need to solve it as the rims will get another set of tyres in the summer and become my rough stuff ones with tubeless tyres.

Maybe a 26″ tube sliced for 700c.

Never tried cross tyres/rims but ghetto always works for me on any rim/tyre I try. At higher pressures it might need a standard rimstrip too though.

Try 24″ on 700c reckon 26″ might be baggy.

I run slit bmx tube strips on 26″MTB

Really reliable tubeless.

Disclaimer not tried on skinny cx tyres … If you die it isn’t my fault. 😛

24″ inner tube and has held 65 psi for 24 hours. Yeah!
I am using the inner wide enough to fit between the bead and the rim. is this OK or should I trim it to fit between the rim walls?
I am damn sure that I don’t need to increase the seal there just around the valve.
I somehow feel that all would be more secure with no tube between the bead and rim.

I had that

I got an old inner tube, cut a small circularish bit out of that, put a hole in the middle of it and used it as a ‘washer’ between the valve and rim strip, worked for me

Been there and it failed hence the whole inner tube bit

Isn’t there a proper rim strip? They tend to be much better than DIY bobbins ime.

Bath test shows leak from by valve and I am darn sure that the air is not escaping under that tape then moving through the rim to the easiest way out.

What makes you so sure of this? I’m not sure how you’d tell the difference. I ask only because I’m surprised that the rubber on the valve could leave a hole so big that sealant wouldn’t get it.

Tubeless ‘cross-you’re on your own-hated it & could never get it reliable!

What problems were you seeing?

You’re quite clear that you’ve tried everything you can think of and used all sorts of different tapes.

I’m having a hard time believing they all fail, since they mostly work for pretty much everybody in most circumstances.

I can therefore only conclude that you’re doing something fundamentally wrong and you’ve not spotted it.

Have you tried going back to first principles and being careful and methodical?

Must admit to only retaping 5 times. Gorilla x 4 and duct x 2. Identical procedure, valves, tape etc on 3 other Pacenti rims. All went up with track pump easily and stay up. This one has a small nick in the hole. Valve does not fill that nick no matter how tight or slack it is. They are all a bit firm. 3 types of valves, a pair of each.
Damn sure that the tape is sealing the spoke holes. Spotless rim each time. Not a single bubble from any spoke hole.
It looks as if the rubber on the valve is a bit firm and when pulled into the hole on its taper does not” expand” or not compress where the nick is.
Inner tube with attached valve work perfectly. If it would work as just a tape ( like a Stans strip)it would be perfect.