Tubeless question

[RustyMTB]

I'm taping up a rim for a new tire. It may be me, may be the wheel, a Race Face AR30 offset 29 but I repeatedly have the same problem setting these up. I get air leaks at the valve. This is usually a taping problem or a valve install error. Usually with fettling I can get it to seal but today it's proving a real problem.

I have tried tightening & loosening the valve, using a little grease on the valve bung & even double taping the valve hole. Open to advice but wonder if anyone has had success not taping the valve hole at all? It seems to me that the valve seated directly onto the rim should in theory seal fine but I've never done it that way.

 

[Zimmerframe]

I normally end up with doubled tape at the valve .. but on some tricky ones (like that with a concave shape at the valve point) I've resorted to even using an extra washer or o-ring to get a seal. Will depend on your valve/bung to a degree.

 

[RustyMTB]

Yes, I'm using Muc Off valves which helpfully come with various shaped bungs but find on this wheel the offset leaves a gap on the external side. It is tedious as the only way to test is to mount & seat the tire.

 

[Shjay]

What width rim tape are you using? Have same wheels 1st time had issues air was escaping as must have moved tape when seating tyre. No issues since but make hole in tape with pick then 2mm Allen key then the valve, if not careful can make hole too big & air escapes. Have decent lezyne digital pump that can dump 130+ psi into tyre to seat it

 

[RustyMTB]

Got it now, retaped & it went up first go. Currently undergoing rigorous leak detection in my advanced wheel research facility.

 

[steve_sordy]

I have at least a double thickness of rim tape over the valve hole. I then pierce the valve hole rather than cut a hole. I wrap a few layers of ptfe tape (also known as plumber's tape) around the valve seat (belt & braces, I know).

Along with the sealant in the tyre, I've never had a problem (yet).

 

[Wilbur]

Aside from using a valve suited to the rim profile (I find Stans round valves are less compatible with more rims these days); I use a soldering iron with a round tip to make a perfect hole in the tape which helps with sealing quite a bit.