I have always been a bit sniffy when people complain about tubeless having used it for 15 or so years but I have met my match. Cannot get a new wheel to stay up. Tyre pops on the rim fine but all pressure is lost through the valve hole. I have been through 4 different valves with no result, even tried retaping the rim but no good.
Any suggestions before I resort to tubes which makes buying lighter wheels pointless?
There's not really any kind of mystical reason for it failing.
It's going to be your taping job or the valve.
Give us your set up.
It'll be the tape.
I agree. What tape? How many wraps? Wrap 'pattern'?
It will be taping, possibly rim joint.
We have resorted to:
- uber cleaning of the rim. Like spotless. Then clean again. And again.
- using a few mm of extra tape to cover rim joint almost into sidewall of rim, allowing tyre to seal last few mm with the bead.
- using hair dryer on hot to warm the rim, tape on radiator, and then working really fussily to get the tape to stick - two wraps of course.
The tyre then worked a dream and wheel is fine a couple of years later.
As Matt says above. I recall on one rim I smeared a little epoxy resin/sealant into the remaining bit of rim seam that could be seen up the side, to be sure.
Sometimes a sacrificial rubber washer is required on the valve, but, I have found that some variations of rim & valve just don't work well.
The rim came ready taped with what looks like Tesla with a single wrap. I will try a new double wrap with the Tesla roll in my spares box and resort to epoxy if all else fails.
Tried muckoff valves with the various rubber seals?
Assuming you've used tape that is wider than the internal rim measurement then you only have two potential leak spots;
(a) The tape overlap. I prefer to have this opposite the valve, to leave only one layer for the valve to seal. Getting the overlap stuck down well is the key. Make it a decent length, make sure the non-sticky side of the tape is clean, maybe install a tube for 24 hours to get a good seal.
(b) The valve hole. I cut this with a scalpel and make sure the tape edges are fit to the hole, with no folds or rough bits. All you need is a good seal between the rubber bung at the base of the valve and the rim tape.
possibly rim joint.
Had one like that with Halo Vapour 50 rim. Ended up with split inner tube ghetto version, that works perfect.
Actually when I'm thinking about it, I have never had any issues with ghetto, but several instances of problems/fails with proper stuff xD
Cheers!
I.
Nothing I can add that hasn't be said. It will be tape or rim joint.
What makes you sure its the valve hole? If the air is escaping from the valve where the lockring is that could be a leak anywhere in the rim, the valve is the easiest escape point. Nipples provide a surprisingly air tight seal.
Nothing I can add that hasn’t be said. It will be tape or rim joint.
And if the tape is wide enough then it won't be the rim joint (which is why the ghetto, split-tube works)
Having just gone through similar, it seems that a new valve (Rimpact MTB) has done the job. It has lost a very small amount of air, but all my tyres do as they live in a warm house. If you haven't had any luck with valves, I'd say it is the tape.
My tape was 30mm on a 29mm internal width rim. There were plenty of very small air pockets (in the dip of the rim were it is curved) but it seems to have bonded really well. I overlapped by about 6 inches and started opposite the valve hole.
won’t be the rim joint
It was rim joint in my case me thinks. Tried several different tapes, including extra wide one, that went all way up to rim bead and above. It was always leaking on the rim joint.
I even tried epoxy rim joint. Made it slightly better but it was still leaking.
Tested it in bathtube.
Cheers!
I.
@Ivanmtb I agree, +1 for ghetto tubeless with a split BMX tube. If it’s good enough for Jared Graves, it’s good enough for me, and he’s been running it for years.
Hangs head in shame, I had a valve leak and fixed it by using an old style rubber patch (with a hole thru it for the valve) and some bathroom waterproof sealant between the patch and the rim …..
I was going to mention sealing between the valve & rim. Since ages ago, I learned (on here I believe) to add a smear of grease around the valve seat when assembling it first time.
Having done loads of tubeless setups using this technique, I can say it works, has no ill effect (no grease reacting with sealant etc) and always lasts the lifetime of the tyre.
I guess the grease seals micro leaks between valve & rim. Whatever, it works.
I was pilloried on here for being adamant about buying"old fashioned" solid rim bed UST wheels.
#groupthink
I assume that you have got sealant in the tyre . If so what brand ?
I'm liking the idea of greasing the valve rubber the first time, lets the rubber slip in further to conform to the hole I guess.
Enough innuendos for one post methinks.
How long would you expect a tubeless tyre to hold it’s pressure before needing a top up?
Hallelujah! Finally managed to get it done.
It took a careful retape a la Scotroutes, Muckoff valves and being left with sealant for a couple of days.
I always assume wheel builders are better at taping than me but this wasn't the case!