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Is there a point at which the spoke bed becomes too narrow for valves to seal?
Most of my 30mm+ Mtb rims pop the tyre and stay up.
My road / gravel rims and now latest xc wheels on the other hand…getting the valves to seal seems nigh on impossible.
I’ve tried tesa tape, gorilla tape, muc-off tape, small valve holes, big valve holes, messy valve holes, tidy perfect valve holes, tight valve collar, loose valve collar and just cant get the valve to seal.
And no logic to it. One wheel of the pair inevitably goes up and stays up. The other relentlessly goes flacid after a couple of hours.
Today, i tried something different. Had some mastic left over from my van repair so wrapped that around the valve stem and squished it down around the valve area but jeezzz……all the continual pumping up tures i’m getting arms like a gorilla!
****in tubeless.
#1 - get an old school style tube patch (*thick rubber style), pierce/drill in middle and use it as a seal.
#2 - #1 plus a small dab of silicone sealant.
Good luck
I just use a tiny square of now redundant inner tube as a "washer" on the odd occasion there's a valve seat issue. Probably once in the last 8 years?
You can get different rubber grommets that fit your inner rim profile better if you want to throw some money at it. Muc-off do a range
I’ve used a patch of inner tube successfully in the past too.
Also make sure it’s definitely the valve itself not sealing, I was doing my mates wheels with him a couple of weeks ago and we thought it was the valve but it was a bad tape job letting the air in through the spoke holes and it was coming out at the valve.
+1 for the tape.
The valve hole is the easiest place for sealant that's got into the cavity to escape from so it looks like the valves are at fault when it's actually the tape, seen this a few times at the shops I've worked at.
In instances where the valve hole was a bit loose for the valve, a few additional 5 inch strips of rim tape to add layers to that section work well if you don't have an old inner tube to cut up.
I used to tubeless my Mavic 521 rims which were about 21mm wide
I used the old Joes strip (I think it was Joes - the rubber one with built in valve) to great effect with awkward wheels previously.
Seems to have vanished from the market although this below looks similar, and not badly priced really.
https://www.merlincycles.com/effetto-caffelatex-mtb-tubeless-strips-99080.html
Tis definitely valve. I’ve re taped umpteen times and there’s never any sealant under the tape. But plenty of sealant between the valve stem and the valve rubber.
Ironically the block valve rubber seals worse than the round despite the deep square ish spoke bed.
Also tried the inner tube patch. Was better but still no cigar.
So far so good with the mastic. No air bubbles in the bath and still holding pressure. It shouldnt be this much faff!
I dread taking tyres off. Didnt want to this time but warranty replacement on them so couldnt pass that up!
Piece of inner tube - failed
Mastic - failed after sealant top up
All tapes - failed
Finally 3 strips of gorilla tape over the hole seems to be working.
Thinking about it. I’ve only had this issue after switching from Orange Seal. I used to hear the hiss the. It stopped after sloshing it round the valve.
Stand, muc-off, peaty’s and now Magic Milk. All failing to seal the valve.
Kind of confirms my unofficial theory that sealant is a clever marketing scam. It certainly doesnt seal anything more than a thorn out on the trail. Not until you leave it to cure overnight anyway.
For my road bike I've gone back to tubes. Life is too short.
Indeed. I’m 90% towards joining you. Just the pitch black cold wet puncture on my 18ml commute puts me off. Plug n go with tubeless.
I tighten up the valve VERY tight which stops it. Guessing tighter than recommended but I use pliers to tighten which squeezes the bung on end of valve as much as it can into the hole. This is on narrow road rimes
For my road bike I’ve gone back to tubes. Life is too short.
Same here, it worked quite on low pressure wide tyres for winter but is such a ball ache changing tyres it's not worth it.
Ive just resorted to using inner tube sealant for one of my tyres, it was always a lightweight tyre that didnt have a good shape, but has maybe got old enough to develop middle age sag.
Too many puncture hazards to just use tubes.
For my road bike I’ve gone back to tubes. Life is too short.
+3 for this. Never seems worth it to me.
Interesting the 700c road wheelson my gravel bike are tubed after wasting days on them. Again it was valves not seating. My off road wheels are fine tubeless
hatter
Full Member
+1 for the tape.The valve hole is the easiest place for sealant that’s got into the cavity to escape from so it looks like the valves are at fault when it’s actually the tape, seen this a few times at the shops I’ve worked at.
+! this, it's almost always the tape (except he meant "air that's got into the cavity", not "sealant)
It's curious how different folk's experiences differ. Getting on for 15 years tubeless on mtb here, about 4 on gravel and a short period on road (albeit not on <30mm tyres) and this isn't an issue I've experienced. I've had valves need tightening and broken a couple, and had tape fail a few times, but not much more than that. I wonder whether you've got a component somewhere that isn't right. Tried different valves? Are you using enough sealant that it goes and fills all the little holes on initial inflation? I use a fair bit on new parts especially, and sometimes find it loses a lot of pressure until things bed in after the first ride.
I also do the valve collar up pretty tight, by pushing down quite hard on valve from the tyre side while I do it up. That's proved necessary sometimes.
Depends on the valve/rim?
I've got a set of shimano wheels that will not seal with anything other than the OEM valves. Everything else is fine with some degree of faff.
Pressing it into the rim with my thumb then nipping up the locknut seems to work better than trying to pull it through.