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Tubeless tyre loses seal with rim, fix?
Wycombewheeler:
I've been running tubeless for a while now and my frequency of issues by the roadside is well down but I have had the following occur a few times on rides (about once/year) and can't work out what the fix is.
Occasionally, I will hit a pot hole and the tyre will shift on the rim creating a leak between the tyre and rim. The rim is not dented, but the tyre which had previously sealed will no longer hold air. No amount of sloshing sealant around at the critical area seems to resolve this. Removing the tyre and refitting will resolve the issue, but this is a job to be done at home with a proper pump.
Has anyone else experienced this?
Obviously not hitting potholes is ideal, but following other riders, riding in the dark, riding through puddles can lead to the occasional incident.
Is this a flaw with the hookless rims beloved of the wheel manufacturers to save a few pounds at manufacture? (i.e. the bead going up against the rim hook would be far more likely to seal?
Is there a way of fixing this in the field? Obviously I can resolve the issue with an inner tube, but this requires great care in ensuring the tyre is free from sharps. Is it a case of more pressure (perhaps with CO2?) or more patience with the sealant at a low pressure?
robgul:
From feedback from customers when I managed an LBS I would suggest this is a common issue - exacerbated by running at low(er) pressure on wide-ish tyres.
Fitting a tubeless tyre and getting it to seat needs quite a bit of pressure, even if the tyre is only partly unseated - IME a pump you carry on a bike is unlikely to cut the mustard - a CO2 might work out on the road.
I have one bike with tubeless (25mm Schwalbe Pro One) and run at pressures as if I had an inner tube . . .
Ian H:
I had that with 25mm tyres, resolved by increasing the pressure from 70 to 80psi.
Other suggestion is to add one or more extra wraps of rim tape to make the tyre a slightly tighter fit.
Hot Flatus:
Never experienced that, but then I tend to run road tyres at almost the same pressure as tubed.
I do have sone 38mm tyres that I run at about 45psi, but no issues yet with burping
Wycombewheeler:
Thanks
helpfully ZIPP 303s have a max pressure of 5 bar (73psi) so I'll try to inflate to 70psi every time, (currently go for 60psi which I find comfortable on 30mm tyres.)
otherwise they will become my off road wheels with wider tyres
--- Quote from: Hot Flatus on 25 March, 2024, 12:01:08 pm ---Never experienced that, but then I tend to run road tyres at almost the same pressure as tubed.
I do have sone 38mm tyres that I run at about 45psi, but no issues yet with burping
--- End quote ---
I do wonder if the pressure inside the inner tube is 90psi (for example) how much less is applied to the tyre because some of the pressure will be resisted by stretching of the inner tube. So is 90psi with no tube equivalent to 90, 85, 80 or 75 with a tube?
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