Mystery tubeless le...
 

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[Closed] Mystery tubeless leak - what should I look for?

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Vittoria Terreno rear tyre, possibly coming to the end of it's life as sidewall threads are starting to come through (testament to lack of clearance at chainstays I think) and top of tyre worn smooth.

Riding on Friday after a long fast and rocky (by gravel standards) descent, tyre was obviously losing pressure, but no sealant or obvious hiss present.

Eventually gave up topping it up with pump and stuck a tube in, assuming sealant had dried up, but lo and behold, plenty of sealant still splashing about inside!

Can only assume a puncture in a location where sealant wasn't reaching, suggest something at the bead?

Haven't had a chance to look at it so just trying to narrow down the search before an evrning of cursing in the garage 😁


 
Posted : 30/08/2021 9:29 am
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Could be the valve if sealant isn't doing its job, might just be a loose core. Spraying soapy water on a well inflated tyre can help find the source of a leak.


 
Posted : 30/08/2021 10:05 am
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I'd suggest checking the valve core too (and the valve body in the rim), had them gum-up a few times on me, pump up the night before, come down in the morning to be greeted by a flat tyre.


 
Posted : 30/08/2021 10:18 am
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The soapy water spray is what I use. Do the tyre and rim, including spoke holes and valve.


 
Posted : 30/08/2021 10:34 am
 aide
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New tyre? It sounds from your description that the old tyre is getting pretty perished if the threads are starting to become visible, may (or may not) be getting to much for the sealant to handle


 
Posted : 30/08/2021 1:04 pm
 feed
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Well there are only 4 places that it can be leaking air from, the tyre, the tape, the valve or the rim weld. Big tub of water and immerse the tyre \ rim of the wheel and move around until you see the escaping air bubbles.


 
Posted : 30/08/2021 1:22 pm
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Fast rocky descent… low pressure, big impact = dented rim?

As above, tub of soapy water will find it. Either way, sounds like you need a new tyre 🙂


 
Posted : 30/08/2021 1:30 pm
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D'oh, pinch flat at the bead ☹

Is it worth trying to patch? Feel sure I'd read of people struggling to fix holes at the bead due to flex.

Did wonder about making a patch from an old latex tube, just not sure if it would stick to the (butyl?) inner surface of tyre...


 
Posted : 03/09/2021 5:17 pm
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I wouldn’t bother to try to patch it as you’ve already said the tyre is on its way out due to the sidewalls, etc. Unless you are away from home and unable to get a replacement.


 
Posted : 03/09/2021 5:46 pm
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By far the easiest way to find a leak is take wheel out & dunk it in the bath. Instant result.


 
Posted : 03/09/2021 5:48 pm
 kcal
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like a sticking plaster on a joint really, too much hassle though I guess it might work as stop-gap (or when you find out how much new tyres cost).

My least favourite tubeless leak was only found when fully immersed said wheel in a big area of water (wheelbarrow..) and noticed the leak was from between two raised letters (it was a Spesh tyre) on the sidewall. new tyre, but old stock from closing LBS so I assume had sat for donkeys folded up, and had flexed too much. Did get it sorted with a plug or a patch, and was good to go.


 
Posted : 03/09/2021 5:53 pm
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Pinch flat at the bead is how I seem to kill all my tubeless gravel/cross tyres. Cross bikes are not mountain bikes but sometimes I forget when I'm enjoying myself ☺️


 
Posted : 04/09/2021 9:40 am
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@13thfloormonk

Definitely doable with a plug, not a patch, this one evaded me for a bit, just kept leaking slowly until I found it, popped a plug in and has been fine since:

Once pumped up and under pressure the plug should deform against the rim.


 
Posted : 04/09/2021 10:52 am

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