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I've been fighting with a set of Clement X'Plor Ush 700x35 tyres for a week now. They appear to leak from the rubber around the bead, but not from the bead itself. It looks like, for some reason, the rubber just isn't sealing. There's 120ml of Stan's in there and the tyres are pumped up to the minimum pressure on the sidewall (55psi) as per the instructions on the Stans.
The rim strip is electrical tape, which I've used successfully in the past. The wheels are FSA NS 700c wheels which came with rim tape that just pissed air out. The valves are the FSA ones.
The rear tyre went down to 10psi after an hour and a half this morning, but sometimes it'll drop to 20psi after 7 hours. The front tyre is a bit more consistent, generally dropping to 20psi after 7 hours.
Here's the valves-
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And here's what my tyres look like in water. This is the rear, the front also does it but less badly. They only start streaming like this once they reach 55psi, it's quite sudden. Before that there's no obvious evidence of leaking.
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The valve also does this underwater-
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What can I do to sort this? My next stops were adding shit loads (say 250ml) of Stan's and pumping up to 80psi to force it into the rubber (this was recommended by Tyre Yoghurt- my plan is to remove the Stan's once it's made the tyre airtight then replace it with Tyre Yoghurt as it never dries out) or, as a last resort painting the inside of the tyre with rubber cement.
1) If there's sealant\air leaking out from the base of the value then most likely you rim tape isn't sealed properly. I've never had any luck with electrical tape, I use Gorilla duct tape.
2) Air \ sealant leaking out from the side of the tyres would indicate that it didn't seat properly. Did you hear the two loud cracks when inflating indicating the beads sitting in to the rim ?
Soapy water between the tyre and rim to help the bead sit and pump up as high as 80 psi or until you've heard it pop on to the rim. Do this outside and wear ear plugs because the mess and noise if it blows off the rim is unbelievable.
Of course, maybe it's just a bad rim \ tyre combo ?
+1 for what feed says. Also, sometimes unseating one side, soaping the rim and then reseating can help - then repeat for the other side
feed - the beads are definitely seated, they've banged into place and I've had them up to 80psi. It's leaking out of the rubber itself I think. If you look really carefully at the first pictuer you can see that the bubbles start a few mm past the edge of the rim.
I've got a roll of Gorilla tape, I'll put a layer of that on. I suspect the electrical tape isn't deep or squashy enough for the rubber on the valve to settle into.