Tubeless Problems

theunmarkableb

Hi guys
I have a 2010 Specialized Epic Comp that I have been trying to convert to tubeless. I was assured that the tires and rims are tubeless ready and the rims came with the blue Specialized tape inside, unfortunately too many winter rides had eaten away at the adhesive on the blue tape and so I replaced it with the Stans No Tubes yellow tape which seems to have done the job. I’m using some Stans valves that I got from a local bike shop (they are copper looking with a larger round rubber section for inside the rim, I think they might be an older model) and the front wheel sealed almost instantly and has maintained it’s air pressure for several days with no drama what so ever, the problem is that no matter what I do, the rear leaks air from the valve straight away and it seems impossible to seal, I’ve put soapy water all over it and there is no air escaping from anywhere other than the valve, I tried a different kind of tubeless valve and had the same result. Any ideas what else I can try? Could there be a problem with the rim? I haven’t tried re tapeing it yet….. Could there be something wrong with the tape around the valve hole?

Any help would be greatly appreciated, I’m sooo ready to be free of tubes.

CraigXXL

Put another layer of tape over the valve hole and create a small hole so that the valve itself makes the hole the correct size. Make sure the rubber bung on the valve doesn't have any high spots from the mould, fine sand paper will remove any burrs.

theunmarkableb

Thanks I'll give that a go and let you know how it goes.

MattJWL

CraigXXL wrote:

Put another layer of tape over the valve hole and create a small hole so that the valve itself makes the hole the correct size. Make sure the rubber bung on the valve doesn't have any high spots from the mould, fine sand paper will remove any burrs.

This, plus make sure there's no burrs on the inside of the hole.

Paradoxically, on my old/spare rear (Mavic Crosstrail) which isn't supposed to be TL ready, I had to file the outside (ie. tyre side) valve hole to be a little bigger, as I wasn't getting enough airflow through to seal the tyre, although I'm guessing you just need to fettle a bit. Make sure the valve is nice & tightly done up, and that you've got enough sealant in there.

cheers
m