Recently had a problem getting enough air into my tubeless tyres to get them on the seats before fully inflating. Never had an issue in the past, and even when just topping up there’s a lot of back pressure in the pump.

Now I’m pretty sure this is becase the valve cores, (presta) are all gummed up with sealant. Do any of you lot replace the valves or cores regularly? Can I buy a big bag of cores off that there internet?

Can’t you just clean them? I clean mine whenever I change tyres/top up the sealant

Never replaced nor had them clog up how are you adding the sealant through the core?

Can’t you just clean them? I clean mine whenever I change tyres/top up the sealant

This. I find it really satisfying when you get a big lump of dried latex out of it.

Unscrew the knurled brass bit all the way and you can drop the core of the valve core out, so you can clean it properly. Takes seconds.

Any Schwalbe tube has removable cores, so a double bonus if you carry a tube, there is a spare core there for you as well. Mavic plastic valve core tools are great for the toolkit and weigh nothing.

Bit difficult to clean presta cores, they have a little spindle and seat inside a tiny tube so difficult to get in. I put the sealant straight into the tyre, I suspect its the small amount of that gets spurted out when inflating that are drying up and causing the issue.

Probably neither are such a great problem for Schraeder valves.

edit

Unscrew the knurled brass bit all the way

Hmm, think mine have the sindle a bit flared at the end to stop the nubbin coming off, but I’ll have a look.

Bit difficult to clean presta cores, they have a little spindle and seat inside a tiny tube so difficult to get in.

That’s why you can remove them – just unscrew the bit you unscrew (if you know what I mean) all the way, then you can drop the spindle out and clean them up.

Theres a little how to on the Stans site if you’re having a technical issue removing the core.

I can remove the core no problem. It’s removing the core from the core I’ve not cottoned onto yet! 😀