Who manufactures presta valved tubes with removable cores?

The question is in the title: who manufactures presta valved tubes with removable cores?

I sat down at my computer with the very intent of asking this question! Not Michelin latex, not BBB, I can inform. I'll be pleased to know the answer, and where you can order them.

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"All that we see and seem is but a dream, within a dream..."

I thought they would all be removeable but on closer inspection of my selection of tubes non of them are? Why would you want to remove them?

Being old, and infirm, I have shaky hands. In the middle of a race a few days ago I got a flat, and it being a race the hands were even shakier. So I was in the wonderful position of having fixed the puncture, put the tire back on, inflated it, then finally snapped the nut off the top of the valve. Scooped some mud up in the valve cap and managed to finish, as I didn't need that much pressure, it was a fantastically muddy course after all. Yet would have been nice if I could have just swapped the valve core, and I've had to throw an otherwise perfectly good tube away. LBS's being what they are nowadays, they don't sell that size tube, so have to wait for them mail-order. If I'm going for mail order anyways, I think I'll get exactly what I want. Yet none of the sites I've visited list presta tubes with the information as to whether they have removable valves, although many do sell spare cores. Asking the sites is generally pointless, they just reply with the exact same blurb you can read on the site. So I thought I'd ask the gathered congregation for their thoughts, comments, and miscellaneous personal abuse.

All my Contis have removable cores.

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Cheers,
George.

One also needs replaceable cores for some deep rims, so that certain types of valve extenders can be installed (other than the black aluminum style that simply screw onto the end of the valve).

Good shout.

Have now got myself a pack of 5 on order and a couple of spare cores.

All the online shops seem to stock them.

Thanks, George.

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"All that we see and seem is but a dream, within a dream..."

Way to go for the UK postal strike! Ordered, like, yesterday. Courier has literally just arrived! Now I'm in Denmark, ordered from an on-line outfit in the UK who said 'sorry for the strike, we'll be using a courier'. Yeah, thinks I, it like normally takes a good week or so for stuff to appear so spare me the flannel.