Presta removable core

taximan

Vetus bumbolum iuvenum corde
I had a visit from the 'P' fairy the other day, so I fit a new tube, inflated it and when I tried to remove the pump connector the valve core came out too. This is the first time I have come across a presta valve with a removable core. Can anyone tell me how to keep the core in place after pumping up the tyre or is it a secret.

488739


 

Venod

Eh up
I have had this happen, a small adjustable on the two flats of the valve core and tighten usualy cures it, I think you can buy a special tool to fit also, I cut a suitable groove in the square bit of metal that goes through the door inbetween the handles.
 
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Ajax Bay

Veteran
Location
East Devon
Using a pump that doesn't have a screw-on connecter also minimises the chances of the core unscrewing. Or take care to buy tubes which don't have a removable core. Or if a new tube has a removeable core, use just a tiny drop of threadlocker and tighten it before putting in it in your back pocket. This assumes that the rider is not a 'slime in the tube' type, nor are they one who needs a valve extension to cope with deep section carbon wheels.
 
Quite easy and cheap to get a tool for either Presta or Woods/maybe some Schrader type valves. They sometimes come with extra valve cores. A good idea, because they can go bad. Especially the Presta, the little brass center of the core can get bent.
 

wonderloaf

Über Member
Location
Hampshire
This happens a lot. If you haven’t got one of little plastic deelies or an ‘official’ tube core tool, use a spoke key, or the spoke key that comes on a lot of bike multi tool chain breakers. I use press on mini pumps, and press on CO2 inflators, just to be safe.

https://www.decathlon.co.uk/co2-pump-20g-cartridge-id_8502292.html
Like these.
I had one of these inflators, whilst being very handy make sure you don't loose the O-ring or seal inside the nozzle (as I did) as it renders it completely useless. Very inconvenient whilst fixing a puncture in the back end of nowhere, so glad I also carry a mini-pump with me!
 

DRHysted

Veteran
Location
New Forest
I feel slightly less embarrassed about the time I pulled my valve core out now.
it happened after a puncture on the way to work after I had inflated the tube using my Co2 pump. The pump froze slightly to the valve core, and as I was removing the pump the core came with it, resulting in a suddenly flat tyre. Thankfully I always carry 3 Co2 cylinders, so after some swearing I was on my way quickly.
I’ve also experienced trying to inflate a tyre with the rubber seal missing from a Co2 pump. Most of the gas escaped to atmosphere, but (just about) enough got into the tube for me to limp to work.
 
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