Continental Tubes - valve core unthreading?

[Ozz]

Anyone else have a problem with conti tubes, and the valve core unthreading when unscrewing pump head after inflation?

I'd never had this issue with any tube previously, until a couple years ago with some MTB tubes...weird and annoying. Put some new tubes in my road bike tires a month ago or so....same thing started happening.

I use a Lezyne alloy pump with a screw on pump head...works well, just have this issue with conti tubes....

Anyone found a solution other than screwing it back in and tightening?

[Steve in SLO]

This is a known issue with Lezyne pumps. I haven’t heard anything pacifically about Conti tubes.

[Ozz]

Originally Posted by Steve in SLO

This is a known issue with Lezyne pumps. I haven’t heard anything pacifically about Conti tubes.

Interesting.....I do have a Hiro pump head on my Xmas list...maybe that will help!

[AngryScientist]

yea, this is an old issue. i find that if i just take a pliers and torque the valve core in there tight, it's not an issue. you could do a drop of blue locktite too, but just cranking them down good once usually stops this from happening.

[avalonracing]

Originally Posted by Steve in SLO

This is a known issue with Lezyne pumps. I haven’t heard anything pacifically about Conti tubes.

Yup, my Lezyne pump seems to remove cores like it is its second job.

[Steve in SLO]

Originally Posted by Ozz

Interesting.....I do have a Hiro pump head on my Xmas list...maybe that will help!

That’s what I did and worth every penny.

[Veloo]

Don't recall if my tube was Conti but it happened to me so I started to torque down the valves when I bought them and I also carry some kind of valve tool in my saddle bag now. They're pretty small and don't take up much space.

[Blue Jays]

As mentioned by AngryScientist above, my technique is just to crank them really tight with pliers.
The amount of torque exerted with a pair of pliers far exceeds what unthreading a Lezyne pump will do.

[Mark McM]

Due to the more positive connection, I actually prefer screw-on pump chucks. I've only had my Lezyne screw-on chuck unscrew the valve (on any brand tube) 2 or 3 times in the past 10 years or more. This is just a minor annoyance, since the valve can be easily screwed back into the stem. Due to the common usage of valve extenders, I keep one of the small valve tools (that come with most extenders) in my saddle bag anyway, so even out on the road I can screw a valve back in.

[Ozz]

Thanks all.....was just wondering if it was just me....sounds like may be the screw on pump head. I only have conti and michelin tubes....the michelins don't have removable cores, so probably why I blamed conti.

I like the screw on head too....had an old Silca Chuck until I got the Lezyne about 10 yrs ago. I went thru a coupe rubber gaskets a year with that old head. The Lezyne screw on just works...no leaks, easy on off....until it removes a valve core.

I do have a Stans valve tool I picked up a few months back. Works so much better than pliers (right tool for the job and all that). I may need to get another one to carry with me.

[caneye]

I have a lezyne pump and have had similar issues when using conti tubes.

good thing is .. most multi-tools come with a valve core remover that you can use to tighten said core. Or keep a cheapo valve core remover like this:

https://www.chainreactioncycles.com/.../rp-prod155551

[Mike Bryant]

My experience with any new removable presta valve tube it to go ahead and snug them up. Many times I’ve chased leak downs to find a loose valve core seeping out air. Occasionally even the core itself leaking; in which case I grab an old presta core I’ve saved from an old tube and throw it in there. Usually just cut or pull the whole presta valve off an old tube and stash it for later.


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[jimoots]

Use the bleed valve on a lezyne head to avoid unthreading removable cores.

And yes snugging them up at the start also helps.

[RoosterCogset]

Originally Posted by jimmy-moots

Use the bleed valve on a lezyne head to avoid unthreading removable cores.
.

I'm not picturing this. How does using the bleed valve do anything aside from letting air out of the tire?

[Mark McM]

Originally Posted by RoosterCogset

I'm not picturing this. How does using the bleed valve do anything aside from letting air out of the tire?

The bleed valve on a presta chuck doesn't let out of the tire. It lets air out of the hose (the presta valve keeps air from escaping the tire). Releasing the pressure in the hose/chuck reduces the force (and friction) between the chuck and valve, which reduces the torque on the valve when you unscrew the chuck.