Continental Tubes - valve core unthreading?

[Ozz]

Originally Posted by jimmy-moots

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

And yes snugging them up at the start also helps.

Unfortunately, my pump has the Original Flip Chuck, and no pressure relief....

Article linked actually talks of unscrewing valve cores as one of reasons for redesign of the chuck head, and including a bleed valve.

[RoosterCogset]

Originally Posted by Mark McM

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.

Ahh. The pump style where the pump valve is not depressed. Doh! One reason I've had no interest in that style of floor pump, though my on-bike minipump works that way. Seems limited utility to build a bleed valve into a pump head solely for purpose of releasing the hose pressure, but maybe this valve core unscrewing thing demanded this feature?

[Mark McM]

Originally Posted by RoosterCogset

Ahh. The pump style where the pump valve is not depressed. Doh! One reason I've had no interest in that style of floor pump, though my on-bike minipump works that way. Seems limited utility to build a bleed valve into a pump head solely for purpose of releasing the hose pressure, but maybe this valve core unscrewing thing demanded this feature?

Lezyne ABS checks are reversible, for use with either presta or shrader valves. When used with shrader valves, the tube valve is held open, and the bleed valve reduces pressure in both the hose and the tire. When used with presta valves, the tube valve is free to close on its own, and the bleed valve reduces pressure in only the hose, making it easier to remove without the tube valve unscrewing.

[muz]

I have more than a handful Lezyne pumps, they are my favorite. The solution to the valve unthreading is extremely simple and obvious. Unthread the hose from the pump first, which releases the pressure. I do this with the earlier pumps that don't have bleed valves.

[jimoots]

Originally Posted by RoosterCogset

Ahh. The pump style where the pump valve is not depressed. Doh! One reason I've had no interest in that style of floor pump, though my on-bike minipump works that way. Seems limited utility to build a bleed valve into a pump head solely for purpose of releasing the hose pressure, but maybe this valve core unscrewing thing demanded this feature?

It's not a valve for fine tuning pressure, but it does have a couple of purposes (at least that I've identified)

1. Removes pressure on the core so you can unscrew the chuck without unscrewing the valve core

2. Allows the valve to reseal, so when you unscrew the chuck you do not suffer a pressure drop which can sometimes happen.

[shrimp123]

three possible solutions (in order i use them)

1. carry a schrader adapter and flip the hand pump head. benefit : i have a place to store the adapter in case there is a gas station nearby

2. tighten the valve core with pliers and release pressure with that black button. works most times, but, have had some failures

3. curse a few times and use 2 flat stones to tighten them on the road and repeat 2.


what i have observed (yeah right!) is that it has trouble only when i am in a hurry and/or someone is with me waiting to give me advice.

S