Noticed the stem was crooked, so bent it back to center and SNAP off it came. Amazingly the tire didn’t deflate or lose air. Since am on vacation no spare valve stems/cores so rode it 8 miles to a LB which helped me out. Took a couple of people to figure out how to get the remaining piece out. Since the tire is tubeless, some of the goo in the valve stem was holding the remaining piece in place. When home, I will remove the stem, clean it out and be good to go. Haven’t ever had this happen in 40 odd years.

Ooof, unlucky. That's a stroke of luck that you were able to still ride it to the bike shop for assistance.

I've snapped one valve stem before. Some heavy-handed removal of my disc wheel "crack pipe" pump adaptor snapped the stem in half. Instant deflation. I was not impressed with my own incompetence... 😅

As long as the tire retains air pressure, snapping off the external part of the valve inner core is not a big deal. Just keep the tire pumped up.

I have bent them many times, but never had one snap off. I’m planning to try those new Scwalbe Clik valves when they become available later this year. They are a direct replacement for Presta cores.

One thing I found is that pumping the tires with the valve at the very top of the wheel helps prevent breaks. When you take the pump off the valve you knock it straight down and are much less likely to bend the stem while doing so.

I've always been under the impression that the length of the ''pin'' increases over time of pumping and pumping. Is it just in my head or is it what's actually going on?

Sometimes mines will bent a little, but I've never snapped one.

That's just in your head.

The part of the pin that people see, with the little barrel nut on it, is just there to prevent you from accidentally pushing it down and releasing air when the barrel nut is tightened down. It doesn't actually seal anything. In a Presta valve nothing holds the valve closed except the pressure in the tire (on a brand new tube, the valve isn't held in the closed position until you put enough pressure in the tire to press it against the opening and it seals.)

I had one snap off recently on my commuter, when topping off the tire at work. I rode home, it was fine. I was able to deflate the tire later by pressing down the core with a pen.

The metal is pretty brittle; bent in one direction is bad, bent back is worse.

Done that a few times and, at least once, left it snapped off until I had to change the tube.

Dude.... Never try to bend it back. They always break.

+1 Leave 'em bent. Eventually you are putting in a new one anyways. Bent ones work just fine.

One of the extras I always have on hand is a spare Presta core, including when on tour. Also, ensure that tubeless valves have replaceable cores some cheap ones do not. 12 packs of cores are available on AliExpress for $5.00 or less.

I used to bend those things often when I was using a "push on" pump head on a frame pump.

I switched to screw-on style and haven't messed up one since.

+2. I did it with tubes a couple of times before I learned my lesson.

My problem with those is when the core is not tight, which seems to be a feature of Vittoria tubes, and after pumping up the tire, as I unscrew the pump head, it takes the valve core with it.

"It's only a LITTLE bend. I'll just straighten.... Oh, hell."

Will carry a spare in the future.

Yep. That’s exactly how it went.

Been there, done that, have the valve-core-less tubes.

All of the last 10 or so comments just prove my point. Put the pump head on with the valve facing straight down and when taking it off just punch it down, not to the side, not up.

1st rule of fighting bent stems is to not talk about fighting bent stems.

seems ya have a plan in action.

Talking about being bent or twisted, here you are. Like a fly to honey.

This may be irrelevant, but some time ago I started experiments with how far out I really need to open a presta valve. Being an LBS wrench with alotto bikes, I inflate alotto tubes. I’ve found that only one turn (two half turns) is quite adequate. Plenty of air flow and much less valve stem sticking up to get bent. Works for me. I’ve not bent a core stem.

I've had a bent stem on one of mine going on three years now. I'd say I've taken a "if it ain't broke don't fix it" approach to it. But I guess the truth is it is just almost broke so if I try to fix it it will be broke.

This is something I’ve always wondered about, but for some reason I feel compelled to fully open them. But now I’m finally going to try your one turn method!