Complaint about replaceable Presta Valves
 

I’ve had bikes with Presta valves for at least 30 years. In the last year, two bikes (one new, one just with new tubes), started getting flats, sometimes slow, sometimes fast. I was never able to find any holes. After a few wasted tubes, I figured out I was loosening (or completely removing) the valve while opening or taking off the cap. I didn’t even know this was possible. Have Presta valves always been removable or is this a new thing? Why would I want to replace a Presta valve? Anyway, I’m loctiting them when I think about it. I’ll let you know how that goes.

Do NOT LocTite them. They're replaceable because people damage/break them or they get clogged w/ sealant. Don't overthink this, just check them every now and then. If it were that big of a problem there would be tons of people complaining about it.

I had a removable presta valve shoot passed my head when I went to pump up my tire. That'll jump start your morning.

When I worked as a car mechanic learned to turn my face away from the tire while seating or inflating it, and to keep clear when removing valve caps, after such wake-ups.

Don't tighten the top cap down so much. Just get it snug. The air pressure in the tire keeps it closed, the screw is redundancy. If you really tighten the top cap down, you're more likely to loosen the valve stem when you go to open it. Also, screw on pump heads are garbage for a similar reason.

Another option...Throw the cap in the trash. They aren't really necessary.

Checking the presta valve tightness is part of prepping the new tube before installing. You failed to do this.

Rule #60

Some of the plastic caps I have had recently for my Woods/Dunlop valves have tended to undo the retainer as I have attempted to just remove the cap.

Of course I would never loctite my Woods valves in because that would prevent me from easily releasing the air, and I keep the caps on to keep the crud from blocking the valves - but if you use Presta valves and never have to remove them then why not loctite them in, but I do worry that it might not solve your problem.

While some may think the plastic caps are not needed I think a bicycle that goes in for a tune up or flat repair should come out with caps as this shows the mechanic pays attention to such details. Some customers would be upset if their bike came back from service without caps.

I've had a few tubes that leaked around the replaceable presta valve and no matter how tight I made it they would still leak very slowly. So, one small dot of blue Loctite on the threads to seal it and all was good.

A dab of liquid electrical tape works well too & will allow for the valve to be easily removed in the event that the tube needs to be serviced.

+1. This is kind of a rarely talked about thing but I always tighten my presta valves when new. I learned the hard way when fixing a flat on the road with my screw on pump and unscrewed the valve removing the hose. I found out my chain tools' rectangular cutout fit the presta valve flats perfectly. This was the only time I've ever used that chain tool for anything. Check yours if you carry one as they are not all the same and may not work. Some spoke wrenches also work, not for DT nipples and some others but I can't remember which size works. They also make these little gems to carry with you and cheap. Origin8 Presta Valve Core Remover Tool - Blue Sky Cycling Your bike shop may have them too. I should add that since I've started checking the valve tightness when new I haven't had one come loose again. Just don't get carried away with gorilla strength. A light snugging up will do.

I’ve kind of wondered why the Presta valve core is removable to begin with (although not all Presta valve cores are removable). And of course some Schrader cores are removable too. Why? Price-wise, and the trouble...it seems like just replacing the tube would be more prudent if there is a valve problem. On a big car or truck tire...I can see that replacing the valve core would be easier than dismounting and remounting the tire. But with a bicycle tire/tube...what’s the purpose?

Dan

+1 I had Lezyne "Road Drive" mini-pumps on two bikes for a while. They were small, light, efficient and had a separate hose to protect the valve stem. However, they also had screw on valve heads and efficiently removed the valve core from some tubes when the head was removed. After a couple of frustrating roadside flat repair attempts I gave up on them.

I've seen plenty of presta valves get mangled up by ham fisted pump operators. Easy to just replace the valve which you won't have to buy if you save a couple from tubes that get thrown away. For bikes I think it's just the industry standard to make replaceable valves for Shrader and the bike tube mfr. would probably have to spec their own non-replaceable valve increasing the cost and as with the presta having a couple of old valves on hand is much easier/cheaper than tossing a tube with just a bad valve.

I would prefer a shop not to add things to my bike, unless I specifically ask for it. Even something as small as a valve cap. That said, there aren't many things I need a shop to do that I can't do myself.

Take a stab at how I know you haven't read every post in this thread...



Hint: #2

Get some michelin airstop or aircomps.. none of that worthless threading all down the valve stem, nor removable valves.

I buy only tubes with replaceable valves so that I do not need to toss a tube because of a bad valve. The rubber in the gasket that seals the valve is actually thin and fragile and go bad before the tube goes. Unfortunately the replaceable cores in Schwalbe tubes, made in Vietnam, tended to be recently bad right out of the package - that could be an alternative explanation, instead of the unscrewed cores, for the leaking in the original post. I have better quality cores in standby as a matter of principle, just like spare tubes or bolts :D.

I leave the caps on just to annoy people.

I learned to deflate the tire before removing the presta valve like most of us the hard way....in this case it shot the valve and my nice new indulgent park valve tool flying, lucky I did not take and eye out. and I had to completely clean the shop to find the tool

though the little plastic jobbies wrenches that come with sealant work, the metal park valve tools is so nice

I fit those thin valve retaining rings as well, for the same reason.

I search for Continental tubes BECAUSE they have the replaceable Presta valves and I can inject sealant. My Michelin and Vittoria tubes do not have replaceable valves. Most of my mid-range sewups also have replaceable valves, useful to me for the same reason, to add sealant.

Also sew-ups are generally available with one length stem and require extensions and removable valve cores to use effectively with deep rims.