My front tire popped while I was inflating it and I had to buy a new one. Today I replaced it and filled it up, so I decided to refill the back tire too. I let all of the air out to start pumping it up again, but when I started I could hear the valve letting out all the air I was pumping in when I was about half way done. It was fine this whole time, am I going to have to replace this tube now too? I JUST WANT TO RIDE MY BIKE

Is the valve core tightened?

I wonder why you let all the air out.

I just top mine up.

are you using an air compressor to fill your tires?

I just double checked and everything seems to be in order.

I let it all out because for some reason when I've tried to top it I can't seem to get any air in. It just works better for me lol

No air compressor here, just a floor pump.

do you use a presta to shrader valve adapter? and what type of pump? .. You answered that you have a floor pump.

Hmm. I wonder if it's something like pressing very hard on the presta valve while the tube is empty and the valve stem bottoms out on the rim and has a chance to put a slice/cut/hole where the valve meets the tube.

Yes I do use an adapter, and I have a Schwinn floor pump that has worked great for me until just right now.
Also, I know for a fact it is coming out of the valve area itself, not out of a hole/cut/slice in the tube.

I often have to play with my pump and attach the head a few times before I get a proper air flow, otherwise it will like jam and no air goes in, or its too lose and all the air escapes, I have to try a few times to get the head on just right. its also a lot more like this on the road bike side than the MTB side as there seems to be a bigger tolerance for getting it right so many try this with your pump?

although this is a known issue with my cheap floor pump and has been mentioned in reviews but person ly apart from this I find my pump is awso,e!

also I let some air out of the tires before I pump up just to clear the valvles of any possible blockages as if had a tire blow up I'm my face so I don't take any risk these days! don't let the tore all the way down though as it will be hard to get the pump on as bad Been said.

Next time I get a floor pump I will spend more to get a better one over all but more so a much better head that just works when I attach KT to the vulve.

I have a Joe sport blow two if anyone's interested its bright yellow!

also r u sure the vukve is straight through the rim hole and not going through at an angle as its very easy to do this and can chase problems with pumping up and even lead to puncture.and don't worry of air comes out as you pump up as so long as most of it stays in a tiny bit coming out is fine as mine dose that to but still pump up quickly to my desired pressure.

I would surmise that the presta valve adapter which has a rubber o-ring on it may be the culprit. I found them to be half useless and enjoyed my floor pump upgrade to a pump that works on both schrader and presta valves. If your pump hose is removable you may be able to simply buy a new hose with air chuck and continue using your regular pump.

Perhaps the oring on the adapter is failing which means pieces that air can get by the stem and leak out as you add air. I guess it would leak more as you were on the up stroke and then quit the leak as you were on the down stroke of the floor pump. Also there is a chance that due to using the adapter the presta valve is actually being pressed in by the adapter which can happen easily enough. I only used an adapter for about a week before deciding that it was way more of a pain than it's worth.

If your adapter doesn't unseat the presta valve stem automatically, it can stick and prevent air going in. Don't empty the tire; just depress the valve stem quickly to unstick it. Then top off the tire.

just made a SIG, sorry for the post please Ignore it as I'm just testing it, as it has not showed up on my above posts.

You might need to 'bump' the valve when you place the chuck so the pump pressure can overcome the tire pressure.

Hmmm... I've been using presta valves for about 38 years and can't ever recall any pump head or adapter that "unseats the presta valve stem automatically". I always have to depress the valve to break it's seal before pumping up a tire. Any depressing of the valve stem, that you mention, would have to be automatic and momentary, or air wouldn't stay in the tube.

Could you enlighten me?

I'm going to blame the adapter in this instance.

I have an old pump and adapter that I keep at work just in case I need it when I commute. It drives me insane. I usually have to tighten it to the extreme and then hold the nozzle just so while I pump with the other hand in order for any air to go into the tire. I usually end up letting most of the air out before I can get any air to go in. It's awful. It also doesn't help that sometimes the presta valves stick and need a little extra force to get that first pump of air in them.

I'd highly recommend a new floor pump with a head for presta and schrader valves. I have the Topeak Joe Blow 2 at home, its cheap, built well, and easy enough to top of the tires in the morning with just a few quick pumps. Honestly, go drop the $20-$30 on a new floor pump and your arms, upper body, and tires will thank you!

I'm going to blame the user. Nothing personal. I bet it's just inexperience.

I don't know, pumping tires isn't rocket science. Like I said, I have similar experiences at work with a 15 year old floor pump and an adapter.

Giyo GF-12 pump has a universal Presta/Schrader head that depresses the valve stem automatically for Presta the same way it would for Schrader valves. A bit annoying since it leaks air until you lock the head on, but handy for getting the exact pressure you want and no worries about sticky stems.

I used an adapter with a 1969 vintage schwinn pump for about a year, then got a Silca pump head that worked with the Schwinn pump head. I was glad when the adapter era was over.

I haven't heard of that before, but now, I won't be shocked if I see one in the future.

The valve that you twist to loosen and tighten to "tighten, at the end of the presta stem comes out and may be loose, taking it out and applying a drop of oil will assure a good seating between it and the metal stem. I'm unclear that you know about the valve stem, and it's ability to loosen, it could be tight, and of course, no air could go by.

Sure, my "Hurricane" brand pump head actually depresses the valve stem when you lock it on, so freeing up the valve stem beforehand isn't necessary. As Fiery said, you have to lock the head on quickly to not lose much air. If I were using a Schrader valve with an adapter, it is unlikely that this would take place. That could be why you have never seen it. But as I said before, just quickly punching the valve stem inward very quickly sets it free. After that the pump pressure at the bottom of the stroke is enough to keep open it up on each stroke.

Being a hard core Silca pump user has protected me from modern pump advancements!

Surely you don't mean a Silca frame-mount pump. I never could get one of those to even half fill a tire. I always thought they were supposed to be painted the color of your frame and just mounted on it for decoration. Seriously, that's fine for a tube change on the road, but at home you should really be using a good floor pump. They are not expensive and will change your life. How many things can you say that about?