Ok about 3 months ago I had a nail in the back tire, got it replaced. I haven't gotten to ride much since then because of work maybe 100 miles or less. Came home from work and noticed the back tire was flat. Figured this was due to colder weather. Aired up the tire and heard the air immediately coming back out of the valve, with good pace I might add. Opinions on what could be the problem here?

Thanks.

 

The valve core may just need to be tightened a little. They're removed to deflate the old tire and usually left out to get the bead to seat on the new tire. The installer may not have tightened it quite enough.

 

Thanks, can I tighten that up with a valve removal tool? Also is it righty tighty on the valve core?

 

Ok after further inspection the entire valve was very loose and the nut was also very loose. I managed to tighten the nut with a pair of needle nose plyers to the best of my ability but it is so tight that I could get a crescent or socket wrench on it. Is there a special socket made for that tight area on the rim? Seems the leaked is fixed for now....there may be a slow leake now though will check pressure over the next few days.

 

What I would do is to fully remove the valve core (yes, valve removal tools often have that little key on a tip) and closely inspect. One can't exclude having collected by accident a sand grain in the seating, or the seating being damaged from a previous event like that. If in doubt, simply replace.

Your initial description with the air coming right out of the valve does sound like a defective valve core.

Suspected blow-by from a loose valve stem/nut on a tubeless rim would come from the valve stem base.

 

Had the same problem a few years ago on a FXR turned out to be a small tear in the tube itself where the valve went into it, going by a post I read a year or so ago its a fairly common problem with inner tubes.

 

you can get some spray 409 or similar type of foamy soap and spray the valve stem and the hole where the valve goes in the valve stem and look for bubbles (leaks) ..if it is leaking it will be obvious...if it is leaking around the base of the valve stem (where it attaches to the rim the tire needs to come off and the tube replaced, if it bubbles at he end of the valve stem where the air goes in the tire you will need to replace the valve itself..pretty much any autoparts store will have them for cheap...or go take one out of your neighbors bicycle when he is not looking...