I found the source of the slow leak in my front Tre. The tube itself is fine but the valve leaks air unless it's screwed in very tightly. Tightened up the valve and everything seems to be in working order. Should I replace it anyway? This is the first time I've encountered this type of problem so I guess I've been lucky.

Anyone else dealt with this problem?

Is this a replaceable core? If so, try a different valve core.

No, standard tube. Can't say I've ever noticed this problem before.

Could be dirt got into your valve so it doesn't seal properly

You didn't say if it is a Schrader valve (like on a car) or Presta (the skinnier ones). Schrader valves are removable (with a cheap tool) and cost about $.50 each - good deal cheaper than a new tube.

Some Presta valves are replaceable, not all, and they cost about $1.50 each - starting to get closer to the price of a new tube.

Personally, if I have a valve leaking I just replace the entire tube. It always seems like the new valve stops the leak but not long after I get a leak around the base of the rubber where the valve stem goes into the tube.

I was born with a leaky valve. Had to have it replaced when I was 25. Cost a lot more than a new tube.

If you are not now, start using valve caps. I know this amounts to heresy on this forum, but..

A new tube is around $8, I'd just replace it.

Hmm, did not know some presta valves were replaceable. Then again, I've never had a valve go bad. I think I just got a bad batch of tubes. I bought a bunch on sale from nashbar for $2 apiece. Now I know why they were $2 apiece.

I always use valve caps. I think they're a good idea.

Some presta valve cores are replaceable... some are not.

Look for two flats on the threads just below the top. I'm pretty sure that if you have a replaceable core, then they are pretty universal.

With more, better sealants, hopefully we'll see replaceable cores becoming more common.\

There are special tools to remove them, but I just use a standard adjustable wrench.

I use the valve caps that have the little (Schrader) valve remover tool built into them. I think I've only used those once in my whole life, but it's nice to have right there if you need it. Get them at any auto parts store.

how do you remove a valve stem Core with an adjustable wrench,,,

If you've leak tested it in water, not sure why you wouldn't just use it. At worst, it will start leaking slowly again. Assuming you carry some way to refill it on the road, it's not going to leave you stranded.

If you use sealant in your tubes, a removable core makes it easier to inject the sealant, and if/when the sealant clogs the valve, you simply remove it and soak in ammonia to dissolve the sealant. I find it handy to have a few core available, so I can swap a clean one in while letting the clogged one soak. You can buy cores separately or in bulk, or even salvage them for free from discarded tubes.

Attach to the two flats. Turn counter clockwise. Be careful of the spokes.

A turn or two, and you can usually get it the rest of the way out/in with the fingers.

Note, this is for PRESTA as above.

For Schrader, you'll need the tool, or a valve cap with the tool.

I see,,,,,said the blind man....

as he pee'd into the wind. "It's alI coming back to me now".
Jon