Is this necessary on removable valve cores? Tightening it with valve core tool good enough?

Not necessary.

Uy from qc. Thanks paps.

It is not necessary. However, if you'll ever have to use a threaded CO2 inflator on such a valve, remember that the inflator thread will freeze itself to the core thread during the inflation process. If you attempt to unscrew the inflator immediately afterwards (while it is still frozen), it will often unscrew together with the core and cause instant deflation. This is a rather frequent mistake. To prevent this from happening you have to wait for a certain period of time till the whole thing warms up after inflation. Or use threadlocker on valve core.

Not necessary, and frankly not a good idea. Just torque it down to a couple foot pounds, it has an o-ring.

Tumpak

I don’t use CO2. But thanks for that info, i’ll pass it on to those who do.

Thanks. I just used a spare tube with removable valve for the first time after i got a puncture from a nail. Tightened it just enough. While riding home i had this thought: is there any chance it can unscrew by itself while riding?

Loktite would just make it harder to replace a broken valve stem. I buy all my tubes with removable stems, so I don't ruin a good tire because I screwed up the valve stem. I carry a couple of valve stems salvaged from old tubes in my repair kit that I use on long tours.

P.S. We have been using tubes with removable valve stems for at least 12 years without having a valve stem come lose. We have a fleet of bikes in our family and all of them use Presta valve tubes. We put on a fair amount of mileage. My wife's newest touring bike is 8 years old and has 22,000 miles on it. She has 2 other bikes that she also rides.

About 75% of the Presta tubes we used during this time are represented by the number of valve stem bolts I'e been throwing in my tool box for several years. I just wanted to see how many tubes we use, and they are handy.