Presta Tube Sealant Hack

Modern tire sealants are a gift from the velo gods, drastically reducing punctures and time spent on the side of the trail and road. Where I live, using some kind of flat protection is mandatory both on and off road, for tubed and tubeless alike.

Running sealant inside tubes is highly effective and cheap, but things can get tricky when trying to get sealant into a presta valve. The most obvious solution is to use tubes with removable valve cores, like those from Continental. But sometimes they are out of stock at the shop or you are working on a lady-friend’s bike, and inevitably I end up with a grip of standard core tubes piled up next to the bikes.

My LBS showed me a little hack for getting sealant where it belongs. WARNING: Occasionally this procedure results in abject failure, with the valve/tube ruined. You have been warned.

You will need the following:

—One or more tubes.

—Two pair of needle nose pliers.

—Razor blade or sharp knife.

—Small sealant bottle with applicator top.

—Sealant. I have had great results with both Stan’s and Orange.

Step One:

Photo: Kip Malone

Carefully cut the tip of the sealant bottle so that it can be threaded onto the valve stem. It needs to form a tight seal with the core.

Photo: Kip Malone

Step Two:

Fill small bottle with required amount of sealant. Remember to shake well because the particulates that do the sealing will settle to the bottom. If you don’t shake, they won’t seal. Open the valve completely; if it is a new tube blow just a little air into it so the sealant has somewhere to go.

Step Three:

Photo: Kip Malone

You are going to remove the cap nut from the threaded center rod. With the pliers, careful unscrew the cap nut. It should only be a few stiff turns. Once the nut is removed, push the center rod back into the tube. There is nothing keeping it attached to the valve, use you your other hand to catch and hold it or it will fall into the tube and you will have to work it back up to the valve—no fun.

Photo: Kip Malone

Step Four:

Photo: Kip Malone

Thread the sealant bottle onto the valve stem, invert and empty contents into tube. Remember you are still holding on to the valve rod.

Step Five (The tricky part):

Photo: Kip Malone

Push the valve rod back into the valve stem. You may need to invert the valve body and give it a few gentle taps to get the rod to pop out the top of the body. Use a thumbnail or pliers to hold the rod in place and carefully thread the top cap back on. There will be a couple stiff turns, usually with pliers, and then it should thread down normally and close the valve.

Photo: Kip Malone

Done and done. If it’s a spare tube going into a pack, make sure to put a valve cap on it to keep the valve from abrading the tube. Sealant in tubes last longer than in tubeless tires, so you should be good for a year or more depending on conditions. Remember, many sealants don’t play well with Co2 inflators, so choose your sealant and inflation methods accordingly.