Adding sealant to tubeless tires usually means breaking the bead, pouring in the liquid, and hoping most of it ends up inside the tire rather than on your floor. The Park Tool TSI-1 eliminates that process entirely by injecting sealant directly through the valve core opening. You remove the valve core, thread the injector onto the valve stem, and squeeze the plunger—sealant goes straight into the tire without dismounting anything or making a mess.

The injector body holds up to 60ml of sealant, which covers most road and gravel tires in a single fill and handles mountain bike tires with one refill. Clear markings on the barrel let you measure exact amounts rather than guessing, which matters when you're trying to hit a specific sealant volume for your tire size. The Presta valve adapter threads directly onto the stem, creating a seal that keeps sealant from leaking back out during injection.

This tool earns its spot in the kit during sealant top-offs. Tubeless sealant dries out over time—most manufacturers recommend refreshing it every three to six months depending on climate and riding frequency. Without an injector, that maintenance task means breaking beads twice a year per wheel. With the TSI-1, you remove the valve core, inject fresh sealant, reinstall the core, and spin the wheel to distribute. The whole process takes about two minutes per tire.... Read More