Sealant eventually finds its way into valve cores, clogging the mechanism and making inflation frustrating or impossible. Replacing the core restores full function without swapping the entire valve stem—a faster fix that keeps your existing tubeless setup intact. Stan's NoTubes designed these replacement Presta valve cores to fit their removable-core valve stems and most standard Presta valves across the industry, giving you a universal solution for valve maintenance regardless of which brand built your wheels.

The cores thread directly into Stan's brass and alloy valve stems, maintaining the airtight seal that tubeless systems require. When sealant accumulates inside a valve and airflow becomes restricted, pull the old core with a valve core tool, clean any residue from the stem threads, and install a fresh core. The process takes seconds and eliminates the need to break down tire beads, disturb existing tape jobs, or replace otherwise functional valve hardware. For valves that have been clogged repeatedly, cleaning alone sometimes isn't enough—dried sealant can damage the internal seal surfaces, making replacement the more reliable long-term solution.

Keeping spare cores on hand makes sense for anyone running tubeless across multiple bikes. Cores fail gradually as sealant deposits build up, and having replacements available means you're not stuck with a slow-filling tire before a ride. Sold individually, you can stock up on exactly what you need for your fleet without buying more than necessary.