Tire Valves
Cycling · 9 specs
Direct Answer
Bicycle inner tubes and tubeless systems utilize three primary valve standards: Presta (Sclaverand / French valve; 6 mm stem diameter, manual locknut tip, rated up to 15 bar / 220 psi), Schrader (American / Auto valve; 8 mm stem diameter, spring-loaded central pin, ISO 4570 thread, 0.305"-32 TPI), and Dunlop (Woods / English valve; 8 mm stem diameter, drop-in core).
Source: ISO 4570 (Tyre valve threads) / DIN 7756 / ETRTO Valve Designations · Last reviewed Aug 28, 2026
Specs
| Presta Valve Stem Diameter | 6.0 mm (0.236 in / narrow drilling for narrow road rims) |
| Presta Operating Mechanism | External Threaded Locknut with captive brass plunger pin Manual Lock |
| Presta Maximum Pressure | 15.0 bar (217.5 psi high-pressure road tolerance) |
| Presta Rim Hole Requirement | 6.5 mm (0.256 in diameter hole in rim) |
| Schrader Valve Stem Diameter | 8.0 mm (0.315 in / identical to automotive tire valves) |
| Schrader Thread Specification | 0.305-32 UNEF (ISO 4570 8V1 thread) Standard |
| Schrader Rim Hole Requirement | 8.5 mm (0.335 in diameter hole in rim) |
| Dunlop (Woods) Stem Diameter | 8.0 mm (uses 8.5 mm rim hole, manual rubber sleeve / core) |
| Common Valve Stem Lengths | 32, 40, 48, 60, 80 mm (extended for deep-section carbon aero rims) |
Presta vs. Schrader Engineering & Rim Integrity
- Rim Structural Strength: Narrow aluminum and carbon road rims (15–19 mm internal width) use 6 mm Presta valves to preserve maximum structural integrity across the rim bridge. Drilling an 8 mm Schrader hole into a high-tension carbon rim can critically weaken the spoke bed.
- Tubeless Presta Systems: Modern tubeless Presta valves feature removable valve cores (RVC), allowing liquid tire sealant to be injected directly through the valve stem using a syringe without unseating the tire bead.