Presta to Schrader valve adapter.

The adapters I found on Thingiverse either leaked air, or they were too thin and broke after using twice. So here is an improved version.

Features:

• easily reaches 10 bars (148 psi) for racing tires.
• excellent seal with the pump chuck (since no external thread is used that leaks air).
• extra-long stem to prevent the chuck pin from pushing against the valve tip (no hassle with air escaping as you connect the pump).
• virtually unbreakable.

Information on different valve types and names:

• Presta valve, also called Sclaverand valve or French valve. The valve type with the smallest diameter, therefore used on performance bicycle with small rims.
• Schrader valve, also called American valve is used on almost every motor vehicle worldwide.
• Dunlop valve, also called English valve. Uses the same thread (5V2) like Presta.

The valve threads follow a special norm, the ISO 4570. Details: http://www.iso.org/standard/30078.html and http://mdmetric.com/tech/thddat26.htm

Presta valves details:

• The external threads at the tip of Presta valves are 5V2, measures 5.2 mm diameter and 1.058 mm pitch.
• The external threads on the main body of Presta valves are 6V1, measures 6 mm diameter and 0.80 mm pitch.
• As the valve is closed with the screw, a cap on the valve is not mandatory.

Schrader valves details:

• The external threads on the main body of Schrader valves are 8V1, measures 7.7 mm diameter and 0.794 mm pitch.
• The air chuck must depress the spring-loaded pin in order to inflate the tire.
• A cap has to be used to prevent dirt from entering the valve.

Valve /// ISO 4570 /// Diameter x Pitch
Presta tip /// 5V2 /// 5.2 × 1.058 mm
Presta stem /// 6V1 //// 6.0 × 0.80 mm
Schrader /// 8V1 /// 7.7 × 0.794 mm.