Hex Wrench for Tire Valve Caps

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Here are two wrenches for Tire Valve Caps that fit different sizes of hex caps. One wrench is designed for caps with a diameter of 9.5 mm across the flats, while the other is for caps with a diameter of 12 mm across the flats. If you need a wrench that fits a cap size not listed here, you can scale one of these wrenches to meet your needs. However, it's best to start with the wrench that is closest to your cap dimensions, as scaling down will reduce the wall thickness and weaken the tool. I recently added a new version of the larger wrench with a wider handle. I created this design because I have caps with non-resilient seals that require higher torque to ensure they don't leak. In areas where Schrader valves are used, such as tires and air conditioning systems, the cap is actually the primary seal, not the valve itself. The valve simply prevents gas from escaping while the cap is being installed and provides an inexpensive way to add gas to the system. Unfortunately, Schrader valves can be prone to leaks over time. If this makes sense to you, I recommend checking the caps and seals on your home and auto AC compressors, as they are relatively inexpensive and service technicians often don't have a reason to inspect them. AC pressures can reach 10 times those of an auto tire, and the gas is much more expensive! A small wrench allows you to apply enough torque to ensure the cap is seated properly. Depending on the sealing material, you may be able to apply sufficient torque with your bare hands. If your metal caps don't have a sealing ring, their only function will be to keep dust from entering the valve stem. Adding an O-Ring inside the cap provides a secure seal. I hope this information helps you choose the right wrench for your needs!