Hex Wrench for Tire Valve Caps

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Here are two wrenches for Tire Valve Caps. One is sized to fit a hex cap that is 9.5 mm across the flats. The other is for a cap that is 12 mm across the flats. Chances are good you will need a size that isn't here, but you can scale one of them to meet your needs. If you adjust the size, start with the one that is closest to your cap dimensions. Scaling it down will also reduce the wall thickness and weaken the wrench. Update 3/12/18 I added a version of the larger wrench that has a wider (more comfortable) handle. I needed this because I have caps that have a seal that is not resilient, and they require a higher torque to ensure it does not leak. update 11/11/17 replaced larger wrench with one with modified handle and corrected spelling. Why bother with something like this? In places where a schrader valve is used (tires, Air conditioning, etc.) The cap IS the primary seal, not the schrader valve. The valve just prevents the gas from rushing out while the cap is put in place and provides an inexpensive means of injecting gas into the item. Schrader valves can be notoriously leaky over their life. If this makes sense to you, you may want to check the caps and seals on your home and auto AC compressors; they are very inexpensive and service techs don't have an incentive to check them (you will be back sooner if the gas needs to be added). AC pressures easily run 10X that of an auto tire, and the gas is more expensive! Keeping tires properly inflated increases their life and your gas mileage. A small wrench allows you to apply enough torque to ensure that the cap is seated well. Depending upon the sealing material, you might be able to apply enough 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 good seal.