Most vehicle applications use a valve stem within the size range of 1.25 inches to 2 inches. High-pressure valve stems are designed for steel wheels which you will regularly see if you’re drilling in car tires. For other stem valve types, you may need to use a different drill bit size. I am only basing this on what the stem valve is commonly used for. Not everyone owns a trailer or a large truck that has a different bit size compared to regular cars.