The valve stem's dust cap is to keep dirt out, not air in. With a tire that is undamaged and properly mounted on the rim, most of the pressure loss comes from air migrating through the rubber sidewall, not through the inflation valve. Nearly all tires lose pressure gradually over time, even if the car isn't driven or the tire isn't mounted on the car. They can also be bulky and typically cost more money, running from $20 to $50. Most dial gauges are easy to read, but models with an extension hose take two hands to operate.
Some dial gauges have more features than pocket-sized gauges-including an extension hose, bleeder valve, dual-scale dial, and shock-resistant dial cover-but we have found that they aren't necessarily more accurate. While batteries can last for years, depending on use, they will run down eventually and need replacement.ĭial gauges have an analog dial, resembling a clock face, with a simple needle to indicate the pressure. On the down side, however, digital gauges are a little bulkier than stick gauges and they require batteries. Some digital readouts light up, making them handy for checking pressure in low-light conditions. They're also more resistant to damage from dust and dirt.
Stick-type gauges, which somewhat resemble a ballpoint pen, are simple, compact, and affordable, but they are a little harder to interpret than most digital gauges.ĭigital gauges have an electronic LCD display, like a pocket calculator, making them easier to read. If you buy online to save money, check shipping charges to see if the purchase is still a bargain. If you need to check pressure in a darkened area, consider a digital gauge with an illuminated display. Buy a gauge with a wide-enough range that it can measure the pressure in a temporary spare, which is typically 60 psi. There are three types of tire-pressure gauges: stick, digital, and dial.