Somewhat related, does anyone have experience using the valve stem cover pressure monitors? Not the fancy ones, just the kind that replace the existing valve stem cover. You can buy them set to monitor a specific tire pressure. Instead of checking with a gauge which I am sure most of us always do before hitting the road you just visually and quickly check the valve stem cover color. Normally if a tire is correctly inflated, it shows a green color; if it goes below that pressure by 4 pounds it show green and yellow, and if under-inflated by eight pounds or more, it shows green, yellow, and red.
They aren't very expensive.
http://www.accupressurecaps.com/s.nl...&category=4113