Some Sims don't have a large enough hole around the valve stem to get the head of a pressure gauge to fit well enough to get a reading. Some of the dial gauges with a short hose will fit into these spaces. I purchased valve stem extensions at walmart that extend past the Sims to allow easy access for the gauge. They are inexpensive and replace the caps. The downside is that some people have experienced flat tires, caused by horses pawing and damaging the extensions, causing them to leak. Also if they were buried in mud, it's possible to off seat the valve and end up with a flat tire. I have never had either of these problems. In previous threads, there was a lengthy discussion about older tires. If you click on these threads, http://www.horsetrailerworld.com/forum/thread-view.asp?threadid=9566 you will find instructions on how to determine the age of your tire. There is also a link to the video of the original newscast, which also described how to determine the age of manufacture of the tires. Gard | 
"extendable" tire gauge?
I got out the tire gauge but can't get to the valve stems because of the (I think they are called) simulators. Is there a way to check the air pressure without removing these every time? I've heard of people losing these so I'd rather not be messing with them all the time. Also, where on the tire do I find the year it was manufactured? I need specific directions, please. 
