Hello,
I started this post thinking I had the answer...I had a whole paragraph typed up. Then I realized, "that doesn't make sense" I always figured it worked by noticing differences in tire rotation...when the tire gets low on air, the diameter changes..the sensors pick up the difference in rotation. But, after pondering a bit, I said..wait, the circumference doesn't change, so the rotation should remain the same. So...This is a great question. Hope someone has an answer. This whole BB is getting really slow.
Later now,