How ChronoTrack B-Tags Work

All Up on Your Bib

A very special princess B-Tagged racing bib
A very special princess B-Tagged racing bib
Elizabeth Johnston/HowStuffWorks

Granted, it's not the best of news for you guys who like to run bare-chested and glistening across the finish line, but the ChronoTrack B-Tag is actually a part of the racing bib. On the front, your bib appears quite normal. Oh look, there's the number you wear on your chest. There's your name and race number on the front, along with the emergency contact number someone calls if you collapse after a few miles on the back.

Look again at the back of that bib, however and you'll find two B-Tag stickers that contain the RFID antennas that communicate your position as you cross the timing mats throughout the race -- especially at the finish line. Of course, your larger marathons feature runners in the tens of thousands. Even with high read-rates of 99.8 percent and above, some runners remain skeptical [source: Pique].

Here are a couple of things to keep in mind, though: Since those strips are vital to officially recording your race time, you'll want to avoid bending, breaking, folding or chewing it (even when you hit the wall around mile 16). Also, don't hang any metal near it -- the safety pins attaching it to your technical T-shirt don't count -- or you may distort the signal. And don't cover it either.

Once the race is over, however, you can trash the disposable and recyclable B-Tag. So there's no call to worry over lost-tag fees and no hapless volunteer bending over your stinky foot to retrieve a chip after your sensational victory (or crushing defeat).

But if you lose your B-Tag before the race is over, you might as well have dropped out halfway to enter a hotdog-eating contest. You simply won't register as having finished without it, so don't lose it, runner!

If you're looking to host a race of your own, you'll want to hire a race timing and results service -- and many of them now use the B-Tag system. ChronoTrack systems provide these hosting companies with far more than a few boxes of sensors. It isn't the only player in the race-timing game, however. Companies such as Innovative Timing Systems and RFID Race Timing Systems offer competing systems that also depend on bib/chip systems.

The overall ChronoTrack system offers real-time, online, mobile and social media capabilities as well. So even if you're coming in last place, you can always check your smartphone to see which B-tagged goody two-shoes won the race.

But hey, it beats winding up in the belly of that saber-tooth cat, right?