How ChronoTrack B-Tags Work

It may look like a normal racing bib, but your race may depend on its hidden technology.
Gary John Norman/The Image Bank/Getty Images

Who wins in a foot race? Back in the old days, it was a fairly cut-and-dry affair. That guy who ran fast enough to spear an elk through the ribs with a sharpened stick? He won. And that guy with the limp who wound up in the belly of a saber-tooth cat? You guessed it: He came in dead last.

Today's runners are different animals, however. Those ancient, ferocious felines are extinct, so instead we run from the ravages of a sedentary lifestyle and pursue that worry-free taste of clarity that comes with physical exertion.


But hey, all that healthy, new-age crap aside, we still want to know how we rank. Did we breach the top 10 percent in last weekend's 10K? What exactly were our splits? Did we at least beat out that jerk from work with the toe shoes?

Since major running events typically attract hundreds and thousands of runners, organizers have to depend on something other than pen, paper and a stopwatch to clock everyone's time. The 1990s saw the rise of personal timing devices, usually affixed to each runner's shoelaces, and the technology continues to evolve, increasing the speed and reliability of race results with each new design.

The ChronoTrack Systems D-Tag is just such a shoelace tracking gizmo -- and the slip of sticky paper that slides around your lace works much like the smart chips that keep you from shoplifting clothes at the mall. Remember that My Little Pony T-shirt you fleetingly thought about stuffing in your bag? If you'd gone through with the plan, the smart tag would have set off an alarm when you passed between the sensors at the entrance to the store.

Both security smart chips and the D-Tag system depend on UHF radio-frequency identification (RFID) technology. During the course of the race, runners trample over special timing mats that contain antennas that receive the signal from each individual runner's tag. This allows the system to track hundreds, or even thousands, of competing runners and their individual RFID tags.

Now ChronoTrack Systems has another product on the market: the B-Tag. Fear not, barefoot runners! This number doesn't go on your laces, and your wrists and arms remain free for your normal selection of watches, heart-rate monitors and MP3 players. You wear this little number right on your chest.


All Up on Your 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?


Author's Note

Senior Staff Writer Robert Lamb
HowStuffWorks 2009

At this point in my life, I haven't really given running a proper go. I've always been more of a swimmer and, more recently, a yoga enthusiast. But a number of my HowStuffWorks co-workers are passionate runners, so I can see the appeal. They run in packs – sometimes from zombies, sometimes dressed as Disney princesses – and they always return home with a story or two.

Maybe I'll get into running eventually, but until that time I'm waiting for ChronoTrack to develop a RFID system that evaluates my hand positions during down dog and corrects me when my pigeon pose isn't optimal. Y-tag, anyone?


Related Articles


  • Guy, Sandra. "How the Chicago Marathon chips track runners." Chicago Sun Times. Oct. 6, 2011. (June 14, 2012)
  • Pique, Stephane. "The Truth About RFID Read Rates." RFiD Journal. May 7, 2012. (June 21, 2012)
  • "Timing Through Time." The Pacific Northwest Inlander. May 2, 2012. (June 14, 2012)