What was that yellow thing hanging down from the chain stay that seemed to wrap the bottom of the chain. The camerman kept focusing on it but the commentators never took the que and explained what it was.
it’s a timing chip transponder thingy. so when they go through time check station thingys, they can tell how far ahead the break is, etc.
Timing and GPS-device.
That isn’t a dumb question at all consdiering one “expert” TV commentator already described that device as Campagnolo’s new electronic shifting battery comparment. Oops.
well gooooolly!
HA! sounded good at the time.
Timing and GPS-device.
No, it’s not a GPS device, it’s a transponder to record times.
why don’t they use a little chip like in a tri race?
Because it doesn’t have to stay with the athlete through a swim and run, so it can just stay on the bike.
why don’t they use a little chip like in a tri race?
That is all that it is. No GPS. Just like an ankle chip in a tri. We use the exact same one for our road races around here as well. Go across a matt with wires = time.
There are a couple different styles of timing chips that they have for road racing. The race I did this morning, you just mounted on the axel of the front wheel. In the Tour, the reason it’s o the chain stay of the bike is that with wheel changes for flats, if it were on the axel nobody’d have a chip.
I ran across this website that claims to have a Google/TdF mashup. Don’t know how the whole scheme works, but seems like the little transponder thingy is part of the equation.
http://www.ubilabs.net/tourdefrance/
Later,
Carlos
But why the big giant thing? Why can’t it be some tiny thing like a tri race type chip that just goes on your stem or handlebar. Does the tdf model read other stuff like cadence or wheel revolutions?
well, when you are crossing the line in a sprint at 40+ mph, with 50 cyclicsts separated by fractions of seconds, perhaps the sensor needs to be “bigger” than running across at 12 mph? I 'dunno - but that is the EXACT same thing I was putting on my bike at road races - complete with the “extra” small zip tie on the back of it to hold it/battery together. Same color as well. And, if memory serves, if the top 2 zip ties aren’t tight - it can get sidways and make a nice rattling sound in your spokes 
Not very aero either. Think of the half second you lost in that race. 
The camerman kept focusing on it …
Which was kind of odd in itself. Of all the pagentry of the TdF, an ugly RFID chip is the least noteworthy thing.
Transponder, not chip- that’s why it has the battery.