What are those yellow things below the left chainstay?

[Jupe]

On every bike I've seen in the Tour this year there is a yellow thing below the left chainstay. Does anybody know what those are? Thanks.

[55/Rad]

Accordng to the guys at cyclingnews.com - it is a transponder used to automate the timing and check who is in which group at the finish.

55/Rad

[Smoothie104]

It used to be on the fork leg near the dropout.

[aluckyfiji]

So what happens if you have to change bikes during the stage?
do you get the time of the team car when it crosses the finish line? j/k

[zonatandem]

It used to be on the fork leg near the dropout.

That is a transponder for the electronic timing devices now being used in many events. Beats the old stopwatch and a lot more accurate!

[Jupe]

Thanks everybody. I kinda thought it might be something like that.

[khuon]

So what happens if you have to change bikes during the stage?
do you get the time of the team car when it crosses the finish line? j/k

Wouldn't that really suck as I don't think the team cars get to cross the finish line? They have to pull off prior or hang out at the back.

[rygreen]

I've used a similar thing at some triathlons where I've competed. You wear the chip on a velcro strap that goes around your ankle. It registers the times as you go across pads while coming into and going out of the transition area (and across the finish line.) So, post race time and splits are available almost immediately.

[itschris]

I use a chip as in my tri's but I'm not sure if that's what it is. The only reason I question the responses is because it doesn't look like all the riders have them, not even in the top teams... and I've noticed once on stage 2 I believe, then they changed the bike out, neither bike had one, but the rider ahead, not a GC contender did have one.

[Gurgus]

I'm glad someone asked about this, I was going to ask the same question about these little yellow thingies. Thanks Bikeforums!

[Tony Miller]

Great guesses but we all know they are miniature motors developed by NASA to power the bikes. Jeez, you don't think those guy can really ride at that pace for 23 day do you!

Tony