They have teeth spaced to engage every link of the chain as it passes over.
The designers are still cutting weight everywhere they can, reinforcing critical junctions like the bottom bracket.
Carpenter-Phinney then "threw" her bike forward and won the gold medal by less than than half a wheel, becoming the first female Olympic cycling champion.
What kind of bikes do you ride in track cycling? Our full range of Track Cycling Sprockets can be found.