Tour De France 2018

Who can explain that massive jockey wheel to me?

Marketing.

Search for ‘ceramic speed’ on youtube. Claim to save x-amount of watts over standard equipment. But as @Tijs says, it is basically just marketing.

EDIT: Chava’s ride is just generally hot af. 10/10 would bang.

Who can explain that massive jockey wheel to me?

Chain wraps at a less severe angle which in theory saves a bit of wattage.

But yeah if you need them your team or sponsor buys them for you.

2.5W