the ideal xmas gift

[vorsprung]

for the cyclist that already has everything

https://www.cyclingweekly.com/news/product-news/can-buy-ultra-efficient-chain-used-britains-olympic-team-not-cheap-400017

[Cudzoziemiec]

It's cheaper than I thought. I know a bloke who was in an engineering team at Bristol Uni working with them. They have to stand a huge amount of torque apparently, comparable to that produced by a medium sized car engine.