Nobody here has mentioned the climate impact of choosing carbon fiber over steel.

Starling Cycles, a rare producer of steel mountain bikes, concluded that a typical carbon frame uses 16 times more energy than a steel frame.

https://solar.lowtechmagazine.com/2023/02/can-we-make-bicycles-sustainable-again/

Of course, any bicycle will be more sustainable than a car. But we’re in a climate crisis, and that means taking extreme measures, including considering whether even low-impact tools like bicycles could be even more sustainable. We can’t afford to be completely uncritical of any technology.

This is false. Methane is a more potent greenhouse gas than CO2 in the short term, and “natural gas” is just methane. When it leaks, it’s very bad, and could be worse than coal. https://newrepublic.com/article/176605/natural-gas-way-worse-coal