system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does a car tire require around 30 - 35 PSI while a road bike tire can require up to 100+ PSI?
gpt
The average car weighs over a ton, not including passengers. Its main purpose is safe and enjoyable comfortable transportation. So you put a small amount of air in the tires so they'll grab the road for traction, not pop the minute you hit anything like a pebble, and cushion you when you hit a bump. The fatter, less-filled tire has more contact with the ground and therefore loses more energy to friction, but it's powered by gas so that's acceptable.

The average road bike's purpose is EFFICIENT transportation, and it's powered by humans. They will want to go as far as possible with as little effort as possible, and will actively steer to avoid bumps and objects on the road so comfort is not as critical. So they pump the tires up very high to minimize the amount of contact between tire and ground and cut down on friction as much as possible so they don't have to work as hard to pedal it.