Road bicycles like the ones used in the Tour de France use pressures in the 120-140 psi range, but cars generally float around the 32 psi area.
Probably less these days as it’s shown lower pressures and larger tires can improve performance.
Yes fuel economy. Energy expended per distance traveled or power needed to maintain a given speed. Just the fuel in this case is burned by your own body.
At world class levels, a few watts here and there will make a big difference by the end of a race.
Source?
All the studies I’ve read (and my experience) show that narrower tires and higher pressures improve economy. Less traction and less ride comfort are the tradeoffs, respectively.
GCN has a number of videos on this subject: https://youtu.be/jTZfrBVr5pQ?si=M5v6KP5ZZ9ZU5MXz
https://youtu.be/AK5KLvrzrb4?si=aMcYxYnWi9poZ8SA
And here is some technical data from SRAM: https://www.sram.com/globalassets/publicsites/cms-campaign-pages-not-story-pages/zipp/totalsystemeffeciency/pdf-downloads/tse-explained2.pdf
Basically new data includes vibration losses which get larger as pressure increases. There’s a sweet spot to balance between rolling resistance (which decreases with pressure) and vibration (which increases with pressure). So when you mention ride comfort as a trade off, it actually has a much larger effect than you might imagine.
