Why do we inflate bike tires?

Question

What is an explanation for the reasoning behind inflating bike tires?

Be specific and try to include scientific (at least pseudo-scientific) reasoning.

Answer 1

Air filled tires create a type of suspension.  Early bicycles with hard rubber tires were known as "bone shakers".   An air filled tire is more compliant and therefore offers better traction.  The more compliant tire also makes the bike faster because energy is used to propel the bike froward instead being lost to vibration.  An air filled tire also has more structural integrity than a hard rubber tire, it is less likely to slide off the rim or violently deform during high speed cornering ( at least in high pressure versions).  Many versions of "airless" tires have been introduced since the inception of pneumatic tires and have proven unreliable or hard on the rider.  Also, air pressure can be adjusted to suit riding conditions or rider and cargo weight.

Answer 2

A cushion of air is a softer ride than just a hard rubber tire.

also better handling

Answer 3

A: Air is light. Due to the fact that the tire is rotational mass, saving weight on the tire is very important.

2: Air can be "harder" than solid ribber. A track tubular pumped to 210 psi is WAY harder than solid rubber.

C: Air can be softer than solid rubber. Air is infinitely adjustable.

4: And finally, air filled tires can be easily and cheaply repaired.