Why has someone not designed a landing wheel with a fin or fins on it so that the air will start the wheels turning before the wheels touch the ground? Wouldn't that preserve the tires longer from wear? Or would it make the control of the aircraft more dangerous in some circumstances, such as rain or snow, to have the wheels already turning when landing? If so, perhaps the fins could be manually or computer controlled for various weather conditions.
This has been researched over the years, but it seems that the solutions did not find wide application. The oldest I could find is from 1941 (see page 112 in the September 1941 issue of Popular Science), and there have been several attempts to implement a spin-up turbine. See “Wheels with wings” on NewScientist Blogs or “Spin Wheels Before Landing”, a discussion thread on Eng-Tips forums, for more. The biggest problem seems to be the inertia of the spinning wheel because it makes the aircraft react in funny ways if the pilot wants to correct his approach.
The rough field package on the Cessna Citation 500 uses this technique (for the nose wheel only) to protect the fuselage from debris which could be kicked up by the wheel spinup.