Originally Posted by DanH
To be perfectly accurate, tread grooves and other molded patterns in the surface of a tire reduce paved surface traction. Maximum dry traction is found with a smooth tire, aka a slick....
Dan's quite right for friction in the rolling direction.
However, lateral friction on paved surfaces is HIGHER with tread grooves because they tend to dig in slightly. For nosewheel aircraft with the tread on the main tires, this promotes straightness down the runway, but for taildraggers, this increases, slightly, the tendency to depart from straightness in the direction of a ground loop.
I worked this out some decades earlier and ordered a pair of smooth tires for my Cessna 180. They proves so successful that I continued for well over 1,000 hours. I've landed with them on dry pavement, on wet pavement, on glare ice, on dirt, on grass and on gravel. And on a beach down in Baja. In every case they proved honest, reliable, and easier to control than treaded tires had been.
Smooth tires on pavement are a bit closer to what landing on grass is like, in terms of lateral control.
Tire wear was superb.
The tires were custom-ordered retreads from Wilkerson Tires in Crewe, VA. I discontinued doing this after they sent me two sets in a row with very poor sidewalls. Now the handling is back to normal (i.e., worse), and I've got to be a bit more careful.
I suspect that treaded nosewheel tires (that is, on the nosewheel rather than the mains) might tend to be a factor in nosewheel shimmy, but have nothing concrete to base that on.
On tailwheel airplanes, I do recommend that the tailwheel be treaded. Easier on the C-180, though than our RVs.
RV-3B, skinning the fuselage