Why a Smooth Tread on Road Tires?

The oval shape of a bicycle road tire contact patch permits effective water evacuation to help keep the tire from hydroplaning.

The footprint of a 23mm tire (approx. 7 sq. cm) is so small that the bike would need to be traveling at about 120MPH in order to hydroplane.

Nevertheless, some road tire models are designed with specific tread structures – primarily for cosmetics or to comfort the consumer. Sometimes tread features can help provide a harder rubber compound a better mechanical link with the road surface, for better grip.