page_title: Bicycle tire
section_title: Tread
hierarchical_section_title: Bicycle tire / Construction / Tread
caption_attribution_description: English: two mountain bike tires, same size (26, 2.1), but with different tread patterns,
context_page_description: A bicycle tire is a tire that fits on the wheel of a bicycle or similar vehicle. They may also be used on wheelchairs and handcycles, especially for racing. Bicycle tires provide an important source of suspension, generate the lateral forces necessary for balancing and turning, and generate the longitudinal forces necessary for propulsion and braking. Although the use of a pneumatic tire greatly reduces rolling resistance compared to the use of a rigid wheel or solid tire, the tires are still typically the second largest source, after air drag, of power consumption on a level road. The modern detachable pneumatic bicycle tire contributed to the popularity and eventual dominance of the safety bicycle.
  Bicycle tires are also used on unicycles, tricycles, quadracycles, tandem bicycles, bicycle trailers, and trailer bikes.
context_section_description: The tread is the part of the tire that contacts the ground to provide grip and protect the casing from ware.
  Compound
  The tread is made of natural and synthetic rubber that often includes fillers such as carbon black, which gives it its characteristic color, and silica. The type and amount of filler is selected based on characteristics such as wear, traction (wet and dry), rolling resistance, and cost. Oils and lubricants may be added as softeners. Sulphur and zinc oxide facilitate vulcanization. Some tires have a dual-compound tread that is tougher in the middle and grippier on the edges. Many modern tires are available with treads in a variety or combination of colors. Road racing tires with different tread compounds for the front and rear have been developed, thereby attempting to provide more traction in front and less rolling resistance in the rear.
  Pattern
  Treads fall somewhere along the spectrum from smooth or slick to knobby. Smooth treads are intended for on-road use, where a tread pattern offers little to no improvement in traction. However, many otherwise slick tires have a light tread pattern, due to the common belief that a slick tire will be slippery in wet conditions. Knobby treads are intended for off-road use, where the tread texture can help improve traction on soft surfaces. Many treads are omnidirectional—the tire can be installed in either orientation—but some are unidirectional and designed to be oriented in a specific direction. Some tires, especially for mountain bikes, have a tread which is intended either for the front wheel or the rear wheel. A special tread pattern, with small dimples, has been developed to reduce air drag.
  Profile
  The profile of the tread is usually circular, matching the shape of the casing inside it and allowing the tire to roll to the side as the bicycle leans for turning or balancing. More-squared profiles are sometimes used on mountain bike tires and novelty tires designed to look like automotive racing slicks, as on wheelie bikes.
caption: Different treads on knobby mountain bike tires
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