Bicycle tire (info Zobe)

 
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.[1] The modern detachable pneumatic bicycle tire contributed to the popularity and eventual dominance of the safety bicycle.[2]

History New Mail Ladies Safety bicycle

, circa 1891, with solid rubber tires A tubed, clincher tire showing the inner tube protruding between the tire and the rim Tubular tire rolled from rim to show glue between them Clincher cross section schematic with 1: rim, 2: rim strip, 3: rim braking surface, 4: bead core, 5: inner tube, 6: casing, 7: tread The first bicycle "tires" were iron bands on the wooden wheels of velocipedes.[3] These were followed by solid rubber tires on penny-farthings.[4] The first patent for "rubberized wheels" was granted to Clément Ader in 1868.[5] In an attempt to soften the ride, rubber tires with a hollow core were also tried.[6] The first practical pneumatic tire was made by John Boyd Dunlop in 1887 for his son's bicycle, in an effort to prevent the headaches his son had while riding on rough roads. (Dunlop's patent was later declared invalid because of prior art by fellow Scot Robert William Thomson.) Dunlop is credited with "realizing rubber could withstand the wear and tear of being a tire while retaining its resilience".[7] This led to the founding of Dunlop Pneumatic Tyre Co. Ltd in 1889. By 1890, it began adding a tough canvas layer to the rubber to reduce punctures. Racers quickly adopted the pneumatic tire for the increase in speed it enabled. Finally, the detachable tire was introduced in 1891 by Édouard Michelin. It was held on the rim with clamps, instead of glue, and could be removed to replace or patch the separate inner tube.

 Attaching to the rim Three main techniques for attaching a bicycle tire to a rim have been developed: clincher, wired and tubular.[8] Clinchers originally did not have wire in the beads and the shape of the bead interlocked with a flange on the rim, relying on air pressure to hold the tire bead in place. However, this type of tire is no longer in general use and the term clincher has transferred to the modern wired-on tire. For the remainder of this article, the modern use of the word clincher will be assumed. In an attempt to provide the best attributes of both wired and tubular methods, tubular clinchers have also been offered.[9] Clincher Most bicycle tires are clincher for use with "clincher" rims. These tires have a steel wire or Kevlar fiber bead that interlocks with flanges in the rim. A separate airtight inner tube enclosed by the rim supports the tire carcass and maintains the bead lock. An advantage of this system is that the inner tube can be easily accessed in the case of a leak to be patched or replaced. The ISO 5775-2 standard defines designations for bicycle rims. It distinguishes between Straight-side (SS) rims Crochet-type (C) rims Hooked-bead (HB) rims Traditional wired-on rims were straight-sided. Various "hook" (also called "crochet") designs re-emerged in the 1970s to hold the bead of the tire in place,[10] resulting in the modern clincher design.

          This allows higher (80–150 psi or 6–10 bar) air pressures than older wired-on tires. In these designs, it is the interlocking of the bead with the rim, not the tight fit or resistance to stretching of the bead, that keeps the tire on the rim and contains the air pressure.[12] Some clincher tires can be used without tubes in a system which is referred to as tubeless. Typical tubeless tires have airtight sidewalls and beads which are designed to maximize the seal against the rim. Tubular or sew-up Main article: Tubular tyre Some tires are torus-shaped and attached to tubular rims with adhesive. The rim provides a shallow circular outer cross-section in which the tire lies instead of flanges on which tire beads seat. Providing suspension Adequate stiffness is necessary to support the rider, while softness is desirable for cushioning. Most bicycle tires are pneumatic—the stiffness is provided by pressurized air. Airless tires use some kind of elastomer instead. Pneumatic tires A bicycle inner tube with valve stem In a pneumatic tire, pressurized air is held inside either with a separate, relatively impermeable inner tube, or by the tire and rim, in a tubeless system. Pneumatic tires are superior in providing effective cushioning while keeping rolling resistance very low. Tubed A tubed tire has a separate inner tube, made of butyl rubber or latex, that provides a relatively airtight barrier inside the tire.[13] A vast majority of the tire systems in use are clinchers, due to the relative simplicity of repairs and wide availability of replacement inner tubes.

                Most of bicycle inner tubes are torus-shaped balloons while some are not. For example, inner tubes in bicycles of the Moscow bike-sharing service are simply rubber tubes long enough to be coiled and inserted into a tire.[14] Tubeless Main article: Tubeless tire Tubeless tires are primarily used on mountain bikes due to their ability to use low air pressure for better traction without getting pinch flats.[15] Tubeless tires work similarly to clinchers in that the bead of the tire is specifically designed to interlock into a corresponding tubeless rim, but without an inner tube. Air is inflated directly into the tire, and once "locked" into the rim, the system is airtight. Liquid sealants are often injected into tubeless tires to improve sealing and to stop leaks caused by punctures. An advantage is that pinch flats are less common in a tubeless setup because they require a hole through the tire carcass, not just the inner tube. A disadvantage is that air can escape if the bead lock is compromised from too much lateral force on the tire or deformation of the rim/tire due to hard impact with an object. Tubeless tires require tubeless-compatible rims, which do not allow air to escape where the spokes connect and have a different shape groove for the tire bead to seat. Road tubeless In 2006, Shimano and Hutchinson introduced a tubeless system for road bicycles.[16] Tubeless tires have not yet gained popular acceptance in road racing due to lack of sponsorship, the tradition of using tubular tires and the fact that, even without the inner tube, the combined weight of tubeless rims and tires is more than top-of-the-line tubular tire wheelsets.[17] Road tubeless is gaining popularity among riders for whom the benefits are worth the costs.

                Road tubeless tires tend to be a much tighter fit than traditional clincher tires, which makes mounting and removing the tire more difficult. Airless tires Mobike airless tire Airless were used before pneumatic tires were developed, appearing on velocipedes by 1869.[19][20] They continue to be developed in an effort to solve the problem of losing air pressure, either from a puncture or from permeability. Modern examples of airless tires for bicycles include BriTek's Energy Return Wheel,[21] an airless bicycle tire from Bridgestone,[22] the tire pictured to the right on a Mobike, and solid tires discussed below. Although modern airless tires are better than early ones, most give a rough ride and may damage the wheel or bicycle.[23] Solid The most common form of airless tire is simply the solid tire. Besides solid rubber, solid tires made of polyurethane[24][25][26][27][28] or microcellular foam[29] are also offered for 100% flat prevention. Much of the desirable suspension quality of the pneumatic tire is lost, however, and ride quality suffers.[30] Many bicycle-sharing systems use these tires to reduce maintenance, and examples of solid tires include those available from Greentyre,[31] Puncture Proof Tyres Ltd,[32] KIK-Reifen,[33] Tannus,[31] Hutchinson,[34] and Specialized.[35] Construction