BICYCLE TYRE

A bicycle tyre gets quite hot during its inflation. The work of inflating the tyre explains in part why the temperature increases, but careful calculations (e.g. see pp. 86 and 89) show that additional factors are responsible for the rise in temperature. 

We look on p. 86 at the effect of performing work while inflating a bicycle tyre, and the way work impinges on the internal energy of the gas. 

Why is it such hard work pumping up a bicycle tyre ... 

Why, when letting down a bicycle tyre, is the expelled air so cold ... 

We see how the spontaneous movement of gas always occurs from high pressure to low pressure, and also explains why a balloon will deflate or pop on its own, but work is needed to blow up the balloon or inflate a bicycle tyre (i.e. inflating a tyre is not spontaneous). 

Safety uses are very wide and many new examples appear regularly. For instance, American Tire has patents and patents pending relating to the production of urethane flat free tyres, including bicycle tyres that are also available in a fluorescent yellow that can be seen at night by headlights from a distance of about 200 feet. 

Recent developments by DuPont in high performance car tyres have shown that inclusion of para-aramid as Kevlar EE, which is a pre-dispersed form of Kevlar pulp, in the rubber sidewall apex increases stiffness and improves cornering efficiency. The apex is part of the located radially outward of the tyre s bead (see Fig. 11.1 (a) and (b)). The EE stands for Engineered Elastomer and DuPont has introduced Kevlar EE into beltings, seals and gaskets, and bicycle tyres to improve resistance to abrasion, tear and puncture, modulus, and cut and chip resistance. ... 

When a solvent-based system is applied to a porous or permeable substrate, the solvent may pass out of the bond throngh the adherends. When the adherends are relatively impermeable, a common practice is to coat both mating surfaces and allow them to become snbstantially dry before bringing them into contact while the adhesive stUl retains some degree of Tack. This technique is familiar to many through its application to the repair of punctures in bicycle tyres or the lamination of decorative ( melamine ) laminates to various substrates. 

China clay is a widely used white filler in the rubber industry. Depending on particle size, it can be used as a semi-reinforcing filler (hard clay) or a non-reinforcing filler (soft clay) in such applications as chemical liners, bicycle tyres, conveyor belts, shoe soles, gaskets and flooring. Its use in plastics is much more limited. In thermoplastics it is used for speciality antiblocking, in thermosets it is used in urea-, phenol- and melamine formaldehyde, in unsaturated polyesters, and in epoxy resins. 

Next the air is forced into a small space, or compressed. That makes it hot (just like air gets hot when you pump it into a bicycle tyre). It is then cooled down again. 

In 1898 the first rubber factory based on the natural product, Suomen Gummitehdas Oy (later Oy Nokia Ab rubber factory), was set up to produce galoshes, i.e. overshoes. The firm specialized in rubber footwear and flourished. In 1926 it began to manufacture tyres for bicycles, and in 1934 tyres for cars. Two years later it introduced its own innovation, winter tyres for cars. The growth of the rubber industry was outstanding. In 1913, it employed over 90 employees and in 1938 as many as 2,570, or 82 per cent of the total workforce of the main chemical industry and 42 per cent of its output, as shown in table 1. Before the Winter War of 1939-40, rubber manufacturing was one of the three biggest chemistry-related branches of Finnish industry. ... 

Reinvented by John Boyd Dunlop Pneumatic tyres for bicycles... 

Butyl rubber is used as material for bicycle res due to its low permeability for air. If a tyre contains 2400 cm (STP) of air at a pressure of 2 bar bow long will it take before the tyre is completely flat. Assume that the the driving force remains constant. The thickness ofthe tyre is 1 mm, the surface area 2400 on, andtheairpermeabilityisO.9... 

The random kinetic energy of particles in matter can be increased in a number of ways. For example, solar energy from the Sun being absorbed by sea water, striking a piece of metal with a hammer many times, compressing the air in a tyre pump for a bicycle or simply using a flame. 

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