Ex. 16. Complete the table. Use the information from the text A

 

 

V. Oral Practice

Ex. 17. Speak on the topic “Gears” using the table of ex.14

Ex. 18. Prove that Gears play a very important role in mechanical engineering.

 

VI. Reading and comprehension

Ex.19. Read the text B without a dictionary for 10 minutes and explain what the fixed-gear bicycle is.

Fixed-gear bicycle

A fixed-gear bicycle An 18 tooth cog that attaches to the rear

hub of fixed-gear bike

 

A fixed-gear bicycle or fixed wheel bicycle, is a bicycle without the ability to coast. The sprocket is screwed directly on to the hub and there is no freewheel mechanism. A reverse-thread lockring is usually fitted to prevent the sprocket from unscrewing. Whenever the rear wheel is turning, the pedals turn in the same direction. By resisting the rotation of the pedals, a rider can slow the bike to a stop, without the aid of a brake. A fixed gear bicycle can even be ridden in reverse.

Most fixed gear bicycles only have one gear ratio. Some have a sprocket on each side of the rear hub, giving the choice of using one of two different gear ratios. Such a hub may have a fixed gear on each side (double-fixed) or a fixed gear on one side and a freewheel gear on the other (fixed-free). To change gear, it is necessary to remove, reverse and refit the rear wheel. Typically, the number of teeth on the sprockets will differ by one or two, for example 19 teeth on one side and 17 on the other, making the latter gear some 11 or 12% higher than the former (for the same chainring).

In the past Sturmey Archer made a fixed multi speed hub gear, the model ASC, allowing the rider to change gear while riding. Its successor company, SunRace Sturmey-Archer, plans to produce a modern equivalent, the S3X, in the near future.

Fixed gear bikes are alternatively known as fixie bikes, or simply fixies.

Uses

A fixed/freewheel rear hub A fixed- gear folding bike.

 

The track bicycle is a form of fixed-gear bicycle used for track cycling in a velodrome. But since a "fixed-gear bicycle" is just a bicycle without a freewheel, a fixed-gear bicycle can be any type of bicycle.

Traditionally, road racing and club cyclists would use a fixed wheel bicycle for training during the winter months, generally using a relatively low gear ratio, believed to help develop a good pedalling style. In the UK until the 1950s it was common for riders to use a fixed wheel for time trials. The fixed wheel was also commonly used, and continues to be used in the end of season hill climb races in the autumn. A typical clubmen's fixed wheel machine would have been a "road-path" or "road/track" cycle. In the era when most riders only had one cycle, the same bike when stripped down and fitted with racing wheels was used for road time trials and track racing, and when fitted with mudguards (fenders) and a bag it was used for club runs, touring and winter training. However by the 1960s multi-gear derailleurs had become the norm and riding fixed wheel on the road declined over the next few decades. Recent years have seen renewed interest and increased popularity of fixed wheel cycling in the UK.

In urban North America recently fixed gear bicycles have acheived tremendous popularity, with the rise of discernible regional aesthetic preferences for finish and design details of the bicycles. The rise in popularity of fixed-gear bicycles in the mid-2000s, complete with adaptations such as spoke cards, is attributed to bicycle messengers. Some messengers disparagingly refer to persons sporting these affectations as 'fakengers,' 'posengers' or 'hipsters'. Riders of fixed-gear bicycles are sometimes referred to as "Clan Members" in both a pejorative and affectionate sense.

Dedicated fixed-gear road bicycles are being produced in greater numbers by established bicycle manufacturers. They are generally low in price, and characterized by a more forgiving, slacker road geometry, as opposed to the steeper, more aggressive geometry of track bicycles. These too are made in increasing numbers at budget, or entry-level price and quality-points.

Fixed-gear bicycles are also used in cycle ball and artistic cycling.

A fixed-gear bicycle is particularly well suited for track stands, a manoeuver in which the bicycle can be held stationary, balanced upright with the rider's feet on the pedals.

A subset of fixed gear track bike riding is emerging from urban youth, often associated with hipsters, with roots in modern skateboarding and Freestyle BMX. Track bike tricks are largely unexplored and like the sport's precursors, have an overwhelming appreciation for style and originality. "Fixies" are also used for increased performance.

Notes:

To coast – пливти вздовж узбережжя

Hub – ступила колеса

Reverse – протилежність, зворотній хід

Trials – випробування

Pejorative-зневажливий

Affectionate - люблячий, ніжний

Ex.20. Agree or disagree with the following statements:

1. A fixed wheel bicycle is a bicycle without the ability to coast.

2. There are many freewheel mechanisms in the fixed-gear bicycle.

3. The rear wheel is turned, the pedals turn in the other direction.

4. Most fixed gear bicycles have only one gear ratio.

5. To change gear, it is necessary to remove, reverse and refit the rear wheel.

 

Ex. 21. Answer the following questions:

1. What is a track bicycle?

2. What would club cyclists use for training during the winter months?

3. Why have fixed gear bicycles recently achieved tremendous popularity in the North America?

4. What are the main characteristics of fixed gear bicycles?