- Speed selector
- Phillips screwdriver
history of bicycles.The history of the bicycle is quite interesting.The first of these, which appeared in the late 19th century, more like a scooter and had a very low rate.There were options for bikes with stepping arrangements, where they had to travel standing.At the beginning of the 20th century, there was actually a boom velosipedostroeniya.That's when the bicycle is widespread.At that time, the bikes were a huge front wheels, to which were attached directly to the pedal, and accordingly a very high planting.The real revolution was the use of bicycle chain thrust when the force transmitted to the rear wheel by means of sprockets and chains.But I had not yet thought about analog automotive transmissions.
Gear change on the bike.Thus an analogue speed steel bike.The device is in the form of elementary, but behind it there is an interesting engineering fiction.The fact that the higher the rate of rotation cyclist
For one turn the pedals can get a few revolutions of the drive wheel.This is the basic principle of velocity.On the pedal set is sufficiently large sprocket and the rear wheel is small.How many times the circumference of the sprocket to sprocket wheel is less on the pedals, so much speed rear wheel will make for one pedal revolution.By means of simple mathematical calculations can be determined that if the radii are Stars as 1/2 1/3 1/4, the number of revolutions, i.e. the gear ratio is 4.9, 16, respectively.Thus the gear ratio increases exponentially.How to switch on a bicycle speed in order to obtain the most effective flow of their own efforts?Do not forget that with the increase of the transmission number is increasing not only the greatest possible speed, but reduces the time effort.Therefore we can not all the time to ride at top speed.During the launch and acceleration is the best option - to switch to high speed, and to achieve a high rate of drive are gradually switched to maximum speed.
during launch and acceleration is the best option - to switch to high speed, and to achieve a high rate of drive are gradually switched to maximum speed.If you have to go up the hill, then the best option would be to switch the speed to the minimum in order to obtain the greatest moment of force on the wheel.When driving downhill is quite possible to start with maximum speed immediately.Technically, speed changers, usually come in two types: a bicycle bell and a motorcycle switch.For the first type it requires less effort, but it quickly goes down.The second is more practical.On bikes equipped with locks have special rates in the form of screws, regulate the tension wire ropes, the switching speed.For most long operation switches is from time to time to tighten them.