transmission
torque is the torsion force of a point, sometimes called "moment".torque defines the force multiplied by the distance perpendicular to the pivot of the force.
Torque = force x distance Perp.to pivot
For example: A foot-pound torque is the torsional force required to support a pound of weight on a weightless horizontal rod one foot from the pivot.you use a torque wrench to tighten the nut to the specified torque, you can directly measure the torque.here, a torsional force is applied to the nut until the rotational resistance of the nut is equal to the required torque.
work is the transfer of energy.is equal to the applied force multiplied by the distance traveled in the direction of the force.
work = force x travel distance
Work + Time = Power
power is the rate at which work is done and the amount of work completed per unit time.is the work done divided by the time taken.For example, if a heavy object is firmly fixed to the floor and you try to lift it, you are applying force. However, the heavy object cannot move, so no work is done on the heavy object.Although your arm exerts strength, no energy is transferred to weight.If you lift a pound-heavy object by one foot, then by definition, a foot-pound job has been completed.if you take a minute to do this, then you will generate energy at a rate of one foot pound per minute.
one horsepower is 33,000 foot pounds per minute.In order to find the horsepower of the engine, measure the torque produced by the engine and calculate the horsepower.this is done using a dynamometer, which is essentially a brake with a measuring device-so the term brake horsepower (bhp) is often used.generates a torque curve by plotting the torque measured with respect to the engine speed.torque in feet and pounds:
torque x RPM 5252 = horsepower
how does this apply to motorcycles?
For riders, torque is the most important factor.bike will accelerate at a speed that matches its torque curve (ignoring rolling/air resistance).torque peak is the point where the bicycle has the maximum acceleration, and either side of the peak is smaller.For a given rear wheel torque, the acceleration of the bicycle is the same regardless of the engine speed.horsepower increases as the engine speed increases until after the torque peak, and only reaches the peak when the reduced torque compensates for the increased speed.(Look at the equation.) The acceleration at the torque peak is greater than the acceleration at the power peak.then why do we talk so much about horsepower?consider a large waterwheel.Although it is obvious that the torque generated by the waterwheel is very large,its rotation speed is very slow, its power (ability to do work over time) is very low.Therefore, waterwheels are usually not very powerful.powerful engine with a large amount of horsepower is an engine that produces high torque at high speeds.
In theory, it is better to produce torque at high speeds than at low speeds, because you can use gear transmissions at high speeds.powerful engine is useful because it can slow down-you don't want the rear wheel speed of the bike to reach 8000 rpm anyway!deceleration will reduce the speed of the rear wheels, and the torque will increase accordingly.In addition to friction loss, this will not affect the power of the engine.By the way, the chain transmission efficiency of proper lubrication is 98.5%, which is obviously better than gear transmission.for road racing, this theory is very consistent with reality, but for off-road racing, the above is not the only consideration.(still awake?!...)
But what does this mean for the transmission...
your bicycle's stock transmission may be determined by choosing a compromise ratio, which is based on the ratio that is most effective for the test rider under "average" conditions.Once the bicycle is out of average conditions due to engine adjustments, terrain, track design or rider style, the backup transmission may no longer be the best solution-different settings may allow you to bypass the track faster.
when the driving force is completely balanced by air and rolling resistance, the maximum speed will appear.The acceleration has dropped to zero.
setting the transmission of any vehicle is a trade-off between acceleration and maximum speed.
using a larger countershaft (gearbox) sprocket or a smaller rear sprocket can accelerate the bicycle to produce a higher top speed and less acceleration.
use a smaller countershaft (gearbox) sprocket or a larger rear sprocket to reduce the bicycle's gear so that it achieves greater acceleration at lower top speeds.
ratio chart shows the transmission ratio of different tooth numbers on the gearbox and rear sprocket.is the number of revolutions of the gearbox sprocket required to make the rear wheel rotate one full turn.These figures are calculated by dividing the number of teeth on the rear sprocket by the number of teeth on the gearbox sprocket.
It can be clearly seen from the table that replacing a tooth on the gearbox sprocket has a significantly greater effect on the gear transmission than replacing a tooth on the rear sprocket.Therefore, in order to make a slight change to the gear, it is necessary to change the size of the rear sprocket by one tooth, because replacing the gear box sprocket will cause a greater difference in the gear.
