A disc brake consists of a metal disc attached to the wheel hub that rotates with the wheel. Calipers are attached to the frame or fork along with pads that squeeze together on the disc. As the pads drag against the disc, the wheel - and thus the bicycle - is slowed as kinetic energy (motion) is transformed into thermal energy (heat). (In basic operation, disc brakes are identical to rim brakes.) A bicycle disc brake may be mechanically actuated, as with a Bowden cable, or hydraulically actuated, or a combination of the two.
The rider fits the bike properly, which will determine the efficiency for the rider. The bike should provide maximum comfort & stability for the rider, which will help transfer maximum power transfer for the rider. The design features also need to be kept in mind in order the rider gets maximum aerodynamics.
The right hand shift levers work the rear derailleur and the left hand shift levers work the front derailleur. The higher the gears the easier it is to pedal.
High gears are suitable when climbing up a hill whereas small gears help gather faster speed but take greater effort. So if you're riding along in gear number 3 for example and are coming to a stop sign, gradually switch to number 5 or 6 so it's easier to pedal when you start up again. Or if you're coming to an incline or a hill, do the same thing so you don't have to work as hard.
Manufacturers print a series of numbers on most bicycle tires. At a minimum you will see two numbers situated as follows: "700 X 23" or "26 X 1.75“.
The first number tells you the tire's diameter. The second number reveals tire width.
Another misconception is that an uncomfortable saddle should be replaced with a soft one. However, just as soft mattresses are not necessarily the most comfortable to sleep on, soft saddles are not necessarily the best to cycle on. Soft saddles don't provide much support for your body so you can quickly become tired and uncomfortable on longer rides.
A further misconception is that a wide seat is more comfortable than a narrow one. This really depends on the type of riding you'll be doing. Certainly, sleek racing saddles don’t look comfortable but wider seats create more friction and chafing when you're doing lots of pedalling (say on the road, or in a race). In general, the more you ride and pedal, the thinner and less obtrusive a saddle should be.