Showing posts with label bikes. Show all posts
Tweet Share Share Share Share Share

January 04, 2020

1. Chain Drive


This is the drive system that an overwhelming majority of motorcycles implement. The sprocket connected to the gearbox output shaft is the driving sprocket and the one at the rear wheel is the driven sprocket, both are connected through a chain, which also comes in a variety of designs, but we’ll leave that discussion to some other day.
Now a chain drive system requires you to tighten it from time to time as the chain has a tendency to increase in length with time. There is an in-built provision in the swing-arm in motorcycles with chain drive systems to allow the rear wheel to move backwards by a limited extent. One has to check the motorcycle every 500-700 km for slack and adjust it if required. In addition, since chain drive systems are generally open to the elements and catch a lot of dust and grime, they have to be cleaned and lubricated every 500-700 km. This makes chain drive systems pretty service intensive and bothersome to an extent. Chain drive systems are also quite noisy, especially when the chain loosens. In addition to the regular maintenance they require, chain drive systems also need to be replaced every 15,000 to 25,000 km, depending on factors such as power output of the motorcycle, usage patterns and maintenance levels.

2. Belt Drive


A belt drive system isn’t as common as a chain drive system, though in terms of popularity, it stands at a distant second position. This setup comprises of a driving pulley towards the gearbox output shaft and a driven pulley at the wheel – the two pulleys are connected by a belt which has teeth, or grooves on the inner side, matching the grooves on the outer side of the pulleys.  The belt is made of a rubber-like, but mostly a very strong synthetic material which lasts a very long time. Modern drive belts are strengthened with steel wires inside and Kevlar coating outside – such belt systems can last really long. You can expect a well maintained belt drive on a motorcycle to last in excess of 100,000 km or even more. Unlike chain drive, which requires very frequent cleaning, tightening and maintenance, belt drives are relative maintenance free.
Seems too good to be true, doesn’t it? So if a belt drive system offers so many advantages, then why aren’t they used more commonly? Well, as the case with every good thing in the world, they have their own downsides too. Belt drive systems are essentially costlier to produce than a chain-sprocket system. Secondly, the power loss during the transmission, depending on how the system has been set-up, ranges anywhere from 9 to 15 percent, which is quite high compared to a chain drive system. Also, while a belt drive system does not require regular maintenance, if ever the belt or any other components of the system give way, they are much more expensive to replace than the chain and sprocket setup.
Belt drives are generally used in cruisers where they offer noise-free, smooth transmission for long distance riding. Since comfort and smoothness is more important here as compared to performance or fuel efficiency, the belt drive system lends itself well to the application.

3. Shaft Drive


shaft drive systems are the most expensive of the three systems we have here, and by some margin. They are, however, the sturdiest of the three, very smooth, and hardly ever need any maintenance. If designed and engineered well, drive shafts often last the life of a motorcycle without requiring any servicing or maintenance whatsoever. This system, as the name suggests, comprises of a shaft that’s connected to the gearbox output via a universal joint, which is essentially a coupling that facilitates transmission of rotary power at any selected angle. At the other end, the shaft is connected to the rear wheel hub via a spiral bevel gear. The bevel gear turns the direction of rotation of the shaft by 90 degrees to make the wheel turn. This entire drive system is bathed in oil for lubrication and sealed to protect it from any external elements, which makes it totally maintenance free.
Since shaft drive systems are heavy, expensive, and by themselves require more torque to work efficiently, they are not used on low-capacity or economy oriented motorcycles. They are used on large capacity (generally 600cc or above) motorcycles which produce good amounts of torque. Also, since shaft drive systems are very sturdy and reliable, they are often used in motorcycles built for the purpose of adventure, sports touring or adventure touring.These systems lose a lot of power during transmission. They are the most inefficient of the trio we have here and may bleed from 20 to 25% of the power by the time they transfer it to the rear wheel.


Read more »
Tweet Share Share Share Share Share

June 27, 2019
From cars and trucks to planes and trains, brakes work in a similar way on most different vehicles. There are even brakes in wind turbines! Here's a quick comparison of some common brake systems.
Bicycle
If you ride a bicycle, you know all about brakes. If you want to stop suddenly, you squeeze the brake levers on the handlebars. Thin metal cables running to the back and front wheels pull on small calipers, forcing thick rubber blocks to press against the wheels. As they do so, friction between the blocks and the metal wheel rims generates heat, reducing your kinetic energy, and bringing you safely to a stop.
Although most bicycles still use caliper brakes, some use disc or drum brakes instead (described below).
A closeup of bicycle brake blocks
Motorcycle
Motorcycles typically have disc brakes comprising a rotor and a brake pad. The rotor is a disc with holes (or slots) in it mounted on the side of the wheel. A brake pad, operated by a hydraulic cable, jams against the rotor to slow it down by friction. The holes in the rotor help to dissipate the heat generated.
Motorcycle brake rotor, brake block, and cable
Steam locomotive
The brakes on a steam locomotive work the same way as a car's and are even more obvious. You can see the brake just behind the wheel in this photo. It clamps against the locomotive's driving wheels to slow them down. Since there are no tires on the wheels, the friction that stops the train comes from the immense weight of the locomotive pressing the metal wheels down onto the track.
A closeup of a steam engine wheel with the brake shoe
Airplane
Airplanes have brakes inside their wheels to help bring them to a stop on the runway, but they can also use air brakes to increase drag (air resistance) and slow themselves down—a bit like parachutes. Jet fighters often have a speed brake, which is a large metal plate just behind the cockpit that can be hydraulically raised to increase drag and braking.
An F-15E Strike Eagle jet fighter airplane raises its aerodynamic speed brake to slow down as it comes into land.
Wind turbine
Wind turbines have brakes to stop their rotors (propellers) turning too quickly. The brake is mounted inside the nacelle (the square-shaped casing behind the propeller that contains the gearbox and generator). Most turbines have an anemometer on them to measure the wind-speed. If it rises above a safe level, the brakes come on automatically and bring the rotors to a standstill. It's a shame, because higher wind speeds mean more energy could be produced. But safety always comes first!
Wind turbine brake
A closer look at car brakes
Most cars have two or three different types of braking systems.
Disc brakes
Peer through the hubcap of a car's front wheels and you can usually see a shiny metal disc just inside. This is called a disc brake. When the driver steps on the brake pedal, a pad of hard-wearing material clamps onto the brake disc and rubs it to make it slow down—in a similar way to bicycle brakes.
A closeup of a Porsche sports car front wheel showing the brake disk behind
Drum brakes
Some cars have disc brakes on all four wheels, but many have drum brakes on the back wheels, which work in a slightly different way. Instead of the disc and brake block, they have shoes inside the hollow wheel hub that press outwards. As the shoes push into the wheel, friction slows you down.
Simple animation showing how drum brakes work.
Handbrake
A car's handbrake applies the two rear brakes (disc or drum) in a slower, less forceful way through a lever that's typically located between the front seats. When you pull on the brake, a system of levers tugs on a pair of sturdy cables that apply the brakes to the back wheels. The handbrake system is completely mechanical and, unlike the conventional pedal brakes, doesn't use hydraulic fluid. That means it can be used (with very great care!) as an emergency braking system if the normal brakes fail.

Read more »
Subscribe to: Posts (Atom)
Powered by Blogger.