Sunday, June 26, 2011

bike tyre

Parts of a Tyre

  • Clincher Tyres

    Conventional tyres used on 99% of all bicycles are "clincher" type, also known as "wire-on." They consist of an outer tyre (the "casing") with a U-shaped cross section, and a separate inner tube. The edges of the tyre hook over the edges of the rim, and air pressure holds everything in place.
    Many people suppose that tyres are made out of rubber, because that's what is visible. This is a major oversimplification--rubber is the least important of the three components that make up a tyre:

    • Bead

      The "bead" is the edge of the tyre. On most tyres, the beads consist of hoops of strong steel wire. The beads hold the tyre onto the rim, and are, in a sense, the "backbones" of a tyre. While most beads are steel, some tyres use Kevlar ® cord instead.
    • Fabric

      Cloth fabric is woven between the two beads to form the body or "carcass" of the tyre. This is the heart of the tyre, the part that determines its shape. The vast majority of tyres use nylon cord, though some use other polyamides. Up until the 1960s, cotton/canvas was commonly used. It was not as strong, and was prone to rot. Cotton and silk are still used for some tubulars.
      The fabric threads don't interweave with crossing threads as with normal cloth, but are arranged in layers or "plies" of parallel threads. Each layer runs perpendicular to the next layer(s).
      Some tyres use thick thread, some use thin thread for the fabric. With thin thread, there are more threads per inch ("TPI") and this number is often considered an important indication of tyre performance.
      The higher the TPI number, the thinner and more flexible the tyre fabric is. Thin-wall (high TPI) tyres tend to be lighter and have lower rolling resistance, but they're more easily damaged by road hazards.
      Bicycle tyres have the threads of the fabric running diagonally, ("bias") from bead to bead. Modern car tyres have the main threads running straight over from one bead to the other, known as "radial" construction. Radial tyres will also have a "belt" of plies running all the way around the circumference of the tyre, crossing the radial plies.
      Radial tyres have been tried for bicycles, but they tend to be too floppy from side to side. This floppiness feels quite unpleasant in actual riding --much like the feel of a grossly under-inflated tyre.
      Some bicycle tyres also have a Kevlar ® belt running under the tread area, in addition to the normal bias plies. This is intended as a puncture preventive.
    • Rubber

      Once the fabric has been woven between the beads, and the tyre has its basic shape, it is coated with rubber. The rubber is mainly there to protect the fabric from damage, and has no structural importance.
      The rubber that comes into contact with the ground is called the "tread." This area usually has thicker rubber than the "sidewalls" of the tyre, mainly for wear resistance. Most tyres have some sort of 3-dimensional pattern moulded into the tread, which may or may not enhance traction.
      Manufacturers mix different additives with the rubber to achieve desired traction/wear characteristics. Generally, a softer formulation will give better traction, but at the expense of more rapid wear. Rubber is normally a sort of tan colour, but most tyres are black. This is the result of adding carbon black to the mix. Carbon black considerably improves the durability and traction of the rubber in the tread area.
      Some manufacturers substitute a silicon compound for the carbon black. These tyres usually have a grey tread. Whether silicon or carbon black provides better traction is subject to dispute. Grey-tread tyres are preferred for indoor use (for example, on wheelchairs), because they do not leave black marks on floors.
      "Dual compound" tyres feature a centre strip of fairly hard rubber for improved wear, with a softer, grippier formulation toward the sides of the tread. The intent is to provide better cornering traction without compromising the life span of the tread.
      Many bicycle tyres are "gumwalls" or "skinwalls." Gumwall tyres have tan sidewalls, with no carbon black. This may make the sidewalls slightly more flexible, reducing rolling resistance. It is not clear to what extent this makes a difference.
      Skinwalls have either no rubber on the sidewalls, or a very thin layer. This, too is an attempt to make the sidewall more flexible and reduce rolling resistance.
    • Tubular Tyres

      Tubular tyres, also known as "sew-ups" or "sprints" differ from clinchers in that they don't have beads. Instead, the two edges of the tyre are sewn together around the inner tube. Tubulars are used on special rims, and are held on to the rims by glue. Tubulars used to be fairly common on high-performance bicycles, but these days they are an endangered species.
      Tubular Pros: Tubular Cons:
      • Tubulars are a bit lighter than comparable clinchers, due to the absence of the beads. The development of Kevlar® beads has considerably reduced this advantage.
      • Tubular rims are lighter than clincher rims, since they don't need the flanges that hold the beads of a tyre in place.
      • Tubulars are less prone to pinch flats than clinchers, since the rims don't present the sharp edges of the clincher flanges.
      • Many riders believe that tubulars provide a more comfortable ride and better traction than clinchers.
      • If you get a flat on a tubular, you can install a spare tubular faster than you can change an inner tube in a clincher.
      • Tubulars are considerably more expensive than clinchers of comparable performance.
      • Tubulars are very much harder to repair once punctured. Most people just throw them away.
      • You need to carry a complete spare tubular in case you get a flat. This negates the weight advantage over clinchers, unless you have a team car following you with spare wheels.
      • Improperly glued tubulars can roll off the rim. This almost always causes a serious crash.If you replace a tubular on the road, you cannot corner safely at high speeds until you go home and re-glue the tyre. For safe high-speed cornering, the glue needs to dry for at least several hours.
      • Tubulars have higher rolling resistance than the best clinchers.
      • Tubulars are rarely as true and round as clinchers.

    • Inner Tubes

      An inner tube is basically a doughnut-shaped balloon, with a valve for inflation. The only requirement for an inner tube is that it not leak. Being of rubber, it has no rigid structure. If an inner tube is inflated outside of a tyre, it will expand to 2 or 3 times its nominal size, if it doesn't explode first. Without being surrounded by a tyre, an inner tube can't withstand any significant air pressure

      Valve Types:
      Schrader Presta Woods
      Schrader valve Presta valve Woods/Dunlop valve

      Butyl vs Latex

      Before World War II, tyres and tubes were made from natural latex rubber, harvested from tropical trees. When the supply of natural latex was insecure during the war, a substitute, "butyl" was invented. Butyl turned out to be a very successful substitute, better, in fact, than latex for this application. All modern tyres and most inner tubes use butyl rubber.
      Some riders prefer latex inner tubes, because they can be a bit lighter than butyl ones. Some riders believe that latex tubes have less rolling resistance than butyl.
      Latex tubes are commonly a bit more porous than butyl ones, and need to have their pressure topped off more often.
    Spoke Divider

    How a Tyre Supports its Load

    It is commonly thought that the air pressure in a tyre supports the rim. If you think about it, this can not be true because the air pressure against the rim is equal, top and bottom. How, then, does a tyre support its load?
    First of all, the role of air pressure in the tyre is to hold the fabric under tension -- in all abut one place, the contact patch with the road surface.
    At the contact patch, the tread of the tyre is flattened against the road. Air pressure can only push directly outward, and so here, it pushes directly downward. The downward force of the air must equal the weight load, and so the area of the contact patch equals the weight load, divided by the air pressure. For example, if the air pressure is 50 PSI, the contact patch will be two square inches.
    The threads of the tyre fabric can only transmit loads lengthwise and in tension. They bulge out to the sides. How then, is the load transfered from the contact patch to the rim?
    The load is first transferred from the contact patch to the tyre sidewalls by the shallower angle and lower tension of the threads either side of the contact patch -- they are pulling downward less and outward more. The load is similarly transferred from the sidewalls to the rim by the shallower angle and lower tension of the threads of the fabric where they meet the rim. As the threads pull downward less, they also pull outward more, but the outward forces at the two sides are equal and opposite, and cancel out.
    These effects together produce the bulge seen at the bottom of a tyre under load. Because the contact patch is flat aganst the road, the curvature of the sidewalls is increased -- the tyre becomes effectively thinner, not counting the inactive width of the contact patch.
    Wth a bias-ply tyre, the load is carried lengthwise in both directions along the tyre by the diagonal threads, so the bulge is longer and less deep than on a radial-ply tyre. In the early days of radial-ply car tyres, people often thought they were underinflated, because the bulge at the bottom was more pronounced.
    A tyre, then, supports its load by reduction of downward pull, very much the same way that spoking of the wheel supports its load. The tension-spoked wheel and the pneumatic tyre are two examples of what are called preoaded tensile structures, brilliant, counterintuitive designs working together remarkably to support as much as 100 times their own weight.
    Bias plies also help to transmit lateral and torque loads, by triangulating the connection between the contact patch and the rim -- much like the way the spokes of a semi-tangent spoked wheel transmit lateral and torque loads. With tubulars, the diagonal plies also work like a Chinese finger puzzle: the air pressure makes the tyre fatter, and so makes it shorter and helps hold it to the rim.
    If you would like to get into mathematical details, there is an excellent technical description in an old Britannica encyclopedia article online.

Wednesday, June 22, 2011

bikes in nepal


SUZUKI


Suzuki-BKING
Suzuki B-King


Model : GSX1300BK
Engine: 1,340cc, 4-stroke, 4-cylinder, DOHC, 16-valve, liquid-cooled
Starter: Electric
Transmission: 6-speed
Front suspension: Inverted telescopic, 43mm titanium nitride inner tube, fully adjustable rebound/compression/preload progressive linkage, fully adjustable
Rear suspension: Rebound/compression/preload
Front brakes: Disc brake, twin
Rear brakes: Disc brake
suzuki-GSR600
Suzuki GSR-600


Engine: Four stroke, liquid-cooled, DOHC
Bore: 67mm x 42.5mm
Compression ratio: 12.5 : 1
Lubrication: Wet sump
Ignition: Electronic ignition (Transistorised)
Fuel system: Fuel injection
Starter: Electric
Transmission: 6-speed constant mesh
Suzuki-Hayabusa
Suzuki Hayabusa


Engine capacity: 1340cc
Engine: 4-stroke, 4-cylinder, liquid-cooled, DOHC
Bore: 81mm x 65mm
Compression ratio: 12.5 : 1
Lubrication: Wet Sump
Ignition: Electronic ignition
Fuel system: Fuel Injection
Transmission: 6-speed constant mesh
Suzuki-GS150R
Suzuki-GS150R


Engine Type : 4-stroke, Air-cooled, SOHC
Bore x Stroke (mm) : 57.0 x 58.6
Displacementn (cm3) : 149.5
Max Power : 13.8bhp@8,500rpm
Max Torque : 13.4Nm@6,000rpm
Compression Ratio : 9.35:1
Carburetor : BS26 with TPS
Ignition: CDI
Transmission : 6-speed (1-down, 5-up)
Starting : Electric & kick
Suzuki-DR200SE
Suzuki-DR200SE


Engine 4-stroke, air-cooled, OHC
Bore & Stroke 66.0 mm (2.60 in) x 58.2 mm (2.29 in)
Compression Ratio 9.4 : 1
Fuel System MIKUNI BST31SS, single
Lubrication Wet sump
Ignition Electronic ignition (Transistorized)
Starter Electric
Transmission 5-speed constant mesh
honda-unicorn
Honda Unicorn


Engine: 4 Stroke, Air Cooled OHC, Single Cylinder,150cc

Gears: 5 Speed

Top Speed: 101kph

Cooling Type: Air Cooling
TVS

tvs_rtr-160
TVS Apache RTR-160


Engine : 160 cc



Mileage : 45 km
rtr180
TVS Apache RTR-180


Engine : 180 cc



Digital Speedometer,Rear Disc Brake, Aerodynamically designed Air Scoops
HartFord VR

Hartford-VR-150H
Hartford VR 150H


Engine : 4 stroke, Air cooled 150 cc

Mileage : 37 km

Brake Type : Front+ Rear Disc
Hartford-VR-200H
Hartford VR 200H


Engine : 4 stroke, Oil + Air cooled 200 cc
Mileage : 30 km
Brake Type : Front+ Rear Disc
    

Saturday, June 18, 2011

scooter

A scooter is a motorcycle with step-through frame and a platform for the operator's feet. Elements of scooter design have been present in some of the earliest motorcycles, and motorcycles identifiable as scooters have been made from 1914 or earlier. Scooter development continued in Europe and the United States between the World Wars.
The global popularity of scooters dates from the post-World War II introductions of the Vespa and the Lambretta. These post-war scooters were intended to provide low-power personal transportation (engines from 50 to 250 cc). The original layout is still widely used in this application. Maxi-scooters, with engines from 250 to 800 cc have been developed for Western markets.
Scooters are popular for personal transport, partly based on their low cost of purchase and operation and on benefits that include convenience in parking and storage. Licensing requirements for scooters are easier and less expensive than those for cars in most parts of the world, and insurance is generally cheaper.


A motor scooter is a motorcycle similar to a kick scooter with a seat. a floorboard, and small or low wheels. The United States Department of Transportation defines a scooter as a motorcycle that has a platform for the operator's feet or has integrated footrests, and has a step-through architecture.
The classic scooter design features a step-through frame and a flat floorboard for the rider's feet. This design is possible because most scooter engines and drive systems are attached to the rear axle or under the seat. Unlike a conventional motorcycle, in which the engine is mounted on the frame, most modern scooters allow the engine to swing with the rear wheel. Most vintage scooters and some newer retro models have axle-mounted engines with a manual transmission and the gear shift and clutch controls built into the left handlebar. Most newer scooters use a continuously variable transmission (CVT).
Scooters usually feature bodywork, including a front leg shield and body that conceals all or most of the mechanicals. There is often some integral storage space, either under the seat, built into the front leg shield, or both. Most scooters have small engines, 50 cc to 400 cc with a single cylinder, although maxi-scooters might have twin cylinder 400 to 800 cc engines.[citation needed]
Traditionally, scooter wheels are made of pressed steel, bolt on easily, and are often interchangeable between front and rear. Some scooters carry a spare wheel. Many recent scooters use conventional front forks with the front axle fastened at both ends, while some have twin shock rear swingarms

Scooter-like traits began to develop in motorcycle designs around the 1900s. In 1894, Hildebrand & Wolfmüller produced the first motorcycle that was available for purchase. Their motorcycle had a step-through frame, with its fuel tank mounted on the down tube, its parallel two-cylinder engine mounted low on the frame, and its cylinders mounted in line with the frame. It was water-cooled and had a radiator built into the top of the rear fender. It became the first mass-produced and publicly-sold powered two-wheel vehicle, and among the first powered mainly by its engine rather than foot pedals. Maximum speed was 40 km/h (25 mph). The rear wheel was driven directly by rods from the pistons in a manner similar to the drive wheels of steam locomotives. Only a few hundred such bikes were built, and the high price and technical difficulties made the venture a financial failure for both Wolfmüller and his financial backer, Hildebrand.
In France, the Auto-Fauteuil was introduced in 1902. This was basically a step-through motorcycle with an armchair instead of a traditional saddle. Production continued until 1922