A bicycle frame is the main component of the bike, where the wheels and other components are installed. Modern and most common frame design for upright bikes is based on safety bikes, and consists of two triangles: the main triangle and the rear triangle in pairs. This is known as the diamond frame. Frames must be strong, rigid and lightweight, which they do by combining different materials and shapes.
A frameset is made up of front and fork bikes and sometimes includes headsets and seat posts. Frame makers often produce frames and forks together as paired pairs.
Video Bicycle frame
Variations
In addition to the ubiquitous diamond frames, many different types of frames have been developed for bikes, some of which are still commonly used today.
Diamond
In diamond frames, the main "triangle" is actually not a triangle because it consists of four tubes: the head tube, the top tube, the bottom tube, and the seat tube. The rear triangle consists of a seat tube connected with a pair of fixed chains and a seat.
The headgear contains a headset, interface with a fork. The top tube connects the head tube to the seat tube at the top. The top tube can be positioned horizontally (parallel to the ground), or it may tilt downward toward the seat tube for additional cleaning. The bottom tube connects the head tube to the bottom bracket shell.
The rear triangle connects to the rear end of the fork, where the rear wheels are attached. It consists of a paired seat and chains tube in pairs and a fixed seat. The chain stays running connecting the bottom bracket to the tip of the rear fork. The chair stays connected to the top of the seat tube (often at or near the same point as the top tube) to the tip of the rear fork.
Step by step
Historically, the female bike skeleton has a top tube connected in the center of the seat tube rather than at the top, so the height stands lower. This is to allow riders to get off when wearing skirts or clothes. This design has been used in utility bikes to facilitate installation and decline for both genders, and is also known as step-through frame or open frame. Another force that achieves similar results is mixte.
Cantilever
In order for a cantilever bike, the chair keeps passing through the seat post and curved downwards to meet the bottom tube. Cantilever frames are very popular in bike cruisers, lowrider bikes, and wheelchairs. In many cantilevered frames, only the straight tube is the seat tube and the head tube.
Recumbent
The recumbent bike moves the crank to the front position of the rider and not below it, generally increasing the slipstream around the rider without the sharp bend typical of the waist used by the diamond frame bike racer. Banned from cycling in France in 1934 to avoid rendering bike-wearing diamond frames in racing, bike-making was supressed remained for half a century, but many models from various manufacturers were available in 2000.
Prone
The unusual bike moves the crank to the rear of the rider, producing a forward riding position.
Cross or girder
The cross frame consists mainly of two tubes that make up the cross: the seat tube from the bottom bracket to the saddle, and the backbone of the head tube to the rear hub.
Truss
Frame frame using additional tubes to form the frame. Examples include Humbers, Pedersens, and the ones depicted.
Monocoque
The monocoque frame consists only of an empty shell with no internal structure.
Fold
The folding bike frame is characterized by the ability to fold into a compact form for transport or storage.
Penny-farthing
The penny-farthing frame is marked by large front wheels and small rear wheels.
Tandem and sociable
Tandem and social frame support many riders.
More
There are many variations on the basic diamond frame design.
- Frames with no seat tube, such as Y-Foil Tracks, Zipp 2001, Airfoil Kestrel, and most frames by Softride.
- Topless tube frame like "Old Faithful" by Graeme Obree.
- Frames that use cables for members that are only under pressure, such as the illustrated Dursley Pedersen bike, Pocket Bicycle, Viva Wire 2009, Wire Bike from Ionut Predescu designer, or Slingshot Bicycles fold-tech series.
- Frames with circles replacing seat tubes, chain dwellings, and seats: called "roundtail".
- Elevated chainstay bicycles were very popular in the early 90s. It displays a rear triangle with a fixed bottom frame, negating the need for a chain to be pulled through the rear frame. This allows for shorter wheelbase and better handling during technical landings, at the expense of compromised integrity and resulting in lower flex bracket improvements (except reinforced) compared to frames with traditional chainstays.
This type of cycle article explains additional variations.
It is also possible to add couplers either during manufacturing or as a retrofit so that frames can be disassembled into smaller pieces for easy packing and travel.
Maps Bicycle frame
Frame tube
The diamond frame consists of two triangles, the main triangle and the rear triangle in pairs. The main triangle consists of the head tube, the upper tube, the lower tube and the seat tube. The rear triangle consists of a seat tube, and a fixed chain in pairs and a fixed seat.
Headgear
The head tube contains a headset, pads for the fork through the guide tube. In an integrated headset, the interface pads the cartridge directly with the inside surface of the head tube, on a headset that is not integrated bearing (in cartridge or not) interface with "cup" is pressed into the head tube.
Top Tube
The top tube , or cross-bar , connects the top of the head tube to the top of the seat tube.
In a traditional diamond geometry frame, the top tube is horizontal (parallel to the ground). In a compact geometry frame, the top tube usually tilts down toward the seat tube for additional additional clearance. In the framework of a mountain bike, the top tube almost always slopes downward toward the seat tube. The radically oblique top tube that endangers the integrity of traditional diamond frames may require additional gusseting tubes, alternate frame construction, or different materials for equivalent strength. ( See Road and triathlon bicycles for more information on geometry. )
The step-through frame usually has a top tube that tilts down to allow the rider to climb up and down from the bike more easily. Alternative step-through designs may include removing the top tube completely, as in the monocoque main frame design using a separate or hinged seat tube, and the twin top tube that continues into the rear fork ends as with the Mixte frame. Alternatives to this diamond frame provide greater versatility, though at the expense of additional weight to achieve equal strength and stiffness.
Control cables are routed along the mounts on the top tube, or sometimes inside the top tube. Most commonly, this includes wires for the rear brake, but some mountain bikes and hybrid bicycles also route the front and rear derailleur cable along the top tube.
The space between the upper tube and the crotch of the rider while straddling the bike and standing on the ground is called a permit. The total height from the ground to this point is called the height of the lever.
Down tube
The down tube connects the head tube to the bottom bracket shell. On a racing bike and some mountain bikes and hybrids, the derailleur cable runs along the bottom tube, or inside the bottom tube. On older racing bikes, the shift lever is mounted on the bottom tube. On newer ones, they are fitted with a brake lever on the handlebars.
The cage bottle holder is also in the lower tube, usually on the top side, sometimes also on the underside. In addition to bottle cages, small air pumps can also be mounted on these mounts.
The seat tube
The seat tube contains a bicycle seatpost, which connects to the saddle. The height of the saddle is adjusted by changing how far the seatpost is inserted into the seat tube. On some bikes, this is achieved by using the fast opening lever. Seatpost should be inserted at least a certain length; this is indicated by the minimum insertion .
The seat tube may also have a braze-on stand for a bottle or front derailleur cage.
Fixed chain
The chain remains runs parallel to the chain, connecting the bottom bracket shell to the tip of the rear fork or breaking. When the rear derailleur cable is directed partially along the bottom tube, it is also channeled along the fixed chain. Sometimes (especially on frames made since the late 1990s) mounting for disc brakes will be attached to a fixed chain. There may be a small buffer that connects the fixed chain in front of the rear wheel and behind the bottom bracket shell.
Fixed chains can be designed using tapered or non-tidy tubing. They may be relieved, ovalized, wrinkled, S-shaped, or elevated to allow additional clearance for rear wheels, chains, crankarms, or foot heels.
Fixed seats
The fixed seat connects the top of the seat tube (often at or near the same point as the top tube) to the rear fork dropout. The traditional frame uses a simple set of parallel tubes connected by the bridge over the rear wheels. When the rear derailleur cable is supplied partially along the top tube, it is also usually supplied along the seat of stay.
Many alternatives to traditional seating designs have been introduced over the years. The seat style that extends forward from the seat tube, under the rear end of the top tube and connects to the top tube in front of the seat tube, creates a small triangle, called Hellenic staying after the British frame builder Fred Hellens, they were in 1923. Hellenic chairs continued to add aesthetic appeal at the expense of additional weight. This seating style was popularized again at the end of the 20th century by GT Bicycles (under the "triple triangle" moniker), which has incorporated design elements into their BMX frames, as it also made for rigid rear triangles (advantages) in races ); These design elements have also been used on their mountain bike framework for the same reason.
Recently, a variation of the traditional seating that passes through the seat tube and connects further into the upper tube patented by Volagi Cycles. This frame element adds a length to the traditional fixed seat design, making it a softer journey on sacrifice frame rigidity.
Other common seating variants are wishbone , single seater , or mono stay , which joins together fixed directly on the rear wheel into a monotube that join the seat tube. A wishbone design adds vertical rigidity without increasing the lateral stiffness, generally an undesirable trait for the bike with the rear wheels not supported. The wishbone design is most appropriate when used as part of a rear triangle subframe on a bike with independent rear suspension.
A
The Fastback seat fills the seat tube in the back instead of the side of the tube.
In most seats, a bridge or brace is usually used to connect fixed on the rear wheel and under the connection with the seat tube. In addition to providing lateral stiffness, this bridge provides the mounting point for the rear brake, fenders, and racks. The seat itself may also be equipped with mountain brakes. Brake mounts are often absent in fixed-gear or track bike seats.
Shell under bracket
The bottom bracket shell is a short and large diameter tube, relative to other tubes in the frame, running from side to side and holding the bottom bracket. It is usually threaded, often left-hand threaded on the right side (drive) of the bike to prevent loosening with induced axle fretting, and threaded right on the left side (non-drive). There are many variations, such as the eccentric bottom bracket, which allows adjustment in the tension of the bicycle chain. These are usually larger, undivided, and sometimes separated. Fixed chains, seat tubes, and bottom tubes are all usually connected to the bottom bracket shell.
There are several traditional standard shell widths (68, 70 or 73 mm). Bicycles typically use 68 mm; Italian road bikes use 70 mm; Early model mountain bike using 73 mm; Further models (1995 and later) use 68 mm more often. Some modern bikes have a 83 or 100 mm shell width and this is for mountain biking or snowbiking special applications downhill. The width of the shell affects the Q factor or the bicycle's palm. There are several standard shell diameters (34.798 - 36 mm) with associated yarn pitches (24 - 28 tpi).
In some bike gearboxes, the bottom bracket shell can be replaced with an integrated gearbox or mounting location for a removable gearbox.
Frame geometry
The length of the tube, and the angle to which they are attached specifies the geometry frame . In comparing the geometry of different frames, designers often compare the angle of the seat tube, the angle of the head tube, the length of the top tube (virtual), and the length of the seat tube. To complete the bike's specifications for use, the rider adjusts the relative position of the saddles, pedals, and handlebars:
- high saddle , the distance from the center of the bottom bracket to the reference point above the middle of the saddle.
- stack , the vertical distance from the center of the bottom bracket to the top of the head tube.
- range , the horizontal distance from the center of the bottom bracket to the top of the head tube.
- lower bracket drop , the distance at which the bottom bracket center is below the rear hub level.
- handlebars , the vertical distance between the references at the top of the saddle to the handlebar.
- setback saddle , the horizontal distance between the front of the saddle and the bottom center bracket.
- standing height , height of upper tube above ground.
- front center , the distance from the center of the bottom bracket to the center of the front hub.
- overlapping legs , the number of legs that can interfere with the front wheel steering.
The frame geometry depends on the intended use. For example, a road bike will place the handlebars in a lower and further position relative to the saddle giving a more squatting up position; while the utility bike emphasizes comfort and has a higher handlebars resulting in an upright drive position.
Frame geometry also affects handling characteristics. For more information see the article on bicycle and motorcycle geometry and the dynamics of bicycles and motorcycles.
Frame size
Frame sizes are traditionally measured along the seat tube from the bottom bracket center to the top tube center. The typical "medium" size is 54 or 56 cm (about 21.2 or 22 inches) for a European male racing bike or 46 cm (about 18.5 inches) for a male mountain bike. A wider range of existing frame geometries has also led to other methods of measuring the frame size. Tour frames tend to be longer, while racing frames are more compact.
Bicycle and triathlon
Racing bike racing is designed for efficient power transfer with minimum weight and drag. Broadly speaking, the geometric of the road bike is categorized as traditional geometry with the top horizontal tube, or solid geometry with the top tube tilted.
Traditional geometry road frameworks are often associated with greater convenience and greater stability, and tend to have a longer wheelbase that contributes to both of these aspects. The compact geometry allows the top of the head tube to be above the top of the seat tube, lowering the height upright, and thereby increasing the clearance upright and lowering the center of gravity. Opinions are divided into the benefits of riding a compact frame, but some manufacturers claim that reduced sizes can fit most riders, and that it is easier to build frames without tubes of the perfect level.
Road bikes for racing tend to have a steeper seat buckle angle, measured from the horizontal plane. This aerodynamic rider position and can be spelled out in a strong stroking position. Trade-off is convenience. Touring and leisure bikes tend to have more traditional slack angle seat tubes. It poses more riders on the sitting bones and loses weight from the wrists, arms and neck, and, for men, improves circulation to the urinary and reproductive areas. With lazy corners, the designers stretch the chainstay so that the center of gravity (which would otherwise be further back on the wheel) is more ideal in the middle of the bike frame. Longer wheelbase contributes to effective shock absorption. In touring bikes and modern comforts, the corner tube seats are lazy, presumably to reduce production costs by avoiding the need to reset welding jigs in automated processes, and thus do not provide traditional or custom made comforts - Artificial frames that have angles the tubes feel more tilted.
The street racing bikes used in UCI-backed races are governed by UCI rules, which state among other things that the frames should consist of two triangles. Therefore a design that does not have a tube seat or top tube is not allowed.
Triathlon or time-trial special frames rotate the rider forward around the lower axis bracket of the bike as opposed to a standard road bike frame. This is to put the rider in a lower and more aerodynamic position. While handling and stability are reduced, the bike is designed to be driven in an environment with fewer group driving aspects. These frames tend to have steep tube-seat angles and low head tubes, and shorter wheelbase spacing for the correct range from saddle to handlebar. In addition, since they are not regulated by UCI, some triathlon bikes, such as Zipp 2001, Cheetah and Softride, have a non-traditional frame layout, which can produce better aerodynamics.
Track bikes
Track frames have much in common with the road and time trial framework, but come with horizontal fork edges facing back, rather than breaking, to allow one to adjust the rear wheel position horizontally to adjust the proper chain tension. Also the angle of the sitting tube is steeper than on a street racing bike.
Mountain bikes
For better ride comfort and handling, shock absorbers are often used; there are a number of variants, including the full suspension model , which provides shock absorption for front and rear wheels; and front suspensions are just models ( hardtail ) that handle only shocks that arise from the front wheel. The development of advanced suspension systems in the 1990s quickly resulted in many modifications to the classic diamond frames.
The recent mountain bike with a rear suspension system has a rotating rear triangle to drive the rear shock absorber. There are many variations of manufacturers in the design of a full suspension mountain bike frame, and different designs for different driving purposes.
Roadster/bike utilities
The roadster bike traditionally has sagging enough tubes and a 66-degree or 67-degree head-tube angle, resulting in a very comfortable and upright "sitting-and-ask" ride position. Other characteristics include a long wheelbase, up to 40 inches inches (often between 43 and 47Ã, inches, or 57Ã, inches for longbike), and long sweeping forks, often about 3Ã,¼ (76mm compared to 40mm for most road bikes). This frame style has a revival of popularity in recent years due to greater comfort compared to mountain bikes or road bikes. The variation on this type of bike is the "sport roadster" (also known as the "lightweight roadster"), which usually has a lighter frame, and slightly steeper seat tubes and about 70 to 72 degree tube angles.
Frame material
Historically, the most common material for bicycle frame tubes is steel. Steel frames can be made of various grades of steel, from very cheap carbon steels to higher quality and more expensive molybdenum alloys. Frames can also be made from aluminum alloys, titanium, carbon fiber, and even bamboo and cardboard. Sometimes, diamond frames (shaped) have been formed from other parts of the tube. These include I-beams and monocoque. Materials used in this frame include wood (solid or laminated), magnesium (I-cast beams), and thermoplastics. Some properties of relief materials decide whether it is appropriate in the construction of a bicycle frame:
- Density (or specific gravity) is a measure of how light or heavy the material per unit volume is.
- Stiffness (or elastic modulus) in theory can affect driving comfort and power transmission efficiency. In practice, because even very flexible frameworks are much more rigid than tires and saddles, driving comfort is ultimately more the choice of saddle, frame geometry, tire choice, and bike fit. Lateral stiffness is much harder to achieve because of the narrow profile of the frame, and too much flexibility can affect the transmission of electricity, especially through the scrub tires on the road due to rear triangle distortion, brakes rubbing on the rims and brushing the chain on the dental mechanism. In extreme cases, the gear can change itself when the rider uses high torque outside the saddle.
- The yield strength determines how much power is required to change the material permanently (for crash feasibility).
- Elongation determines how much material deformity allows before cracking (for accidental feasibility).
- The fatigue and endurance limits define the frame's durability when subjected to cyclic pressure from paddling or horseback riding.
Tubular engineering and frame geometry can overcome the many perceived shortcomings of these special ingredients.
Frame materials are listed based on similarity of use.
Steel
Steel frames are often constructed using various types of alloy steel including chromol. They are strong, easy to work, and relatively inexpensive, but denser (and generally heavier) than many other structural materials.
The classic type of construction for road bikes and mountain bikes uses standard cylindrical steel tubes connected with lugs . Lugs are fittings made of thicker steel pieces. The tube is attached to the lugs, which encircle the end of the tube, and then attached to the lug. Historically, lower temperatures associated with brazing (silver brazing in particular) have less of a negative impact on tube strength than high temperature welding, allowing relatively light tubes to be used without loss of force. Recent advances in metallurgy ("Air hardening steels") have created unaffected tubing, or which are even enhanced by high temperature welding temperatures, which have enabled TIG & amp; Las MIG to stop construction construction at all except some high end bikes. Overpriced bricked frame bikes have lugs filed by hand to fancy - both for heavy savings and as a sign of workmanship. Unlike MIG or TIG frames that are welded, a rugged frame can be more easily repaired in the field because of its simple construction. Also, since steel pipes can rust (although in practice paint and anti-corrosion sprays can effectively prevent rust), the fractured frame allows rapid tube replacement with virtually no physical damage to neighboring tubes.
A more economical method of bicycle frame construction is using a cylindrical steel tube connected with TIG welding, which requires no lugs to hold the tube together. Instead, the tube frame is properly aligned into a jig and stays in place until the welding is complete. Fillet brazing is another method for combining frame tubes without lugs. It's more labor intensive, and consequently less likely to be used for production frames. Like TIG welding, the fillet frame tubes are precisely formed or underestimated and then brass fillets are affixed to the joint, similar to heavy construction processes. Frame fillets can achieve more aesthetic unity (smooth curved appearance) than welded frames.
Among steel frames, using tubing tubing reduces weight and increases cost. Butting means that the thickness of the tubing wall changes from the thickness at the end (for strength) to be thinner in the middle (for lighter weight).
The cheaper steel bike frames are made of mild steel, also called high tensile steel, as may be used to produce cars or other public goods. However, higher quality bike frames are made of high-strength steel alloys (generally chromium-molybdenum, or "chromoly" steel alloys) that can be made into a lightweight tube with a very thin wall meter. One of the most successful oldest steels is Reynolds "531", molybdenum-manganese alloy steel. More common now is 4130 ChroMoly or similar alloys. Reynolds and Columbus are two of the most famous bicycle manufacturers. Some middle-quality bikes use this steel alloy only for some tubular frames. An example is the Schwinn Le tour (at least a certain model), which uses chromoly steel for upper and lower tubes but uses low quality steel for the remainder of the frame.
High-quality steel frames are generally lighter than ordinary steel frames. If everything is the same, losing this weight can improve the acceleration and climbing performance of the bike.
If the tube label has been lost, a high-quality steel frame (chromol or manganese) can be recognized by tapping it sharply with a flick of a finger. A high-quality frame will produce a ring like a bell where a high-quality steel frame will produce a dull dunk. They can also be identified from their weight (about 2.5 kg for skeletons and forks) and the type of lugs and forks used.
Aluminum alloy
Aluminum alloys have lower density and lower strength compared to steel alloys, however, they have a better strength-to-weight ratio, giving them an overwhelming weight advantage over steel. Early aluminum structures have proven to be more susceptible to fatigue, either due to ineffective alloying, or imperfect welding techniques used. This contrasts with some steel and titanium alloys, which have clear fatigue limits and are easier to weld or braid together. However, some of these drawbacks have been mitigated by skilled labor capable of producing better quality welds, automation, and greater accessibility to modern aluminum alloys. An attractive ratio of strength and weight of aluminum compared to steel, and certain mechanical properties, ensures it as a place amongst preferred frame-making materials.
The popular alloy for bicycle frames is 6061 aluminum and 7005 aluminum.
The most popular type of construction currently uses aluminum alloy tubes connected together with Tungsten Inert Gas (TIG) welding. Welded aluminum bike frames began to appear on the market only after this type of welding became economical in the 1970s.
Aluminum has different optimal wall thickness for tubing diameter of steel. It is the strongest about 200: 1 (diameter: wall thickness), while steel is a fraction of it. However, at this ratio, the wall thickness will be proportional to the beverage can, too fragile to the impact. Thus, the aluminum bike tube is a compromise, offering thickness ratios and wall diameters that are not of maximum efficiency, but giving us a larger pipe of aerodynamically acceptable proportions and good resistance to impact. This produces a much louder frame than steel. While many motorists claim that the steel frame provides a smoother ride than aluminum because the aluminum frame is designed to be more rigid, the claim is questionable validity: the bike frame itself is very rigid vertically because it is made of triangles. Instead, this argument calls the claims of aluminum frames having greater questionable vertical rigidity. On the other hand, lateral and twisting stiffness (torsional) increases acceleration and handling in some circumstances.
The generally recognized aluminum frame has a lower weight than steel, though this is not always the case. Low-quality aluminum frames may be heavier than high-quality steel frames. The butted aluminum tube - where the middle wall thickness is made thinner than the end - is used by some manufacturers for heavy savings. Non-round tubes are used for a variety of reasons, including stiffness, aerodynamics, and marketing. Different forms focus on one or another of these goals, and rarely achieve them all.
Titanium
Titanium is probably the most exotic and expensive metal commonly used for bicycle frames. It combines many desirable characteristics, including high strength and weight ratio and excellent corrosion resistance. Reasonable rigidity (roughly half of steel) allows for many titanium frames to be built with "standard" tube sizes comparable to traditional steel frames, although larger tube diameters are becoming more common for more stiffness. Titanium is more difficult for machinery than steel or aluminum, which sometimes limits its use and also increases the effort (and costs) associated with this type of construction. Because titanium frames are usually more expensive than the same steel or aluminum alloy framework, the costs incurred are unaffordable by most cyclists.
Titanium frames typically use titanium alloys and tubes that were originally developed for the aerospace industry. The most commonly used alloys on titanium bike frames are 3AL-2.5V (3.5% Aluminum and 2.5% Vanadium). 6AL-4V (6% Aluminum and 4% Vanadium) are also used, but are more difficult to weld, tube, and machine. Often, the tube is 3AL-2.5V while the break and other peripheral parts are made of 6AL-4V. The experimental frame has been made with commercially pure titanium (CP, i.e.:unalloyed), but this proves less durable for active riders devoted to this cost-level framework.
Extensive blows are also used to make low-weight tubes with acceptable stiffness. Early versions of Fat Chance Titanium (1992 and version 93) have tubes of different diameters welded together to create a more rigid bottom bracket area. The 1994 version has an external butted bottom tube.
The frame tube is almost always connected with Tungsten Arc Welding (GTAW or TIG) gas welding, even though the use of the vacuum has been used in the original frame. Several earlier titanium frames were made with titanium tubes bound to aluminum lugs, such as the Miyata Elevation 8000 and Raleigh Technium Titanium.
Carbon fiber
Composite carbon fiber is an increasingly popular non-metallic material commonly used for bicycle frames. Though expensive, lightweight, rust and strong, and can be shaped into almost any desired shape. The result is a frame that can be adjusted for specific strengths where needed (to withstand pedaling power), while allowing flexibility in other frame parts (for convenience). Customized carbon fiber bike frames can even be designed with strong individual tubes in one direction (such as the lateral), while corresponding in the other direction (such as vertical). The ability to design individual composite tubes with varied traits based on orientation can not be achieved with common metal frame construction in production. Some carbon fiber frames use a cylindrical tube that joins the adhesives and lugs, in a method somewhat analogous to the coarse steel frame. Another type of carbon fiber frame is produced in one piece, called a monocoque construction.
In a series of tests conducted by Santa Cruz Bicycles, it is shown that for the design of the frame with identical shapes and similar weight, the carbon skeleton is much stronger than aluminum, when it is subjected to the overall force load (bending the frame for both tensions). and compression), and impact strength. While the carbon skeleton can be light and strong, they may have less impact resistance than other materials, and can be prone to damage if falling or mismanaged. Cracking and failure can be caused by collisions, but also from incorrect parts of the attachment or mounting. These materials are also susceptible to fatigue failure, a process that occurs with use over long periods of time. Damaged carbon frameworks can be fixed, but due to security issues, it should be done only by professional firms with the highest standards possible.
Many racing bikes are built for individual experimental races and triathlons using composite construction because the skeleton can be formed with an aerodynamic profile that is not possible with a cylindrical tube, or will be very heavy on other materials. While this frame type may be heavier than others, its aerodynamic efficiency can help cyclists to achieve higher overall speed.
Materials other than carbon fiber, such as boron metal, can be added to the matrix to increase further stiffness. Some newer high end frames incorporate Kevlar fiber into carbon webbing to improve vibration damping and impact strength, especially in downhills and seat- and chainstays.
Thermoplastics
Thermoplastics are a category of polymers that can be reheated and rebuilt, and there are several ways that can be used to create a bicycle frame. One application of a thermoplastic bicycle framework is essentially a carbon fiber frame with fibers embedded in a thermoplastic material rather than a more general epoxy thermosetting agent. GT Bicycle was one of the first major manufacturers to produce thermoplastic frames with their STS System framework in the mid-1990s. The carbon fiber is woven loosely into the tube along with the thermoplastic fibers. This tube is placed into a mold with an inner bladder which is then inflated to force the carbon and plastic tube against the inside of the mold. The mold is then heated to melt the thermoplastic. Once the thermoplastic is cooled it is removed from the mold in its final form.
Magnesium
A number of bicycle frames are made of magnesium that has about 64% aluminum density. In the 1980s, an engineer, Frank Kirk, designed a new, fully molded frame consisting of blocks rather than tubes. A company, Kirk Precision Ltd., was established in the UK to produce road bikes and mountain bike skeletons with this technology. However, despite some initial commercial success, there were problems with reliability and manufacture of stops in 1992. A small number of modern magnesium frames in production were built conventionally using tubes.
Scandium
Some bicycle manufacturers make frames of aluminum alloys containing scandium, usually referred to only as scandium for marketing purposes even though Sc content is less than 0.5%. Scandium improves the welding characteristics of some aluminum alloys with superior fatigue resistance that allows the use of smaller diameter tubes, thus allowing greater frame design flexibility.
Beryllium
American Bicycle Manufacturing of St. Cloud, Minnesota, briefly offers a frameset made of beryllium tubes (bonded to aluminum lugs). Given the toxic nature of materials and prices ($ 26,000 for frames and forks), they never get caught. The report is that the trip was very loud, but the skeleton was also very laterally flexible.
Bamboo
Some bicycle frames have been made from bamboo tubes connected to metal or joints combined. Aesthetic appeal is often as much a motivator as a mechanical characteristic.
Wood
Some bicycle frames are made of wood, either solid or laminated. Although there are survivors of the exhausting 265 kilometers of the Paris-Roubaix race, aesthetic appeal is often the same as a motivator as a driving characteristic. Wood used for fashion bikes in East Africa. Cartons have also been used for bicycle frames.
Combination
Combining different materials can provide the desired stiffness, adherence, or attenuation in areas that are better than can be achieved with a single material. The combined material is usually carbon fiber and metal, whether steel, aluminum, or titanium. One application of this approach includes a bottom tube of metal and a fixed chain with carbon top tube, seat tube, and fixed seat. Another is a major metal triangle and a fixed chain with only fixed carbon sit. The carbon fork has become very common on racing bikes of all frame materials.
More
This type of bicycle article explains additional variations.
Butted Tubes
Butted tubing has increased the thickness near the joint for strength while keeping the low weight with a thinner material elsewhere. For example, a sheet of three means a tube, usually of an aluminum alloy, has three different thicknesses, with a thicker part at the end where they are welded. The same material can be used on the handlebars.
Braze-ons
Small features - bottle hole installation, shifter boss, cable stoppage, pump pegs, cable guides, etc. - described as braze-ons for initially, and sometimes still, brazing.
Suspension
Many bikes, especially mountain bikes, are suspended.
See also
References
External links
- Cycling Science: Frames & amp; Material from Exploratorium
- Sheldon Brown "Revisionist Theory of Bicycle Sizing" - an explanation of the various ways of measuring frame sizes.
- Frame Size Calculator - simple frame size frame calculator for the bike path
- Metallurgy for Bicycle Riders - discusses the nature of frame materials in relation to suitability for framing use
- The BikeCAD program allows you to design your own frames online.
- Frame Sketcher is a simple HTML5 app that makes it possible to sketch and compare frames online.
Source of the article : Wikipedia
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