Jennifer Erickson
HPV – Chassis
Manufacturing Division
(970) 407-0767 je191499@engr.colostate.edu
Table of contents:
Introduction .......................................................................................................... 1
Materials .............................................................................................................. 1
Steels ............................................................................................................ 1
Aluminums.................................................................................................... 3
Titanium ........................................................................................................ 4
Composites .................................................................................................. 4
Tube Forming ...................................................................................................... 6
Mitering ......................................................................................................... 6
Fine Blanking ............................................................................................... 6
Bending ........................................................................................................ 6
Characteristic Tubes ........................................................................................... 7
Welded Tube ................................................................................................ 7
Seamless Tube ............................................................................................ 7
Elliptical, Airfoil, and Square Tubes ............................................................ 7
I - Beams ...................................................................................................... 7
Joining ................................................................................................................. 8

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Contacts ............................................................................................................ 12
Suppliers ..................................................................................................... 12
Welders ...................................................................................................... 12
Heat Treatment .......................................................................................... 12
Machining material and extras .................................................................. 12
Seat foam ................................................................................................... 13
References ........................................................................................................ 13
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The bicycle has been a form of transportation, sport, and exercise for over two centuries.
Now, more than ever, its popularity is high and research is consistently being done to keep up with the competitive demands. The material properties and manufacture process involved with that material are two important categories when in the analysis phase of bicycle design. Researches from past iterations of the bike have narrowed the material selection down. There have been factors that have been proven to work and most bicycle manufacturers have chosen to use the proven materials and manufacturing processes because of their cost effectiveness. Research will still go on to design the ultimate bike material with the fastest manufacture and strongest joints. Meanwhile, this document helps describe the factors involved with the material selection for a bike or human powered vehicle frame.
Every style of bike is different. Mountain bikes are made to be somewhat rigid and light, but still needs suspension to smooth out the rough ride of a trail. Slalom bikes are not made to be lightweight, but instead are thick and strong and contain complex suspension for the fast downhill runs. Road bikes are designed to be as lightweight as possible and rigid to utilize the power out of every stroke of the rider. The criteria of the Human
Powered Vehicle are based off of the rules set for the competition. The bicycle must perform in various events that effect the frame diversely. The challenge of designing the
HPV for a competition of various different types of races that goes to an overall score.
Some of the subjective criteria of a fully faired HPV are that it needs to be rigid, strong, manufacturable, tolerant of continual impact, but does not necessarily need to be aerodynamic due to the fairing surrounding it.
The materials for a human powered vehicle are influential to the performance of the bike.
Several material categories have proven to be the better materials for the criteria of the designs. These categories are steels, aluminums, titanium and composites.
Steel is an iron/carbon alloy that, with the addition of several elements such a s chrome, nickel, manganese, molybdenum, vanadium, etc., develops specific characteristics such as tenacity, fatigue resistance, workability and insensitivity to overheating.
14 The most commonly used frame material is steel. This is probably due to several reasons. First, steels have yield strengths ranging fro 90,000 to 170,000 psi and ultimate tensile strengths ranging fro 100,000 to 190,000 psi. This is significantly higher than most aluminum and

titanium alloys.
6 “The reason tensile strength is so important is because it allows the manufacturer to draw a lighter, thinner tube. This allows steel to remain competitive with other, less dense, frame materials. In addition, a higher tensile strength tube will deform farther before failing.” 
Steel also has a high modulus of elasticity, which is a measure of the stiffness, or rigidity, of a material. This means that smaller diameter tubing can be used, which is more aerodynamically and specially desired. The resiliency of steel makes it a good choice for bike frames because the material will yield, or stretch, when it is subjected to high local stress. This allows other parts of the frame to assume the load without causing failure.
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The majority of bicycle tubing falls into one of three groups of alloys: chrome-molybdenum
(chrome-moly), manganese-molybdenum, and nivacrom.
Adding chromium and molybdenum to steel will increase its strength, hardness, and wear resistance. This means that chrome-moly is stronger than plain carbon tubing with the same carbon content.
12 Less material is needed to make a reliable frame. The lower carbon content in Chrome-moly allows the frame tubes to be joined by TIG-welding. This eliminates the need for reinforcement sleeves, or lugs, in the joining process.
6 A specific type of chrome-moly that is alloyed with nickel to improve strength characteristics cannot be brazed or TIG-welded. Instead, this material requires adhesive bonding to join the frame tubes together. Chrome-moly is denoted as 41xx series steels and has 0.5 - 0.95% chromium and 0.13 - 0.20% molybdenum. Adding nickel to chrome-moly develops the
43xx and 86xx series alloys. Nickel will increase the elastic limits, hardenablility, impact and fatigue resistance from the 41xx series chrome-moly.
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Adding manganese alone creates the 13xx series that have higher strengths and hardenabilities then plain-carbon steel. Molybdenum alone creates the 40xx series.
Molybdenum also increases the strength and hardenability. The best use of this alloy is to inhibit diffusion to slow down the rate of coalescence of the Fe
3
C.
9 Manganesemolybdenum tubes are usually formed be seamless drawing and can be drawn to thinner gauges because of their high tensile strength (190,000). This material is often heattreated to increase strength. Care must be taken so that the brazing temperature is not to high because the joints would anneal (soften). This would reduce the advantages of using heat-treated materials. For this reason, TIG-welding is not recommended. If the tubing is of a very thin gauge material that has been heat-treated, a method of joining that uses silver solder may be required to assemble the frame, instead of brazing.

Figure 1 (11)
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Alloying vanadium, niobium and chromium with steel forms Nivacrom tubes. It is specifically designed to make tubes for bicycle frames. It has the advantage over other steels of combining extremely high mechanical characteristics with great tenacity in the welding area. “The alloy elements, vanadium and niobium, precipitate in the metal matrix blocking the grain growth and blocking the resulting decline in the mechanical characteristics.” 8 Nivacrom tubes are probably formed by seamless drawing, but its resistance to grain enlargement may allow seamed tubing to be used. Joining processes should include TIG-welding and brazing. This material does not require heat-treating, as it can be strengthened by mechanical drawing.
3 A spin-off of nivacrom it a recent material discovery called thermacrom from Columbus metal manufacturers. It is steel alloyed with manganese, chrome, molybdenum and vanadium. These elements produce an increase in temperability, which allows fine-grains after welding. It withstands fatigue stresses and has better characteristics of strength, tenacity, corrosion and wear compared to nivacrom
(see Figure 1).
11 It may be the future of bike materials.
The asset that Aluminum has over steels is its low density. Aluminums density (0.098 lb/in 3 ) is approximately 1/3 the density of steel (0.283 lb/in 3 ).
6 The improved corrosion resistance of aluminum has also helped with its increase in popularity. However, the ultimate tensile strength of aluminum is only 45,000 psi (steels is almost three times larger). In addition, the modulus of elasticity of aluminum is only one third of the value for steel. Aluminum will eventually fail in a brittle manner instead of a ductile. This means that it will break instead of bend. Over sizing the tube diameters can reduce or alleviate these failures. This over sizing will stiffen the tubs and compensate for the low modulus of elasticity. If the structure is stiffened to the point of no flex, the fatigue problems are eliminated.
4 Oversizing aluminum tubing will not increase the weight of the frame due to its low density.
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There are limitation to aluminum that should not be overlooked. First, aluminum frames are not as easy to repair as steel frames. Minor misalignments can be fixed by cold setting , “but not without risking premature failure, even if there’s no visible damage.” 2 If aluminum frames are heat-treated, then tubes can no longer be replaced by welding or brazing because the strength of the joint is lost by the ‘re-heating’ process. Second, the design of the aluminum frame is so critical that it’s difficult to custom build to customer’s requests. Finally, aluminum needs processing and manipulation that are not found in traditional frame building. Assembly often requires special lugs that are costly to produce and these lugs will be different for each frame size.
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Different alloying elements can be added to aluminum, but for bicycle frames, only three main types are used: magnesium, magnesium and silicon, and zinc. Seamless drawing, in general, probably forms aluminum tubing. However, the heat-treating and joining processes used tend to be very alloy specific. For example, 5086, which is the most common magnesium alloy, cannot be heat-treated at all.
4 But, it is very tolerant to welding and has good post-weld strength when compared with other aluminum alloys.
11 The most commonly used magnesium and silicon alloy, 6061, is usually heat-treated to improve its strength. It is also tough enough to be welded. The drawback with this material is the complicated post-weld treatment that is required.
4 Most zinc alloy tubing, on the other hand, cannot be joined by welding. Instead, the tubes must be adhesive bonded together 3 . Zinc alloys that are weldable require an aging process after the welding process is complete. “This can, in most cases, be achieved at ambient temperatures over days or weeks or be done artificially in an oven in a matter of hours.” 4
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The ultimate tensile strength of titanium alloys range from 90,000-150,000 psi, while the yield strength ranges from 75,000-130,000 psi. However, the density of titanium is only half as much as steel. This, in combination with the high ultimate tensile strength, gives titanium alloys a good strength to weight ratio. The modulus of elasticity for titanium is rather low, indicating that titanium frames will only be half as stiff as steel. However, shape and geometry will significantly affect the rigidity of metal tubes. This means that simply over sizing the tubes with only a slight increase in frame weight can increase the rigidity of titanium tubing. Titanium has the best fatigue strength of all the materials currently used in frame building.
16 In addition, some of the recently introduced titanium alloys are more ductile than previous alloys. These new alloys will, “make titanium bikes more ductile so they yield before they break and easier for a builder to form and assemble." 16 And because titanium has a low coefficient of thermal expansion, joint strength will be maintained even when welding is used during the assembly process. But, by far, the best selling attribute of titanium is its corrosion resistance. This means that the life of the bicycle frame is increased while regular maintenance is significantly decreased.
The one major drawback for titanium alloy frames is the difficulty of producing the frame.
First of all, titanium is very expensive and difficult to obtain. Many of the titanium tubes that are currently used i n bicycle frames were designed, “for carrying corrosive chemicals or for high-pressure piping in nuclear reactors. Frame builders must design around these diameters and wall thickness, often compromising performance in the process.” 13 In addition, the actual process of joining the tubes can be rather difficult. Titanium welding must be done in a clean and inert atmosphere because it will absorb oxygen and become brittle at temperatures above 400 degrees C.
16 This will jeopardize the joint strength of the frame. “Contamination of any kind will lead to brittle failures; even a finger print will lead to a failure.” 16 Machining of titanium is also harder and more time consuming than other materials. Titanium will gall and smear, and cutting temperatures may reach critical values because the material is so hard. Because of this, “cutting must be done with sharp cutters and at comparatively low speeds." 16 Titanium alloy tubes may be formed by seamless drawing. Joining processes include welding (with higher Argon gas consumption), welding with an electron beam in a vacuum room, and brazed lugs. Some titanium alloys can also be annealed and cold-worked to relieve residual stresses.
16
Reinforced plastics, with fibers of carbon or Kevlar are an application that may become the bike material of the future. These materials have become popular enough that they are reasonably priced, and their tensile strengths and Young’s Modulus are better than that of steel. However, one drawback is the quick fracture of these fiber materials. Unlike steel, they do not stretch before fracture, causing sudden failures. Significant detail has to be put into the design with fiber-reinforced composites due to the difference in material properties depending on the direction and stacking procedures of fiber. Bicycle manufacturers use many new high tech materials to improve their products. Stronger, lighter, better handling bicycles result from careful material selection. Composite materials offer manufacturers the ability to tailor material properties to their needs. Material properties of composites depend upon the fiber and matrix materials and especially the manufacturing process.
Manufacturers most commonly produce tubes by pultrusion and filament winding.
Pultrusion creates composites with fibers aligned along the length of the tube.
15 Although useful in many applications, uni-axially aligned fibers are inappropriate for the combined loading applied to a bicycle frame. Filament winding processes use continuous fibers. The fibers pass through a resin impregnation bath and wind over a rotating or stationary
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mandrel. Fibers wind onto the mandrel in a helical pattern of successive layers at a constant or varying angle. New advanced composite manufacturing methods can wind the main frame triangle as one piece. Additionally, seat stays and chain stays can be wound as single pieces. The three main triangles are then wound together while integrating the seat and head tube.
14 Current applications of composite materials include frames, handlebars, forks, seat posts, and seat and chain stays. Tube shapes vary from round or elliptical to rectangular or even triangular geometries. Filament wound carbon fiber, Kevlar fiber, or E-Glass comprise handlebars. Some manufacturers build seat posts and forks from carbon fiber, Kevlar and epoxy composites.
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Mitering is the process used to cut the end of a tube to fit the other tube/s in a joint. The cut is usually a circular concave cut. The goal of this process is to make a tight fit to assist with the joining process. Mitering is usually preformed in two ways; machining and laser cutting. Machined miters are usually preformed on a mill with a hole saw. This way ensures a cold cut but allows some deformation of the tube due to the high forces. Laser cutting creates a high quality edge because it produces a dense and tight beam that only effects a small area. Laser can also be controlled robotically.
9 Both Cannondale and Trek are a few of the manufacturers that use laser cutting as a production tool.
In the fine blanking process, a punch and a die are used which are the shape of the dropout being formed. A stinger or impingement ring on the upper pressure pad holds the sheet metal tightly against the blanking die. The blanking die then presses the plate through the die. A lower pressure cushion is used on the underside of the work piece to prevent distortion of the part. The edge quality and flatness of the part are better with the fine blanking process than with conventional blanking, which does not use the stinger or lower pressure cushion. Holes in the part can be punched at the same time. A hydraulic press is used to move the punch, pressure pad and die.
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The tubular shape brings up a more complex bending activity than sheet metal. A form block must be used for tubes. There are at least two types of bending styles; compression bending or draw bending. In compression bending the tube is wrapped around a solid form block by a wiper shoe while being clamped at the other end. Draw bending uses a rotating form and a bending die with a clamp on the end that is stretching.
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The shape and geometry will become a major factor in the selection of the tube or geometry to be used on the HPV. The wall thickness and outer diameter affect the rigidity, strength and weight. Increasing the thickness of the tube only affects rigidity, strength and weight by a factor of one. Increasing the diameter of the tube increases the rigidity of a factor of three, the strength by a factor of two, and the weight by a factor of three.
Although decreasing the thickness can then reduce the weight, tubes that are too thin will buckle. Buckling occurs when the wall thickness is 1/50 the diameter of the tube or less.
There are two types of tubes on the market for bicycle frames; the welded tube and the seamless tube. Beyond that it is possible to use other types of shapes like a square, triangular, or elliptical tube or an I-beam. This section will cover how these options are manufactured and why they would be used on the HPV.
Cold working a rolled strip into a round form is how welded tubes are begun. The seam between the two edges is electrically welded continuously and a process called untwisting reduces the excess weld bead. After untwisting, the beam in put through calibration process by moving through shaped rollers. This type of tubing is not made with the high end steels, aluminums or titanium. Usually chrome-moly tubes will be welded tubing. It is a strong, but heavier tubing that is used for more touring and forgiving applications.
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The advantages of seamless tubes are great, but it is much more complex to manufacture. Taking a billet made from continuous centrifugal casting, the billet is heated in a rotary-hearth furnace to 1200

C. Once it is hot, it is sent to the perforating rolling mill that compresses it between two oblique rollers that drill through the central section. This part of the process produces a roughly drawn tube that needs to be redrawn to make a final piece. Seamless tubing is used on the very best range of materials. The advantage of using seamless tubes over any other tubes is that it can produce optimal tubes for any bike. There are variable thickness tubes so that the thickness can be larger where the weld is without effecting the small thickness of the rest of the tube.
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Round tubes are ideal for multi-directional stresses because the consistent shape will distribute the loads evenly from any direction, but there are some applications where other geometries can play an important role. Elliptical tubing is best used when there are more stresses in one direction than in the other. The major axis will resist bending 40 – 50% better than round tubes, but rigidity along the minor axis is decreased by 75%.
6 Along the lines of an elliptical tube are the aero tubes. These tubes are shaped like and airfoil. The application of the tube is basically for an increase in aerodynamics from the blunt circle, but does not have an improvement effect on the mechanical properties. A square tube is not the optimal tube for cycle applications. It uses much more material to make it strong, but not optimally loaded member.
The use of I beams in a bicycle is not usually suggested, but there is possible applications in a stand-up bike and HPV. Kirk precision uses this design in their racing bikes and it
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works because it is a die-cast, solid piece made of a magnesium alloy. The design is comparable in weight to other chrome-moly frames, but increases the torsion stiffness by
50%.
3
The joining process can be accomplished be several ways. The process needs to be chosen based off of the properties of the material being joined
Arc welding where two materials are fused due to recrystallization. The filler rod material must have a similar melting point as the two materials being joined. In welding, a shielding agent must be used to prevent oxidation and other corrosive atmospheric effects. Most commonly this would be an argon-based gas. Tungsten Inert Gas welding (TIG) is the most used form of arc welding for bike frames. It can utilize a low current to avoid burning
through thin tubing applications.
Figure 2 18 : Tig Welder
Brazing is a process where filler metal is melted and re-solidified between two solid pieces of metal.
The major difference between brazing and welding is that the melting point of the filler material is about half that of the base metal. As with welding, brazing requires the use of a shielding agent.
7 Common filler materials used in bike manufacturing include brass and silver. Two major types of brazing are used in frame manufacturing. The first method uses lugs. This lug holds the more than one tube together. Lugs are brazed onto the tubes and facilitate against buckling in the tubes. Capillaries distribute the filler material to the joint. Fillet brazing (braze welding) is the second most common type of brazing. Fillet brazing uses a heat source to melt the flux to fill the joint.
Fillet brazing does not use capillaries to distribute the flux to the joint, but relies on the build-up of the filler material. “The most useful type of brazing is torch brazing. The torch heats up the flux and filler material and the joint is bonded. Most steels and aluminum alloys can be brazed by this technique. Other brazing techniques include furnace and diffusion brazing. Furnace brazing heats up the entire work piece and sets the filler and flux around the joint. Diffusion brazing is similar to furnace brazing except it is left in the furnace for an extended time to allow for diffusion to occur. Diffusion and furnace brazing are more applicable to joining more exotic materials such as titanium alloys. The most commonly used filler materials for bike brazing are brass and silver alloys.” 7
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“Adhesive Bonding Technology (ABT) can be used on a wide range of materials. ABT is similar to brazing except an adhesive is used to bond the tubes with the lugs. There are three basic types of adhesives used to bond bike frames; natural adhesives, inorganic adhesives and synthetic organic adhesives. Synthetic organic adhesives are used throughout manufacturing because of their load-bearing applications. Some examples of these synthetic organic adhesives include epoxies, polyurethanes, acrylics, silicones and cyanoacrylates. ABT bonded bikes are manufactured the same way as the lug brazing technology. The head and bottom bracket tubes are aligned using a jig setup. Next, the tubes are cut and inserted and the adhesive is applied and set to dry. The use of ABT’s in the joining and manufacturing of bike frames can be quite advantageous. The first major advantage is the savings in weight of ABT over welding and brazing. Another advantage is the increased load capability, sealing, corrosion resistance and vibrational damping characteristics of the bonding material.
Another advantage is that the frame tube properties will not be altered or deformed by heat. The trade off is a decrease in strength, but can be accounted for with the optimal lug design. Due to adhesive curing times this technology is more expensive and is more popular with the upper grad e and customized bikes.” 7
Figure 3 19 : Example Erickson Lugs
As mentioned previously, the Human Powered Vehicle competition has criteria that limit our design in differing ways from most bicycle designs. The basic rules say that the vehicle must be 1/3 faired. We decided to create a full fairing for the aerodynamic benefits when competing. Therefore, the vehicle must be inherently stable. We decided to build a recumbent trike that was stable and fully faired. This trike would be designed for the tadpole configuration with two wheels in the front and one in the back. The back wheel would be driven and braked while the front wheels would be steered. For optimal power output of the rider we would set them with a 30 degree angle from the horizontal axis to the back and a 20 degree angle from the horizontal axis to the feet. To reach high speeds, such as 50 mph, the fairing must have a frontal area of less than 5.5 ft^2. The chassis must be designed to fit the constraints of the rider and the fairing while maintaining the criteria set for the frame structure.
With these constraints in mind, the chassis could be designed to be rigid, strong, somewhat light and durable. A space truss type design was applied for rigidity. This design was bulky and had many tubes. Therefore optimization of the material selection was necessary. Initially, Nivacrom was the ultimate material for the job. This avoided the complexity of joining Titanium and the heat-treating of aluminum. As the semester proceeded, Nivacrom was pulled out of the design due to the high price (approximately 4.5
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times more expensive than chrome-moly). Our budget was limited, so we went with chrome-moly for budgeting reasons.
The tubes were prepared by attaching hole saws on the milling machine. A drill press could also be used, but due to our lack of experience, the mill’s vice achieved a much safer structure to hold the tubes. Also, we could slowly bring the base of the mill with the vice and tubes up into the rotating hole saw. This seemed to create more control of the speed of cut than pressing the hole saw down into the tube. The speed of cut can be a major contributor to poor cuts and broken hole saw teeth. The mill should run at around
660 rpm. Ultimately, the hole saw should be used with an attachment that can be held in the mill by a cullet. The hole saw attachments that fit into a chuck also work well and are more available. It may be necessary to tighten the chuck between cuts. Do not use cutting grease with the hole saws, they are designed to be dry. The hole saws themselves must be carbide tipped for cutting through steel. These can be ordered from Moser
Machine Tool Supply Inc. Their contact information is in the “Contacts” section of this document. Placing a protractor on the horizontal surface of the vice and setting the scale to measure the angle can measure angled cuts. This would get the tube in the correct angle to a tolerance of a degree. When using a flat cut, a chop saw did the best job.
The tubes must be prepared between the mitering and welding stages. To do this, it may be necessary to use acetone to remove all grease and impurities. Cleaning the tubes ensures that the weld bead will be much more pure and strong. De-burring the miters and cuts by using a sander makes joining much easier and protects skin from small cuts.
Polishing the ends was also found to be helpful in creating a clean end, but was definitely not necessary, particularly if you already used acetone.
The chrome-moly could be joined using a TIG-welder and small 880-T stainless steel filler rod. With use of a jig to hold each tube, the tubes could be strongly tacked and then the frame could be pulled out of the jig for further welding. The frame building process was a slow iteration, but produced a rigid, strong and durable frame.
The time it takes to make the frame can be cut down by the approach taken. Trouble incurs when “working ahead.” Only prepare the next tube to be welded. Cutting all the tubes ahead of time will encourage large gaps, bad fits, dissymmetry and stresses in the frame. Preparing each tube previous to welding will allow for perfect fits. If this frame style were to go into production, some major manufacturability changes would have to be made. The frame design would have to become much simpler. This frame had around
46 feet of tubing on it. There were around 60 welds. Around 180 combined hours were put into making this frame. This is a ridiculous amount of time. We are only making two frames, there would have to be manufacturing changes if more were being made. The run time would decrease with experience, but the hours are still really high for one product.
Using a different material could have added time to the process. The advantage of using chrome-moly over any other material is that it is strong and easy to manufacture. It is a great material to practice on. It is also the least expensive material of all the ones mentioned earlier. For this type of race where there are no hill climbs and many drivetrain parts, steering parts, a hefty seat and a large fairing, the weight was not as much as an issue. We could get away with using chrome-moly. In any other situation it may not be as effective.
To re-iterate, the suggested path to manufacturing the HPV would be to:
(1) Use chrome-moly tubing, approximately .035 inches in thickness.
(2) Miter with hole saws on a milling machine.
(a) Use carbide tipped hole saws.
(b) Do not use cutting oil.
(c) Run at approximately 660 rpm.
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(3) Use a TIG welder with 880-T stainless steel filler rod.
(4) Cut tubes only before they are welded for a proper fit.
(5) Employ a Jig to hold the tubes accurately and symmetrically.
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Aircraft Steel
Jack Zweck
923 Weld County Road #7
Erie, CO 80516
Black Sheep Fabrication
James Bleakley
(970) 493-1921
Easton Sports, Inc. (aluminum)
Sean Walters (director of sales)
(818) 782-6445
7855 Haskell Avenue
Suite 200
Van Nuys, CA 91406-1999
Colorado Iron and Metal, Inc. (sheet and stock metal)
(970) 482-7707
1400 East Mulberry,
Fort Collins, CO 80524
Black Sheep Fabrication
James Bleakley
(970) 493-1921
Kevin Lee
(970) 472-8184
Thermal Specialties
(970) 532-3796
305 Turner Ave.
Berthod, CO 8----
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Rocky Mountain Adventures
(970) 493-4005
1117 N. U.S. Hwy 287
Fort Collins, CO 80524
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2) Cycling Plus, Steel – Http://www.futurenet.co.uk/,inkas, laststar,/outdoors/cyclingplusMetal/Steel.html
3) Kukoda, John, “Materials update; the present and future of nonferrous frames,”
Bicycling, May 1988, v29, n4, p90.
4) Cycling Plus, Aluminum – http://www.futurenet.co.uk/,inkas, laststar,/outdoors/cyclingplus/Metal/Aluminum.html
5) Redcay, Jim, “Bicycling’s Titanium Project; How We Built a Roadworthy 15-Pound
Bicycle,” Bicycling, April 1988, v29, n3, p166.
6) Herman, Rebecca, “Materials and Tube Geometry”, MSM 481 Project Bicycle: Frame
Team.
7) Oram, Shanti, “Joining”, MSM 481 Project Bicycle: Frame Team.
8) Brandenberg, Kristin and Defever, Sherri, “Composites”, MSM 481 Project Bicycle:
Frame Team.
9) Schey, John A., Introduction to Manufacturing Processes, 2 nd Edition, McGraw-Hill,
Inc., 1987.
10) Kalpakjian, S., Manufacturing Engineering and Technology, 3 rd Edition, Addison-
Wesley Publishing, New York, 1995.
11) Columbus homepage, steels, http://www.columbustubi.com/english/acciaio/conoscere.html
12) Smith, William F., Structure and Properties of Engineering Alloys, 2 nd Edition,
McGraw-Hill, 1993.
13) Kukoda, John, “in Praise of Steel; Fiber’s Important, but Chrome-moly is Still the Main
Course,” Bicycling, July 1988, v29, n6, p110.
14) Wound Up http://www.redrocks.com/products/woundup.html
.
15) Chawla, Krishan K. Composite Materials: Science and Engineering. Springer-Verlag.
New York, 1987.
16) Cycling Plus, Titanium – http://www.futurenet.co.uk/,inkas, laststar,/outdoors/cyclingplus/Metal/Titanium.html
17) Reynolds Home Page – http://www.veloworks.com/rivendell .
18) Anionics Inc. Page - http://www.anionics.com/tig_weld.html
19) Erickson Cycles Page - http://www.sandsmachine.com/bp_erick.htm
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