Materials selection of a bicycle frame using cost per unit property and digital logic methods January 2010 International Journal of Mechanical and Materials Engineering 5(1):95-100 Early frames were described as “noodly” because they used similar tubing dimensions to the more traditional steel – the change in material stiffness hadn’t been taken account of and they flexed significantly. Woven pre-preg may be used as an impact resistant top layer and to give a better surface finish. Carbon frame ride can be controlled in much more detail by varying the layup in different areas of the frame to tailor for compliance or stiffness. Usually, Grade 9 Titanium is used for bike frames. The material that frame is made out of has a dramatic effect on the way it rides, its durability, and cost. Young’s Modulus is similar for metals made from the same alloy. It means that, unlike with metal, a frame tube can have different characteristics along its structure. Frame And Fork Materials: Fine frames are built from a myriad of materials. However many manufacturers do offer crash replacement programmes. It resists loads in all directions. We don’t use pure iron (steel is a mixture of iron and carbon), pure aluminium or pure titanium. These properties can be seen in Table 1. Repeated loading of materials can lead to fatigue failure. Most manufacturers now use pre-preg carbon; sheet of carbon fibres that are pre-impregnated with resin. The design of frames must be carefully considered to withstand real-world scenarios and loading. In the past material and production limitations restricted the minimum wall thickness achievable with steel. For example a double butted modern steel tube may be 0.7mm at either end but 0.4mm along most of the length of the tube. In practical use the different alloys will be indistinguishable, though 7005 is slightly cheaper to work with as it requires less overall processing. To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser. In contrast metals act like springs and have no significant damping. The main property of importance for bike frame design is Young’s Modulus. The ability to repair steel can often be overlooked. Because carbon fibers are pliable in one direction and stiff in the other, sheets can be layered to make different parts of the frame react differently. To maintain the same stiffness for a lighter weight, we could use less material in a larger diameter, thinner walled tube. Figure 4.1: Common bicycle frame materials The materials used for mountain bicycle frames have a wide range of mechanical properties. The fibres have diameters down to 5 micrometres, much thinner than a human hair. What some people describe as dead feeling, others exult as hugely comfortable. A frame may use hundreds of individual pieces. It is potentially more difficult to identify damage with a carbon frame – where a metal frame will have bent, a carbon frame may have cracks that may not be visible. However material toughness is essential in ensuring damage resistance. A workhorse … The theoretical analysis is according to the fourth metal material … Our sister site for e-bikes... ebiketips.co.uk, Pros and cons of carbon, steel, aluminium and titanium, Shimano M8000 XT 11 Speed Cassette - 11-46 / 11 Speed, Mavic Crossride Tubeless Pulse 27.5" Front Wheel (WTS) - 15mm x 100mm, Northwave Flash GTX Winter Boots - 41 Black | Cycling Shoes, Shimano XT M8000 Shadow+ Rear Derailleur - 11 Speed - Medium Cage GS, Mobi V-17 Portable Bike Pressure Washer - Blue - Grey, Blue - Grey, Shimano XT M8000 11sp Rear Derailleur - Black - Long Cage, Black, Hope Tech 3 E4 Brake - No Rotor - Red - Left Hand - Front, Red, RockShox Recon Gold RL Solo Air Forks - Boost - Matte Black - 140mm, Matte Black, Maxxis Aggressor MTB WT Tyre - EXO - TR - Black - Folding Bead, Black, Maxxis Minion DHF Wide Trail Tyre (3C-EXO-TR) - Black - Folding Bead, Black, Watch Lil' Robbo take a break from the usual 9-5, Progressive frameset on test, plus suspension from DVO, Incredibly light and very well priced, but max insertion limit may not work for your bike, A brand new DH certified helmet with a removable chin guard, Fun and fast with a well-specced frame, but decent stop and go bits would add more than the gimmicky geo adjust, Excellent tyre for UK winters and natural trails, but can be draggy, Top scoring wheelsets you can buy for your gravel bike in 2021, Effective and easy to use, though the bottle can be awkward. One of the unique abilities of carbon fibre is its ability to damp vibration. deflect under load providing additional comfort. One important thing to keep in mind is that we are optimizing the material properties to fit your priorities for your custom bike frame. It should be noted that the ability to soak up “road-buzz” is not really related to the ability to absorb larger shocks or impacts. It is quite natural to be so, since poor quality steel is an obsolete material (however the story is radically different with hi-quality steel), carbon can be expensive sometimes and titanium is not so easy to find. 2009 ASME Human Powered Vehicle Competition Drexel University Philadelphia PA DESIGN REPORT Olin College Human Powered Vehicle Helios CONTENTS, Embedded systems training in bangalore .docx, THE ENERGY APPROPRIATE PERSONAL COMMUTER VEHICLE, MECHANICAL ENGINEERING DESIGN II: Product Development Project, Electrical Scooter (Mechanical Engineering Design 1 UiTM). At the very core of every bicycle, there is a frame. Steel will rust if neglected – though frames can be treated and manufacturers such as Reynolds produce stainless tubing that largely negates this problem. There is not one material in the table that has advantageous properties in each category, which explains why manufacturers continue to fabricate frames from several different materials. Aluminium alloy is nowhere near as strong or stiff as steel, but has around one-third of the density. With titanium and steel we move towards more of a niche market. This is then placed inside a mould and cured at high temperature and pressure. First, there are three types of material properties: Physical – Density, color, electrical conductivity, magnetic permeability, and thermal expansion. Which Frame Material is Best? These are usually uni-directional - the fibres are all aligned in one direction - giving high strength along the axis of the fibres. Steel can also be shaped, though hydroforming for steel is not really applied to bicycle tubing. However, nowadays the ride of an aluminium frame can be exceptional. RTM arguably gives even better control over localised material properties, and can lead to overall higher quality carbon fibre parts. This may have been true with early frames but is not the case anymore. Advertising and commercial: sales@off-road.cc, Mountain bike, bikepacking and gravel bikes. Best mountain bikes you can buy for under £2,000, The best hardtail and full suspension mountain bikes you can buy for under £1500, Best MTB's that you can get shipped straight to your door, The best titanium gravel and adventure bikes you can buy, No, longer mountain bike geometry isn't a fad, First Look: Pipedream Full Moxie Frameset, MT Zoom Ultralight Inline Carbon Seatpost review, Maxxis Shorty 3C Maxx Terra EXO TR tyre review, The best gravel wheelsets you can buy in 2021. A tougher material is able to absorb more energy before failing, meaning it will bend rather than breaking in a brittle way. However, there is a limit to how thin tubing walls can be made before they become susceptible to damage, denting and more importantly buckling. The way this is done is know as the layup. Often carbon fibre with different properties will be used in different areas of the frame to tune compliance and stiffness as required. Thorough damage assessment on carbon frames is significantly more complicated. Chromoly (Chrome Molybdenum) Steel. Ovalised tubes essentially act as a larger tube in one direction, and as a smaller tube at 90 degrees to this. Elasticity: When an object responds to bending or stretching by returning to its original shape, it is said to have a high level of elasticity. One table will present material properties requirements for the selected materials commonly used for bicycle wheels, frame, components and helmet. Assembling thin walled tubing also becomes difficult to assemble, with heat from welding affecting heat-treatments and reducing strength in the weld area. It is completely different because it can be “designed” specifically for its application. However, the lower density will result in a frame weighing around 30% less than a steel frame. The individual tubes must then be bonded together. Look are one of the few manufacturers who use this method, and implement advanced techniques to form complex tube shapes and the complete frame. Contrary to what you might expect, outright strength is less important. 3Al-2.5V is the most widely used alloy, though the higher performing 6Al-4V also exists. Different steel alloys, such as niobium, mangaloy and of course stainless, are also used. Nonetheless, aluminium is a more brittle and weaker material than steel, and as such frames tend to be slightly overbuilt to make frames stronger and give a larger safety margin. Hydroforming is used with aluminium tubing to form complex shapes. There are two main aluminium alloys in use in the bike industry today – 6061 and 7005. Do you need the marginal gains that a lightweight carbon frame can provide, do you want the lightweight but cheaper compromise of aluminium, do you want the prestige and life-long durability of titanium, or do you want the traditional and versatile steel? The earliest bikes were simple wooden framed push along affairs but soon the material of choice was heavy iron, which in turn was superseded by steel. All metals used for bikes are an alloy. Aluminium road bikes – save for some custom designs – are fairly inexpensive. However, many, there is something romantic about a nicely made, high end steel frame. It is possible to make an excellent frame with any of the materials mentioned, but for a high performance frame, the choice will usually come down to  be either carbon fibre or aluminium. Frames are designed so that stresses are low enough that in normal loading it will not reach its fatigue life within its usage lifetime. It's worth noting that it's often how the chosen material is used by the engineers and manufacturers that matters most, and this is something that each brand will typically play with. That said, a crash that destroys a carbon frame is likely to destroy most other frames as well. However titanium genuinely provides a frame for life. Carbon fibre However the largest limitation of carbon fibre is that it is an inherently brittle material. Aluminium provides an excellent compromise, allowing lightweight bikes to be built at more reasonable costs. Control the geometries and dimensions of the tubing used to build the frame also has a very large influence on ride characteristics. It is incredibly strong, very stiff, easy to work with and cheap to manufacture. Each bicycle frame material offers a list of differing characteristics that will affect the cost, comfort, weight, stiffness, strength and durability. Some steels, such as 853 by Reynolds actually increase in strength after cooling due to the way they have been treated. This alloy contains 94.5% Ti, 3% Aluminium and 2.5% Vanadium, and is used because it combines the variety of benefits of Grade 5 with an ease of machining you don’t get in other similar grades. In metal frames a by-product of building the frame to the required strength is that the tubing will also resist “non-cycling” loads. Metals are isotropic, meaning their mechanical properties are the same in all directions. When a bicycle maker chooses a material to make a bike frame, he or she usually considers the following properties of the material. In 1897 Alfred M. Reynolds took out his patent on butted steel bicycle tubes and, for steel aficionados, a frame bearing the Reynolds stamp is a must have to the present day. Academia.edu no longer supports Internet Explorer. While as an element titanium is very abundant, it takes a lot of effort to refine and process into the tubing used for frames. What material properties are important in choosing bicycle frame material? The modulus of the epoxy resin is extremely low, resulting in a brittle material; which consequently affects the method of which the CFRP layers are applied. The core is commonly a removable inflatable bladder which applies internal pressure during the cure. There are some more exotic alloys, including scandium and lithium, in limited use, which aim to reduce frame weight even further. The excessive use of more material to reinforce frames resulted in stiff frames before designs became more refined. Reviews, buying advice and news. It's worth noting that it's often how the chosen material is used by the engineers and manufacturers that matters most, and this is something that each brand will typically play with. 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