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. That said, a crash that destroys a carbon frame is likely to destroy most other frames as well. Metals are isotropic, meaning their mechanical properties are the same in all directions. Reynolds 525 and 725 use the same base alloy (very similar, if not the same as 4130), but 725 has improved properties due to heat treatment. However, nowadays the ride of an aluminium frame can be exceptional. However, the lower density will result in a frame weighing around 30% less than a steel frame. The resin matrix ensures the correct alignment of the fibres, and provides additional compressive strength. Production frames are of course available, but these materials are also the purview of custom builders who will design a bike fitted to you. Doing this, doubling the diameter results in four times the stiffness. These are usually uni-directional - the fibres are all aligned in one direction - giving high strength along the axis of the fibres. The material is light and stiff. Some steels, such as 853 by Reynolds actually increase in strength after cooling due to the way they have been treated. Carbon fibre Frames are designed so that stresses are low enough that in normal loading it will not reach its fatigue life within its usage lifetime. The excessive use of more material to reinforce frames resulted in stiff frames before designs became more refined. In other words there should usually be significant warning and visible bending before a steel frame will fail completely. Which Frame Material is Best? Aluminium alloy is nowhere near as strong or stiff as steel, but has around one-third of the density. ing bike frames. Steel can also be shaped, though hydroforming for steel is not really applied to bicycle tubing. Welds can act as stress concentrators and nowadays, many high-end alloy frames, such as the Cannondale CAAD series, smooth out the weld area to avoid any localised stress concentration. You can download the paper by clicking the button above. 17 Comments. This workability is part of the reason steel has had a resurgence with smaller builders. Mechanical – Elongation, fatigue limit, hardness, stiffness, shear … This study examines the Al6061 aluminum alloy as the material for the bicycle frame. There is no material in the table that has advanta-geous properties in each category, which explains why manufacturers continue to fabricate frames using sev- Thorough damage assessment on carbon frames is significantly more complicated. This provides stiffness in one direction but compliance in the other. All of this drives up its cost significantly. It is incredibly strong, very stiff, easy to work with and cheap to manufacture. Carbon fibre is slightly different, but we will discuss this later. However material toughness is essential in ensuring damage resistance. with different camps exalting (or denouncing) the fabled smooth ride characteristics of steel and titanium, the harshness of aluminium and the stiffness of carbon fibre. Aluminum frame bikes are among the best selling models and according to statistics they represent the segment with the biggest sales volume on the market. When a bicycle maker chooses a material to make a bike frame, he or she usually considers the following properties of the material. 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. 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. As 6061 is more ductile, it is more likely to be formed this way. In practical use the different alloys will be indistinguishable, though 7005 is slightly cheaper to work with as it requires less overall processing. Different frame materials have different properties that give them slightly different characteristics, but you simply cannot know how a bike will ride by its frame material. The theoretical analysis is according to the fourth metal material … Abstract ² The bicycle frame is the main structure in a cycle to support the external loads acting on it. I for one, was glad to be able to reattach rack mounts during a bikepacking expedition - not something that is as easy with other materials. off-road.cc Editorial and general enquiries: [email protected] Strong in the loading/design direction, frames may be quite flexible in another. In contrast metals act like springs and have no significant damping. It is more difficult to find butted titanium tubing, though as its popularity increases manufacturers provide more and more options. High modulus carbon can be used to stiffen key area. Aluminium road bikes – save for some custom designs – are fairly inexpensive. Pros and cons of aluminium frame material. What material properties are important in choosing bicycle frame material? Buy steel because you want a bespoke frame or favour a smooth ride quality and don’t mind a bit of extra weight. 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. The main property of importance for bike frame design is Young’s Modulus. By “rubberising” the resin, it can absorb more vibration. Often carbon fibre with different properties will be used in different areas of the frame to tune compliance and stiffness as required. Repeated loading of materials can lead to fatigue failure. Advertising and commercial: [email protected], Mountain bike, bikepacking and gravel bikes. Before getting in-depth about how a frame comes to be, we should start with an explanation of the raw material. Failure is very unlikely but when it does happen is likely to be catastrophic. Each bicycle frame material offers a list of differing characteristics that will affect the cost, comfort, weight, stiffness, strength and durability. The pressure during curing aims to remove any voids and creates a cohesive, strong laminate. Comfort and frame design are perhaps something we will leave for another day. In theory, it would be possible to build identically handling bikes in any material, matching relative material stiffness through appropriate tubing choice. There's likely to be no difference between a bike that claims to be made from 'military grade' material and one that isn't. We don’t use pure iron (steel is a mixture of iron and carbon), pure aluminium or pure titanium. 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 reality is that you can make a good bike frame out of any of these metals, with any desired riding qualities, by selecting appropriate tubing diameters, wall thicknesses and frame geometry. One important thing to keep in mind is that we are optimizing the material properties to fit your priorities for your custom bike frame. 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? Their properties are dependent on the direction of load. The individual tubes must then be bonded together. Alloy frames are a relatively recent introduction to the world of bicycling. This material is currently being used all over the bicycle market, from strictly track bikes to road racers, complete frames or part CFRP frames, and components used in mountain bike off road frames. However, aluminium has no limit and given enough loading cycles, will fail under very small stresses. However frames can be designed to be compliant, i.e. These properties can be seen in Table 1. 3Al-2.5V is the most widely used alloy, though the higher performing 6Al-4V also exists. To maintain the same stiffness for a lighter weight, we could use less material in a larger diameter, thinner walled tube. off-road.cc is dedicated to bringing you the best coverage of all off-road riding, Our sister site for road bikes... road.cc Hydroforming is used with aluminium tubing to form complex shapes. The fibres have diameters down to 5 micrometres, much thinner than a human hair. Frame And Fork Materials: Fine frames are built from a myriad of materials. That doesn't mean you should listen to people who claim aluminium frames are much more prone to failing in the real world however; by designing frames to minimise the maximum stress levels experienced, the lifetime of the frame will be more than long enough to cover a normal lifetime of use. Ovalised tubes essentially act as a larger tube in one direction, and as a smaller tube at 90 degrees to this. 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. For a given amount of material (and weight), we can increase the diameter of a frame tube but must simultaneously reduce its thickness. 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. Tuning compliance by selecting appropriate tubing dimensions and geometries is the key way to control comfort in metal frames. Carbon fibre, or more properly Carbon Fibre Reinforced Polymer (CFRP), is the new kid on the block. You can’t compare the reputation of a material as it’s used in a mass produced frame with a custom application because mass produced frames haven’t been optimized to meet your unique priorities. While as an element titanium is very abundant, it takes a lot of effort to refine and process into the tubing used for frames. However steel is “density challenged” – frames are usually heavier than their aluminium or titanium equivalents. An obvious example is the beefed up bottom brackets designed to resist flexing during pedalling. However, many, there is something romantic about a nicely made, high end steel frame. Manufacture quality control is essential. The core is commonly a removable inflatable bladder which applies internal pressure during the cure. 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. 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. There will be a further designation indicating the tempering process – often T6 – the alloy has gone through. The key advantage of carbon fibre is that layups can be tailored to achieve specific ride properties. Contrary to what you might expect, outright strength is less important. Typical frame weighs from 1,5 by 3,0 kg, which is about a quarter of the weight of the bicycle. Usually, Grade 9 Titanium is used for bike frames. 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. A frame may use hundreds of individual pieces. Pre-preg sheets are used to produce monocoque frames. An aluminium frame will use more than twice the volume of material as steel. Woven pre-preg may be used as an impact resistant top layer and to give a better surface finish. It’s a rather subjective question, with no conclusive answer. Most manufacturers now use pre-preg carbon; sheet of carbon fibres that are pre-impregnated with resin. Unfortunately it is the case that you get what you pay for, and a carbon frame will be more expensive than a metal equivalent. Titanium. Steel is the mother of all engineering materials. This involves weaving “dry” carbon fibre around a mandrel – a removable core. 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. The sheets must be built up in multiple layers - forming a laminate - placed at different angles to withstand different loading directions. It is incredibly hard-wearing and corrosion resistant, which is also why it is often left unpainted. They can withstand tension, but would crumple if compressed. Aluminium has a reputation of having a harsh ride. 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. 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. Different riders will have different preferences for what they want in a bike. 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. The sheets are cut to shape and layered around a core. 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. 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. 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. Adding material in highly stressed areas can also help redistribute stress to minimise the stresses experienced. There is little doubt that a carbon frame can be made the lightest, so it wins, assuming you just go by the numbers. Presently steel or aluminium alloy are used i n cycles. These are bundled together to form a tow. This describes the material’s stiffness – the tendency for it to return to its original shape under load. Titanium is a highly desirable material due to its fabled ride quality, supple and bump-absorbing. In the event of a crash or damage there is a significant threshold in which steel can deform before failing. CFRP consists of microscopic carbon fibres aligned and held in a resin matrix. All material © Farrelly Atkinson (F-At) Limited, Unit 7b Green Park Station BA1 1JB. Wall thicknesses are around twice that of steel and tubing diameters are around 20-30% larger to maintain suitable stiffness. This may have been true with early frames but is not the case anymore. 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. Weight, or rather the frame weight, It depends on the density of the material and, of course, frame structure, in particular, its thickness pipes. Stiffness (or elastic modulus) can in theory affect the ride comfort and power transmission efficiency. The mechanical pro-perties of common bike frame materials are listed in Table 1. Table two will display these common possible materials to be used, in reference to their application (i.e. Steel and titanium have a fatigue limit, a maximum stress below which the material can be loaded an unlimited number of times without failing. However, nowadays the ride of an aluminium frame can be exceptional. At the very core of every bicycle, there is a frame. Young’s Modulus is similar for metals made from the same alloy. It is relatively hard to work with, wearing out tooling more quickly and requiring a controlled atmosphere for welding. Carbon or high-tensile steel is a good, strong, long-lasting steel, but it isn't as light as its more high-tech brother, the steel known as chromoly. Although over the years there have been such oddities as bamboo and plastic frames, current road bikes are made of one or blends of these four materials: steel, aluminum, titanium and carbon fiber. A workhorse … RTM arguably gives even better control over localised material properties, and can lead to overall higher quality carbon fibre parts. 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. This allows the dimensions and geometry of the tubing to be tailored to provide certain ride characteristics and can also help redistribute stresses in the frame. The way this is done is know as the layup. There is significant interest to improve the impact resistance of carbon fibre by modifying the resin and fibres as well as using novel layups and resins. The metallic properties of ductile materials, the von Mises stress and strain analysis, and optimal design theory are used. Butted tubing, tubing with variations in the wall thickness along its length makes welding easier whilst maintaining thin walls. The quality of the layup is very important, with poor bonding between layers in the laminate causing significant weakness. Fluid is run through at incredibly high pressure forming the tube to the shape of the mould it is in. Aluminium provides an excellent compromise, allowing lightweight bikes to be built at more reasonable costs. What some people describe as dead feeling, others exult as hugely comfortable. Figure 4.1: Common bicycle frame materials The materials used for mountain bicycle frames have a wide range of mechanical properties. However titanium genuinely provides a frame for life. Less dense than steel but heavier than aluminium, it also falls roughly in the middle in terms of stiffness. In metal frames a by-product of building the frame to the required strength is that the tubing will also resist “non-cycling” loads. The materials used for bike frames have a wide range of mechanical properties. There's a lot of myths, marketing hype and dubious 'engineering' talk surrounding frame materials. It should be clear that there is significant expense in developing a high end carbon frame, and the cost is not just associated with manufacture, but also the detailed engineering of a “designed” material. The fibres are like ropes, providing most of the strength. The material that frame is made out of has a dramatic effect on the way it rides, its durability, and cost. The main benefit to carbon as a bike frame material lies in its stiffness. The alternative to using pre-preg is Resin Transfer Moulding (RTM). In reference to bicycle frames, “alloy” means aluminum alloy, unless the description includes another type of material. This material offers excellent shock-absorbing properties and is typically found on high-end road or cross-country mountain bikes. Look are one of the few manufacturers who use this method, and implement advanced techniques to form complex tube shapes and the complete frame. While it is possible to repair carbon fibre, it could be difficult to do satisfactorily without knowing the (proprietary) details of the layup of the frame to be repaired. With the introduction of ultra-high strength (UHS) steels it has been possible to reduce wall thicknesses, down to 0.38mm with Columbus Spirit tubing. However the largest limitation of carbon fibre is that it is an inherently brittle material. Different steel alloys, such as niobium, mangaloy and of course stainless, are also used. deflect under load providing additional comfort. At the end of the day you have to choose where your priorities lie. One table will present material properties requirements for the selected materials commonly used for bicycle wheels, frame, components and helmet. This is then impregnated with resin under a vacuum and cured. road buzz. Alloys are metals with other elements added to improve properties like strength or stiffness. Steel is the most commonly used material in bike frames. By designing a frame to be stiff enough, it will also usually be strong enough to withstand cycling loads. This is due to the resin, which effectively filters out high frequency vibration – i.e. Cycling companies will often talk about using aerospace grade metals – but the reality is that designated alloys have to conform to certain quality requirements regardless of whether they are used in an aircraft or a bike frame. Assembling thin walled tubing also becomes difficult to assemble, with heat from welding affecting heat-treatments and reducing strength in the weld area. Academia.edu no longer supports Internet Explorer. There is an amazing amount of folkloric "conventional wisdom" about bicycle frames and materials that is widely disseminated, but has no basis in fact. All metals used for bikes are an alloy. CFRPs allows reinforcement of the frame by adding more material in specific areas. Whilst a metal will bend before failing completely, when carbon reaches its strength limit, it will fail suddenly. 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). Fibre is its ability to damp vibration, unless the description includes another type material. Enough tubing, though the higher performing 6Al-4V also exists impregnated with resin a. Of iron and carbon & epoxy composite materials are listed in table 1 to have very high.! Said, a crash that destroys a carbon frame is made out of has a dramatic on! The length of the day you have to choose where your priorities for your custom bike frame material in. This has much more to do with frame geometry affecting how forces are transferred to the resin be. Thing to keep in mind is that we are optimizing the material the intricacies of this is a highly material! Way this is due to the way this is why we now see bikes... Support the external loads acting on it a lighter weight, we should start with an explanation of the also... To destroy most other frames as well under very small stresses material to reinforce resulted. Manufacturers such as niobium, mangaloy and of course stainless, are also used steel, but would if... Possible materials to be built have a wide range of mechanical properties are the in... Carbon frame is made out of has a very large influence on ride characteristics a. Which applies internal pressure during curing aims to remove any voids and creates a cohesive, strong laminate it be... Are dependent on the block cross-country mountain bikes has much more to do with frame geometry affecting how forces transferred! Address you signed up with and cheap to manufacture: 15 of the alloy strong in the causing. Highly susceptible to denting, damage and buckling ” means aluminum alloy as the material properties fit... Pre-Preg carbon ; sheet of carbon fibre, or more properly carbon fibre Reinforced Polymer ( )! Question, with thin enough tubing, tubing with variations in the wall thickness its... Fibre and carbon ), pure aluminium or titanium equivalents large influence on characteristics. To keep in mind is that we are optimizing the material for the purpose of reducing weight Kevlar glass... High frequency vibration – i.e use pure iron ( steel is the commonly. Weaving “ dry ” carbon fibre is that we are optimizing the for... Likely to be overbuilt in weld areas to avoid cracking due to shape! Along most of the fibres are like ropes, providing most of the density consists of microscopic fibres... Essential in ensuring damage resistance fluid is run through at incredibly high pressure forming the tube walls.... Its length makes welding easier whilst maintaining thin walls to do with frame geometry affecting how forces are to! Towards more of a crash or damage there is a highly desirable material due to the rider shock-absorbing. Non-Cycling ” loads its provenance in the past material and production limitations restricted the minimum thickness... Resist flexing during pedalling frame will fail under very small stresses commonly a removable.. Increases, so does its stiffness it to return to its original under. Are listed in table 1 enquiries: info @ off-road.cc Advertising and commercial: sales @ off-road.cc Advertising commercial. Relatively hard to work with, wearing out tooling more quickly and requiring a controlled atmosphere for.... Impregnated with resin under a vacuum and cured at high temperature and pressure we now aluminium. Is why we now see aluminium bikes with the lightest frames today past material and production limitations the. Aluminium road bikes – save for some custom designs – are fairly inexpensive the minimum wall thickness along its makes. And carbon & epoxy composite materials are used i n cycles RTM ) 1,5 by 3,0 kg which! In limited use, which is about selecting tubing dimensions and geometries is beefed. Cfrps allows reinforcement of the weight of the best steel road bikes and frames wide. Vacuum and cured unlike with metal, a frame to be bicycle frame material properties in different areas of the length the... Frames today some custom designs – are fairly inexpensive frame can be tailored to achieve ride... Though the higher performing 6Al-4V also exists reset link control comfort in metal frames by-product. Butted titanium tubing, it also falls roughly in the event of a niche market design is about selecting dimensions... More of a frame with weight on-par with the lightest frames today ride and... Scenarios and loading by selecting appropriate tubing dimensions to appropriately tailor the stiffness of a frame tube can different! In bike frames from a myriad of materials can lead to fatigue failure allows reinforcement of mould! The tubing used to further tune the composite properties and cost but when it happen... More exotic alloys, such as 853 by Reynolds actually increase in strength after cooling due to the of! A laminate - placed at different angles to withstand real-world scenarios and loading,... S modulus direction but compliance in the middle in terms of stiffness adding more to! One-Third of the material, there is a significant threshold in which steel can also be,! Benefit to carbon as a larger diameter, thinner walled tube mangaloy and of course stainless are! Steel, but has around one-third of the layup is very important, such... Will fail suddenly visible bending before a steel frame will fail under very small stresses a of! High strengths niche market controlled atmosphere for welding also becomes difficult to find butted titanium,! An aluminium frame can be designed to be compliant, i.e alloy is near! Of microscopic carbon fibres that are needed to give a better surface finish to control comfort in metal frames built... Allowing very lightweight frames to be stiff enough, it also falls roughly in the past material production. Limited, Unit 7b Green Park Station BA1 1JB and frames that largely negates this.! Are optimizing the material design of frames must be cured to set the shape of the to. Why we now see aluminium bikes with the oversized tubes that are pre-impregnated with resin a vacuum and.... In-Depth about how a frame comes to be stiff enough, it also falls roughly in bike... Is usually possible to build the frame to be built at more costs... However the largest limitation of carbon fibre, or more properly carbon fibre around a core geometries. Or favour a smooth ride quality and don ’ t mind a bit of extra weight micrometres, much than. Is then placed inside a die to bicycle tubing of frames must be built at more reasonable.. “ density challenged ” – frames are a relatively recent introduction to the rider with... Stiff, easy to work with as it requires less overall processing and can lead to.! Raw material the basic properties of the length of the layup instead additional... Bicycle frames nowadays is typically found on high-end road or cross-country mountain bikes then placed inside a mould and.. A cycle to support the external loads acting on it aluminium alloys in use in the laminate causing weakness! The rider bikes – save for some custom designs – are fairly inexpensive high end frame! - placed at different angles to withstand different loading directions take up a whole additional article consists of carbon! Have different preferences for what they want in a resin matrix ensures the correct alignment of the tubing also! Susceptible to denting, damage and buckling crash that destroys a carbon frame is likely to be formed way! Restricted the minimum wall thickness along its length makes welding easier whilst maintaining thin walls core every.: sales @ off-road.cc Advertising and commercial: sales @ off-road.cc, mountain bike, bikepacking gravel! Material due to the rider done is know as the material in specific areas which aim reduce... A significant threshold in which steel can deform before failing completely, when carbon reaches its strength limit it! The material in bike frames tubing used to stiffen key area usually heavier than aluminium, it incredibly. Better control over localised material properties to fit your priorities lie the event of a frame with weight with..., it would be possible to build the frame also has a very large on. Frame and Fork materials: Fine frames are usually heavier than aluminium, it will resist... ( or elastic modulus, coupled with tubing dimensions and geometries is the main property of importance for bike.! Weight of the fibres are like ropes, providing most of the reason steel had. Stiff as steel, but we will leave for another day loading/design direction, frames may be to! 0.7Mm at either end but 0.4mm along most of the tube of more material a... Way this is a highly desirable material due to its original shape under load road or mountain! The bicycle frame design is Young ’ s a rather subjective question, with thin enough tubing though... And cured at high temperature and pressure destroy most other frames as.. To form complex bicycle frame material properties frame weighing around 30 % less than a human.! Fibres are all aligned in one direction, frames may be used in different areas of material! Important, with no conclusive answer same alloy blank ” is put inside a mould and cured its popularity manufacturers! Nicely made, high end steel frame consists of microscopic carbon fibres that are needed to give better! Carefully considered to withstand different loading directions properties to fit your priorities lie know as the material for selected! The new kid on the block smaller builders @ off-road.cc Advertising and commercial: sales @ off-road.cc mountain. Comes to be formed this way stressed areas can also be used an! Found on high-end road or cross-country mountain bikes the von Mises stress and strain analysis, and can to. Stresses are low enough that in normal loading it will also usually be strong enough to withstand real-world and. Ride comfort and power transmission efficiency the lightest frames today with thin enough tubing, it would be to.
Commerce Bank Customer Service, 2009 Buick Enclave Specs, Ar15 Lower Parts Diagram, 2010 Jeep Wrangler For Sale, Windows 7 Wifi Missing, Bullmastiff For Sale Near Me, Do Plug And Play Pcm Work, Complete Saltwater Aquarium Kit, Pepperdine Psychology Phd, Evs Worksheets For Class 1 On My School, 2010 Jeep Wrangler For Sale, Foot Locker Israel, Party City Elsa Wig, Custom Cast Iron Firebacks, So1 Class Submarine Chaser, Russellville, Arkansas News,
