Bicycle frame design calculations

What are the engineering calculations done while designing a. A bicycle frame has been analysed as a threedimensional framework and stresses and deflections predicted using a finite element computer program. A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. These tools definitely help to drastically reduce the design time. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles. Aluminums main advantage has always been lightweight. Other important components are the tires, wheels, and pedals. Bikecad can be used to design any diamond frame bike and control it through a comprehensive set of parametric input fields. Low racer recumbent bike frame eric conner 6 short wheelbase frame figure 5 is the design of the most common of all the short wheelbase swb recumbent bikes are amongst the most desired of them all. It also differentiates it from this competing concept, which basically makes the seat into the bicycle version of. The bicycle design centre were featured on rte 1s new show big life fix on wednesday night march 18th at 9.

Bicycle frame size calculator measure bike size guide. You can also control settings such as units, display settings of framing members and. In this article on mechanical design tutorial today i will talk about design of a simple l. Bicycle design use the illustration of a bicycle below to answer question 23. The overall system the modules the components in order to train your mind to synthesize structures, start by observing the world around you. Benchmarking was performed at the early stage of the design process to research on typical dimension of the frames as well as material used. The safety factor you will use in the design of the bicycle frame. Bicycle frame design using solidworks simulation part 1. I am thinking of going with the motobecane frame that states its 49, but for a. The design calculations and analysis procedures are represented in the following presentations. Frame version 1 was primarily used on industrial risks. For a bike to pass this test the frame may deform by up to 40mm following an impact with a known mass. Material and design optimization for an aluminum bike frame. The bicycle that has been selected for this project has the specifications as listed in table 1.

A finite beam element computer program is used to calculate frame stresses. Ecaeed az61al2o3 mmcs, the calculation results show that not only is the. Loads, stresses, and deflections in bicycle frames article pdf available in the journal of strain analysis for engineering design 214. It is very important that the bike fits your body in order to optimise comfort and performance. In practice it takes a time for the system pressure to rise and the friction to build up. Key wordspedal arm, bicycle frame, boundary condition, analytical analysis. That said, just because the ett is the same between the two bikes, it doesnt mean the bikes will have the same reach. Although wheelbase is dependent on more than just the frame size it is also a function of fork geometry, lower headset stack, and if the front and rear wheels are different sizes, then wheel diameter as well the wheelbase dimension is found in the frame tab of the dimensions dialog box. The design calculations and analysis procedures are represented in the. When any material is subjected to repeated cyclic loads, its design strength must be decreased in certain prescribed ways, for steels, the design strength decreases until, at about one million stressreversal cycles, a fatigue endurance limit is reached. You will get a printable page with your recommended frame size.

Static and dynamic mechanical analysis was done on the design to test its rigidity and strength. Engineering inspiration brake system design calculations. The frame consists of a top tube, down tube, head tube, seat tube, seat stays, and chain stays. The team collaborated with a local bike company, in the process of developing a new 6061t6 aluminum mountain bike, to investigate the fatigue behavior of the new frame and optimize the materialheat treatment and frame design. Material properties and design aspects of folding bicycle frame. Bmx bikes are designed for racing, jumping and freestyle riding on dirt tracks, ramps and in skate parks. When it comes to buying a bicycle and especially a classic road bike it is very important to make sure that you choose a bicycle in the right size.

The specifications for the bicycle used in the project 1 item specification best use mountain biking frame 6061 aluminum fork sr suntour xct, 75mm travel. The problem to be modeled in this example is a simple bicycle frame shown in the following figure. The frame is supported only by the bottom bracket shell, leaving all other points on the frame including head tube and rear dropouts free to move. The maximum allowable deflection at the handle bars under heavy peddling by an 80 kg rider. Brake design and safety 2nd edition by ruldolf limpert. Describe where these simple machines are found on a bicycle. Sep 26, 2014 the trade off for that capability though is performance the bikes frame will be heavier and less capable of absorbing impacts than a traditional frame design. The tables give the summaries of the input data and calculation results as found in the report generated by the software. Wheelbase is the horizontal distance from the rear axle to the front axle. Fatigue analysis of a bicycle fork a major qualifying project submitted to the faculty. The oxypropane handbrazed framesets feature handcut lug work, investment cast wishbone seatstays and patented seatpost binder.

Choose the type of bike youre interested in and then enter your measurements. Hinaultgenzling custom track and road bicycle frame sizing. We assume that the frame is made out of aluminum tubes which will be modeled as 1d elements i. The effective top tube ett length is the simplest way to determine a bikes size. Bikecad lets you design your dream bicycle online, for free. If youve ever wondered how to build a bicycle this is the place. Paolo explained, its proven to be a great use of materials, great for. The problem to be solved in this example is the analysis of a bicycle frame. Jan 09, 20 triaxial tension in a lugged steel bicycle frame. The bicycle frame is the main load bearing structure of the bicycle and in order to select materials for its construction or to make an efficient frame design the. Bicycle maintenance, bicycle design, bicycle manufacturing. Note that none of these estimated values are automatically factored into the frame design. When any material is subjected to repeated cyclic loads, its design strength must be decreased in certain prescribed ways, for steels, the design strength decreases until, at about one million stressreversal cycles, a. Paolo explained, its proven to be a great use of materials, great for bracing angles, great for strength.

Dec, 2014 video 03 in the beginner build bicycle frame series. Bikecad was originally intended to allow custom frame builders to quickly design a bike and easily obtain the lengths and angles. The bicycle frame is a standard component of a bicycle, and every bicycle factory has a different design. Our bike size calculator will help you to determine the correct frame size. Pdf a bicycle frame has been analysed as a threedimensional framework and stresses and. It also differentiates it from this competing concept, which basically makes the seat into the bicycle version of the club steering wheel lock. The flexibility means that any weight or stiffness is achievable within the range of physical property limits of the carbon itself. In addition, the increased demand for lighter bicycle components while maintaining a high level of safety requires an integrated mechanicalmetallurgical analysis and validation of a given design and materialsprocess optimization.

They can also be a little harder to handle with heavy front panniers at higher speeds too. Mechanical design tutorials on basic calculations bright. Best online bike fit calculator how to choose the right bicycle frame size. Conceptual design of a bicycle frame based on a report partly written by lena hartung, nicolas torgau, thomas lehmann, kristian holm and matthias goelke students at altair updated to hw 2017. Irelands only bicycle frame manufacturing company were given a unique task by a brand new rte series, big life fix, that challenges a group of leading designers. The geometry of the frame governs the properties and performance of the bicycle.

Road bikes and mountainbikes is a loose term, mostly due to the mountainbike pa. If i first touch the how can geometries be different part, simple, different needs demand different geometries. Starting with the geometry, i will move on to the tube shapes and componentry to come up with an engineered speed machine. Watch a beginner build a tig welded steel bicycle frame. Pdf design of aluminum bicycle frames researchgate. Pdf loads, stresses, and deflections in bicycle frames. The long wheelbase and long fork rake will provide additional stability and comfort while riding the higher trail of the front end will help your bike to handle well with a load.

The design and manufacture of bicycle frames has largely been an art, performed by. The frame was damaged, as seen below, when the rider of the bicycle crashed directly into a cement post. Here, youll find tutorials on using bikecad pro, a standalone application for bicycle frame builders and bicycle fit specialists that runs on a pc, a mac or on linux. Elementary aspects of road bicycle design, engineering and. This is a different world for me, but per the calculations in your article above my frame size should be a 49. The trade off for that capability though is performance the bikes frame will be heavier and less capable of absorbing impacts than a traditional frame design. The head tube of the frame holds the steer tube of the fork, which in turn holds the front wheel.

To measure front triangle deflection, i slipped a solid steel bar one inch in diameter through the head tube to simulate a front fork. An existing frame of hero cycle as a reference for design. How comfortable your bike is, the ease and grace with which it tackles the road, how long it lasts, and how easy it is to maintain, are all functions of your bikes design the calculations that go into each angle, the placement of each part, the alignment of each element with each other. This holds the frame in a position horizontal to the ground. An important safety concern in bicycle frame design is fatigue failure. The rinard frame deflection test sheldon brownbicycle. Hinaultgenzling custom track and road bicycle frame. This design has changed very little since the advent of the saftey bicycle in the 1880s.

Bicycle frame geometry is particularly important if youre planning on using front and rear loads as. This is especially true with regards to bicycle stability, which is the result of a complex dynamic interaction within. This paper talks about selection of material for bicycle frame and their comparison. An annotated version of the position plot showing these and other descriptive dimensions is shown in figure 2, with those pertaining to the contact points shown in red. All the designs, calculations, drawings, analysis of the strtuctural. Objectives the purpose of this report is to obtain the maximum stresses in the twodamaged frame members using hand calculations.

Pictures of the frame that were taken after the crash 2. You will specify the maximum deflection in your design specifications. Video 03 in the beginner build bicycle frame series. A company designed a new road bike and wished to perform an impact strength test on the bicycle frame, as outlined in the astm f271108 2012 standard. Abstractthe bicycle frame is the main structure in a cycle to support the external. The custom frame philosophy is at the heart of the sponsor and truly sets them apart from other. This article analyzes the stress and optimizes the design of a customized bicycle frame using proengineer digital solid modeling and design software, through highresolution numerical computeraided engineering cae simulations of bicycle frame, stress analysis, numerical analysis, and optimal designs of the frame structure. The frame is to be built of hollow aluminum tubing having an outside diameter of 25mm and a wall thickness of 2mm. The deceleration used in calculations is a steady state one called mfdd mean fully developed deceleration. Road bikes, designed for paved surfaces, are ideal for road riding, racing, touring and commuting. The free version allows you to input frames with a maximum of 3 members with applied point loads and moments for 2d frame analysis.

On a bike with road handlebars using a sub10kg 22lbs front load, i tend to really like this design approach. Structural analysis of bicycle structure and improvement. Our bicycle size calculator will tell you what size bike you need. The bicycle frame the bicycle frame is the main load bearing structure of the bicycle and in order to select materials for its construction or to make an efficient frame design the loads carried by the various components must be evaluated under realistic conditions. In an earlier blog, i described the difference between a lugged frame and a tig welded frame.

Theoretical results for simple loading case were compared with strain gauge measurements in laboratory tests. Mountain bikes are designed for offroad riding on rough terrain such as dirt, mud, gravel, roots and rocks. This design has been the industry standard for bicycle frame design for over one hundred years. What are the engineering calculations done while designing. Although the number of components of a bicycle is small, the interaction between them and the dynamic principles involved, is complicated. Frames are required to be strong, stiff and light, which they do by combining different. As pictured in figure 5, the bikes name comes from the total system having a smaller wheel in front then in the rear. Nowadays lots of software tools are available in market to take care about the lengthy calculations.

However, ive found that low trail bikes ride a bit strange without any front load. The firm is also the usa manufacturers representative for marchetti spa, bergano italy integrated bicycle systems. The project is applicable for any bicycle available in the market. A mountain bicycle frame was to be designed for an adult male. Bike frame construction in this section we are going to construct a bicycle frame as shown below in hypermesh. Conceptual design of a bicycle frame altair university. This free online frame calculator will generate and find the bending moment and shear force diagrams of a 2d frame structure. Bicycle physics is a broad and complex subject, perhaps more so than one can imagine. The new method relies on measurements of rider induced loading to perform a stress analysis of a bicycle frame. The most popular frame design is known as the diamond or double triangle. Most of the cases a mechanical design engineer only needs to put input and the software tools give the output in desired format. Seat tube length isnt too important for most people with the exception of those who need additional standover. A bicycle is a composite of several simple machines.