Hubbry Logo
Motorcycle frameMotorcycle frameMain
Open search
Motorcycle frame
Community hub
Motorcycle frame
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Motorcycle frame
Motorcycle frame
Motorcycle frame
View on Wikipedia
from Wikipedia

Triton: A Triumph engine in a tubular steel Norton Featherbed frame

A motorcycle frame is a motorcycle's core structure. Its main function is to provide a torsionally rigid connection between the steering head at the front and the swinging-arm bearing at the rear for predictable handling and safety. It also supports the engine, the rider and any passenger or luggage. Also attached to the frame are the fuel tank and battery. At the front of the frame is found the steering head tube that holds the pivoting front fork, while at the rear there is a pivot point for the swingarm suspension motion. Some motorcycles[1] include the engine as a load-bearing stressed member; while some other bikes do not use a single frame, but instead have a front and a rear subframe attached to the engine.[2]

Materials

[edit]

In the early days, motorcycles were little more than motorised bicycles, and consequently frames were tubular steel. While the use of steel tubing is still common, in modern times other materials, such as titanium, aluminium, magnesium, and carbon-fibre, along with composites of these materials, are now used. As different motorcycles have varying design parameters (such as cost, complexity, weight distribution, stiffness, power output and speed), there is no single ideal frame design, and designers must make an informed decision of the optimum choice.[3]

Steel

[edit]

In Europe and the USA, steel tubing was the default material until recent times. All the major manufacturers (AJS, Ariel, BSA, Matchless, Norton, Sunbeam, Triumph, Velocette, BMW, DKW, Ducati, Moto-Guzzi, Harley-Davidson and Indian) used steel tubing.

Examples

Aluminium

[edit]

Unlike the development seen in bicycle frames where tubular steel frames were succeeded by frames welded out of round or ovalized aluminium tubing, the aluminium in motorcycle frames is almost exclusively welded in more angular forms, and often forming a monocoque frame.

Examples

Carbon fibre

[edit]
Ducati Panigale V4 Superleggera with Carbon Fibre Frame

In 1983, Armstrong motorcycles produced a 250cc Grand Prix motorcycle using a revolutionary carbon fiber frame.[4] Following the technology being used by the Formula One industry, Armstrong designers Mike Eatough and Barry Hart created the first motorcycle using a carbon fiber frame to compete in Grand Prix racing.[4] In 2020 Ducati introduced the Panigale V4 Superleggera featuring a carbon frame, carbon wheels and swingarm.[5]

Examples

Magnesium

[edit]
Magnesium framed Elf 5
Examples

Titanium

[edit]
Examples

Composite

[edit]
Greeves 250DCX Sportsman 1962
Examples
  • Bimota SB8K, composed of two aluminium alloy beams and carbon fibre plates
  • MV Agusta F4 750 Serie Oro, magnesium and aluminium
  • Greeves 250DCX Sportsman, with cast alloy "downtube", tubular steel rear subframe and semi-monocoque spine.

Types

[edit]

Spine or backbone

[edit]

The motorcycle engine is suspended from a single spine. Spine could be a solid structure.

Examples

Single cradle

[edit]

The motorcycle engine is held in a single cradle with a single spine.

Examples

Half-duplex cradle or double cradle

[edit]

The motorcycle engine is held in a double cradle with a single spine and single downtube.

Examples
Double cradle frame on Honda CB750

Full duplex cradle

[edit]

The motorcycle engine is held in place within a pair of separate cradles. The Norton Featherbed frame was the classic example, but many "duplex" frames actually have a single spine beneath the tank.

Examples
Twin-beam frame on Kawasaki ZX-10R
Aluminum beam frame on Buell Lightning

Perimeter

[edit]

Also called beam or twin spar, two beams wrap around the engine to join the steering head and swing arm in the shortest distance possible for better rigidity. Beams are usually made of pressed metal (steel/aluminium). The trellis frame employs the same concept but uses welded members to form a trellis instead of pressed metal.

Antonio Cobas is credited with pioneering the modern, aluminum perimeter frame chassis now used on many modern racing and production motorcycles.[8] In 1982, Cobas developed a stronger and lighter aluminum twin-beam chassis to replace the steel backbone frames.[8] The technology was copied by major motorcycle manufacturers and by the 1990s, all the major racing teams in Grand Prix competition used the aluminum frame design pioneered by Cobas.[9]

Examples

Pressed

[edit]
Pressed steel frame on Ariel Arrow

The frame is pressed or stamped from sheet metal to form a car-type semi-monocoque. One of the earliest examples was the 965cc motorcycle produced by Louis Janoir in 1920, which used pressed steel for the frame, rear swinging arm, and the front forks. The frame may be entirely pressed (Ariel Arrow), or may have just a pressed aft section connected to the steering head by a conventional steel tubular spine (Honda Super Cub). Both the Super Cub and the Arrow also have pressed steel forks, instead of conventional telescopic forks.

Examples

Monocoque

[edit]
Main article: Monocoque

More common in the car world, a monocoque frame comprises a structure where loads are supported through its external skin. On motorcycles they are used almost exclusively on racing motorcycles.

French industrialist and engineer Georges Roy attempted in the 1920s to improve on the bicycle-inspired motorcycle frames of the day, which lacked rigidity. This limited their handling and therefore performance. He applied for a patent in 1926, and at the 1929 Paris Automotive Show unveiled his new motorcycle, the Art-Deco styled 1930 Majestic. Its new type of monocoque body solved the problems he had addressed, and along with better rigidity it did double-duty, as frame and bodywork provided some protection from the elements. Strictly considered, it was more of a semi-monocoque, as it used a box-section, pressed-steel frame with twin side rails riveted together via crossmembers, along with floor pans and rear and front bulkheads.[13]

1968 Ossa 250 cc Grand Prix racer

A Piatti light scooter was produced in the 1950s using a monocoque hollow shell of sheet-steel pressings welded together, into which the engine and transmission were installed from underneath. The machine could be tipped onto its side, resting on the bolt-on footboards for mechanical access.[14]

A monocoque-framed motorcycle was developed by Spanish manufacturer Ossa for the 1967 Grand Prix motorcycle racing season.[15] Although the single-cylinder Ossa had 20 horsepower (15 kW) less than its rivals, it was 45 pounds (20 kg) lighter and its monocoque frame was much stiffer than conventional motorcycle frames, giving it superior agility on the racetrack.[15] Ossa won four Grands Prix races with the monocoque bike before their rider died after a crash during the 250 cc event at the 1970 Isle of Man TT, causing the Ossa factory to withdraw from Grand Prix competition.[15]

Notable designers such as Eric Offenstadt and Dan Hanebrink created unique monocoque designs for racing in the early 1970s.[16] The F750 event at the 1973 Isle of Man TT races was won by Peter Williams on the monocoque-framed John Player Special that he helped to design based on Norton Commando.[17][18] Honda also experimented with the NR500, a monocoque Grand Prix racing motorcycle in 1979.[19] The bike had other innovative features, including an engine with oval shaped cylinders, and eventually succumbed to the problems associated with attempting to develop too many new technologies at once. In 1987 John Britten developed the Aero-D One, featuring a composite monocoque chassis that weighed only 12 kg (26 lb).[20]

An aluminium monocoque frame was used for the first time on a mass-produced motorcycle from 2000 on Kawasaki's ZX-12R,[21] their flagship production sportbike aimed at being the fastest production motorcycle. It was described by Cycle World in 2000 as a "monocoque backbone...a single large diameter beam" and "Fabricated from a combination of castings and sheet-metal stampings".[22]

Single-piece carbon fiber bicycle frames are sometimes described as monocoques; however as most use components to form a frame structure (even if molded in a single piece),[23] these are frames not monocoques, and the pedal-cycle industry continues to refer to them as framesets.

2006 ZX-14 cutaway showing its aluminium monocoque frame
Examples

Semi-monocoque

[edit]
Main article: Monocoque

If a "monocoque" frame uses additional support, such as tubes or longerons, the frame is more properly called a "semi-monocoque". An example is Peter Williams' semi-monocoque Norton racer.

JPS Norton with semi-monocoque frame

Trellis

[edit]
Steel trellis frame (red) on a Ducati Monster 1000. The engine is a stressed member.

A trellis frame connects the steering head to the swingarm pivot as directly as possible using metal tube arranged in triangulated reinforcement. Using lattice girder principles, a trellis frame is typically constructed of round or oval section metal tubular segments that are welded or brazed together. A well-designed trellis frame should provide a strong, lightweight structure that simplifies placement of engine and components, and gives good access for maintenance. Although construction of a trellis frame needs a more complicated process than, say, an alloy beam frame, it requires only a simple jig and a competent welder. No heavy capital outlay is required, so a trellis frame is ideal for a model that may be made in relatively small numbers. For this reason, the trellis frame has found favour with European manufacturers, and Ducati in particular.

Some motorcycles, such as the Yamaha TRX850, have hybrid frames that employ alloy castings at the swingarm pivot area. Another variation is to suspend the engine from a trellis frame, but have the swingarm pivot cast into the rear of the engine.

Examples

Engine as a stressed member

[edit]
Further information: Stressed member engine
Harley-Davidson Model W with structural tubes bolted directly to engine case to complete the frame triangle

For rider comfort, a motorcycle's engine can be mounted on rubber bushings to isolate vibration from the rest of the machine. This strategy means the engine contributes little to frame stiffness, and absorbing rather than dissipating vibration can lead to stress damage to the frame, exhaust pipes, and other parts.[3]

Instead, if the engine is rigidly mounted to the frame, vibrations pass to and are dissipated via the whole frame, and the rider. Rigid mounting allows the engine to contribute to the overall stiffness of the frame. It also becomes possible to mount the swingarm directly to the engine rather than the frame, avoiding the need for frame members extending downward to the swingarm pivot. By increasing the number of mounting points between the engine and frame, vibrations and stress can be better dissipated in the frame, typically creating a triangle between the swingarm in the rear, the cylinder head at the top and the lower crankcase area at the front. If a rigidly mounted engine not only contributes to, but is critical to, the stiffness of the frame, and is an integral part of closing the triangle or trellis structure that transfers force from the headstock to the swingarm, to the point that without the engine the frame would be deformed, the engine is called a stressed member, or a lifted engine. Sharing the load between the engine and frame reduces the overall weight of the motorcycle.[3]

Stressed member engines were pioneered at least as early as the 1916 Harley-Davidson 8-valve racer, and incorporated in the production Harley-Davidson Model W by 1919.[24] This was called a keystone, or diamond, frame.[25][26] The 1946 Vincent Series B Rapide was designed with an advanced chassis, termed a "tour de force for its day,"[27] that included a stressed member engine. During early testing of the 1983 Kawasaki GPZ900R, twin downtubes were included, creating a full cradle, but the downtubes were found to carry little load, so they were removed, relying entirely on the combination of the steel backbone and engine for chassis rigidity.[28] BMW's R1100 series twins of 1994 relieved the frame of stress entirely, with the engine carrying the total load from the front Telelever fork to the rear Monolever.[29][30]

Stiffness

[edit]

Frame stiffness is a problem for motorcycle designers, as it was for the bicycle frames that motorcycles are descendants of.[31][32]

Modifying the stiffness of a factory-produced frame can be undertaken to improve handling characteristics. This is often done by triangulating the factory frame.[31][33] Triangulation is a technique used in many engineering applications to stiffen structures.[34] However doing so can also have undesirable effects if it overloads other parts of the frame, as a flexible frame acts as a spring to absorb some loads.[35]

Lateral stiffness

[edit]

In the 21st century, advances like high power engines driving high traction tires,[36] and better-performing suspension components, especially forks,[37] led to a situation where designs with increased overall frame stiffness were made available to consumers. Analysts differ on whether infinite lateral stiffness is desirable,[37] or whether a finite degree of built-in flex is preferable.[38][39]

Motorcycle frame measurement

[edit]
MotoSmartLaser
Front wheel axle deformation control.

If the handling of the motorcycle is not appropriate, it is important to check the deformation of the geometry of the motorcycle frame. This measurement can be important after an accident or before buying a used motorcycle.[citation needed]

See also

[edit]

References

[edit]

Sources

[edit]
Wikimedia Commons has media related to Motorcycle frames.
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Motorcycle frame

View on Grokipedia
from Grokipedia
The motorcycle frame is the core structural element of a , acting as the backbone that provides rigidity, supports the , transmission, suspension, components, and rider, while distributing forces to ensure stability, handling, and safety under various road conditions. It must balance strength, , and to optimize , with designs evolving from early tubular steel designs to modern engineered structures that influence the bike's , such as rake, , and . Key aspects of motorcycle frames include their diverse types, tailored to specific riding styles and performance needs. Common configurations encompass the spine or backbone frame, featuring a large-diameter tube as the central for simplicity and compactness; the single cradle frame, with a single top tube and down tube forming a loop around the ; the double or full cradle frame, using two down tubes for enhanced engine protection and rigidity; the perimeter or twin-spar frame, employing box-section beams running parallel to the ground for superior torsional stiffness in sport bikes; the trellis frame, composed of triangulated steel tubes for high strength-to-weight ratio and vibration damping; and the frame, where the external skin bears loads for integrated, lightweight designs in high-performance models. These types are selected based on requirements like load-bearing capacity, with frames undergoing finite element analysis (FEA) to verify stress limits (e.g., maximum von Mises stress under 202 MPa) and displacement (e.g., under 1.7 mm) during braking, cornering, and impacts. Materials for motorcycle frames prioritize a between , weight reduction, and manufacturability, with steels such as the mild steel S235 or the SAE AISI 4130 dominating due to their , high yield strength (around 460 MPa), and tensile strength (up to 560 MPa), enabling tube constructions that weigh as little as 13 kg for electric models. Aluminum alloys and advanced composites are increasingly used in premium applications for further weight savings—reducing overall vehicle to improve and —while maintaining safety factors of at least 3 against maximum forces like 2g bumps or 1g braking. Design principles emphasize iterative CAD to achieve ergonomic , resistance, and compliance with standards such as EN-1993 for structural , underscoring the frame's role in everything from commuter reliability to racing dynamics.

Overview

Definition and function

The motorcycle frame serves as the primary structural element of a motorcycle, acting as the core that connects the front suspension fork, the , and the rear to form a unified assembly. This integration ensures the vehicle maintains its overall geometry and supports the attachment of essential components such as the and bodywork via dedicated mounting points. The frame's primary functions are twofold: static and dynamic. In its static role, it bears the weight of the rider, passengers, engine, transmission, and accessories like fuel and oil tanks, providing foundational support under stationary or low-speed conditions. Dynamically, it works in tandem with the suspension and wheels to deliver precise steering, effective road holding, responsive handling, and rider comfort during motion. Overall, it imparts the necessary rigidity to withstand forces arising from acceleration, braking, cornering, and road impacts, while serving as mounting points for the engine, fuel tank, and bodywork. Through its , the frame manages load paths by distributing torsional stresses from cornering, lateral forces from leaning, and longitudinal loads from braking or acceleration, thereby preserving vehicle stability and rider control. The basic function of the frame resembles a , holding components in a rigid structure and transmitting forces between parts like the wheels and rider. In distinction from automobile chassis, which often feature heavy, separate ladder frames to support a body-on-frame construction, the motorcycle frame functions as the complete —integrating the and optimized for lightness to handle the unique balance and dynamics of two-wheeled vehicles.

Historical development

The earliest motorcycle frames, dating to the late 19th and early 20th centuries, closely resembled bicycle frames, with engines simply bolted into the structure for basic support. Manufacturers such as Indian and adopted diamond-shaped designs around the 1900s, prioritizing simplicity, low cost, and ease of production amid the growing power demands of early engines. These frames provided essential rigidity but often suffered from stress cracks under and . Post-World War II, frame engineering advanced significantly with the widespread adoption of tubular steel in the , enabling better strength-to-weight ratios and reduced flex compared to pressed steel. This era saw the rise of cradle frames, where the engine was supported by looping tubes for enhanced stability; British models like the of 1959 exemplified single- and double-cradle designs, balancing durability with improved handling for road use. Alloy integrations, including aluminum and refined steel, addressed vibration issues from heavier engines with integrated gearboxes. The and marked a shift toward performance-oriented innovations, particularly in Japanese sportbikes, where perimeter frames—featuring twin-spar beams parallel to the longitudinal axis—replaced traditional cradles to minimize torsional twist and boost cornering precision. The 1969 CB750 introduced a pressed backbone frame that laid groundwork for these evolutions, while models like Yamaha's FZR series employed aluminum perimeter designs for superior rigidity under high-speed braking and acceleration. , meanwhile, debuted its signature trellis frame in 1979 on the Pantah 500, using a lattice of welded tubes for lightweight stiffness that became a hallmark of Italian engineering. From the onward, racing demands accelerated the use of , with aluminum perimeter frames dominating production sportbikes for optimal and . transitioned its trellis concept to MotoGP in the early , achieving breakthroughs like the 2009 GP9's carbon fiber , which enhanced braking stability and over steel predecessors. Post-2010, designs gained traction in scooters—building on Vespa's longstanding pressed steel shells—and electric motorcycles, such as the 2019 NXT Rage.

Materials

Steel

Steel has long been the predominant material for motorcycle frames due to its balance of strength, affordability, and manufacturability. Common types include mild , often used in pressed or stamped frame designs for its ease of forming into complex shapes, and high-tensile alloys like 4130 chromoly for tubular constructions, which provide enhanced strength through the addition of and . Yield strengths for these steels typically range from 250 MPa for mild variants to 435-600 MPa for chromoly alloys, allowing frames to withstand significant loads while maintaining structural integrity. The advantages of steel frames stem from their high tensile strength, often exceeding 670 MPa in chromoly, which supports robust load-bearing capacity, and their , enabling the frame to flex and absorb crash energy like a spring without immediate . This energy absorption helps mitigate rider injury in impacts, making suitable for touring and models. Additionally, 's cost-effectiveness facilitates and repairs, as seen in the series, which has employed tubular frames since its 1984 debut to achieve a classic rigid look with hidden suspension. Despite these benefits, steel's high of approximately 7.8 g/cm³ results in heavier frames compared to modern alternatives, imposing weight penalties that reduce and in high-performance motorcycles. Without protective coatings such as zinc galvanization or , steel is susceptible to from moisture and road salt, potentially compromising longevity in harsh environments. Fabrication of steel frames primarily involves welding techniques like MIG (gas metal arc welding) for its speed and suitability on mild steel, and TIG (gas tungsten arc welding) for precise joints on thinner chromoly tubing, ensuring strong, clean connections that maintain frame geometry. Steel dominated motorcycle frame design from the early 20th century through the 1980s, when its prevalence began declining with the rise of lighter materials for performance gains.

Aluminum

Aluminum has become a preferred material for frames in high-performance applications due to its favorable strength-to-weight ratio, enabling enhanced agility and handling without excessive mass. This shift from traditional frames in and production bikes began in the late 1990s, driven by the need for lighter structures in competitive environments. Common alloys employed include the 6061-T6 and 7075 series, which offer tensile strengths ranging from 200 to 500 MPa and a density of approximately 2.7 g/cm³. These properties allow for 30-40% weight reductions compared to equivalent steel frames, significantly improving power-to-weight ratios in sport and off-road motorcycles. Key advantages of aluminum include superior corrosion resistance, which reduces maintenance needs in harsh conditions, and excellent thermal conductivity that aids in heat dissipation from the engine. Frames are often produced in cast or extruded forms, as seen in the perimeter-style Deltabox aluminum frame introduced on the Yamaha YZF-R1 in 1998, which prioritized rigidity and low center of gravity. Despite these benefits, aluminum exhibits lower strength than , necessitating design reinforcements such as gussets or thicker sections at stress points to mitigate cracking under repeated vibrations. Additionally, its higher material and fabrication costs, coupled with challenges in —often addressed via specialized techniques like to prevent weakening—limit its use in budget-oriented models. In applications, aluminum dominates sportbikes for its responsive handling, as exemplified by the Yamaha R1's ongoing use, and off-road motorcycles, where KTM adopted aluminum beam frames around 2000 for models like the SX series to balance durability and weight in rugged terrain.

Carbon fiber

Carbon fiber reinforced (CFRP) frames for motorcycles consist of embedded in an matrix, providing a lightweight with high performance characteristics. The themselves exhibit tensile strengths up to 3,500 MPa, Young's moduli ranging from 200 to 600 GPa, and a of approximately 1.6 g/cm³, enabling superior structural efficiency in the resulting CFRP. These properties translate to exceptional stiffness-to-weight ratios, allowing CFRP frames to achieve up to 50% weight reduction compared to equivalent aluminum designs while maintaining or exceeding rigidity. Additionally, CFRP offers inherent due to the viscoelastic nature of the epoxy matrix and arrangement, reducing rider on long rides or rough surfaces. In premium and racing applications, such as MotoGP, CFRP has been integrated into frames since the early , with examples including the carbon-fiber-coated frame used on Honda's RC213V in for enhanced handling. Despite these benefits, CFRP frames carry significant drawbacks, including high manufacturing costs often exceeding $1,000 per unit due to labor-intensive processes and premium materials. The material's under high-impact loads can lead to sudden, without prior deformation warning, unlike more ductile metals. Repairs are challenging and require specialized techniques like injection or patching, often necessitating professional intervention to restore structural integrity. Furthermore, CFRP's anisotropic nature—where mechanical properties vary by direction—demands precise orientations during fabrication to optimize strength in specific axes, complicating design and production. CFRP monocoque sections in motorcycle frames are typically manufactured using prepreg layup followed by curing, where heat (around 120-180°C) and (up to 6 bar) consolidate the laminate for void-free, high-strength bonds. Post-2020, adoption has grown in electric motorcycles, where CFRP's design flexibility facilitates seamless battery integration, such as embedding packs within the frame for improved and , as seen in models like the Arc Vector and Yamaha's TY-E trials prototype. For instance, the 2024 Ducati Superleggera V4 features a carbon fiber front frame for optimized performance.

Magnesium and titanium

Magnesium and titanium represent niche materials in motorcycle frame , employed primarily in high-performance, experimental, or custom applications due to their exceptional strength-to-weight ratios, though their adoption remains limited by high costs and complex processing requirements. These metals offer advantages over traditional or aluminum in specialized scenarios, such as off-road or environments, but their use in full frames is rare, often confined to prototypes or limited-production models. Magnesium alloys, such as AZ91D, are prized for their ultra-low of 1.81 g/cm³ and tensile strength ranging from 240-250 MPa, enabling significant weight savings in cast components. This material has been utilized in experimental motorcycle frames, notably in the 1974 Husqvarna 250 Magnesium, a lightweight bike designed for competitive racing with an all-magnesium integrated into the for enhanced rigidity and reduced mass. Advantages include its suitability for ultra-light crankcases that serve as stressed members within the frame, contributing to overall vehicle agility without sacrificing structural integrity. However, magnesium's poor —requiring specialized techniques to avoid defects—and inherent fire risk during machining or accidents limit its broader application, as the material can ignite readily and is challenging to extinguish. Titanium, particularly Grade 5 (), features a of 4.43 g/cm³ and impressive tensile strength of 900-1000 MPa, paired with superior resistance that prevents in harsh environments like off-road or marine conditions. Its high cost, often exceeding $25 per kg for industrial-grade material, and processing demands make it viable mainly for custom or prototype frames, such as those in Beta off-road motorcycles or the all- Hayabusa-based custom build, where the frame, , and subframe achieve 45% weight reduction over equivalents while maintaining durability. excels in longevity without degradation, ideal for demanding applications, but its high of 1668°C necessitates advanced methods like to purify and form the , adding to fabrication challenges and expense.

Composite materials

Composite materials for motorcycle frames, distinct from high-performance carbon fiber variants, encompass reinforced plastic (GFRP) and -based composites such as . GFRP consists of embedded in a matrix, typically or polyester resin, providing a cost-effective option. Aramid composites, like those using fibers, offer similar matrix systems but with enhanced toughness due to the fiber's molecular structure. These materials generally exhibit tensile strengths between 500 and 1500 MPa and densities of 1.5 to 2.0 g/cm³, making them lighter than traditional metals while maintaining sufficient load-bearing capacity for frame applications. A key advantage of these composites over carbon fiber is their lower production cost, which facilitates broader adoption in budget-conscious designs. -reinforced variants particularly excel in impact resistance, absorbing energy from collisions without , due to the fiber's high elongation at break. GFRP and composites have been integrated into scooter monocoques since the for lightweight structural support, and they appear in custom chopper frames where builders prioritize affordability and ease of molding over ultimate rigidity. For instance, fiberglass-reinforced kits enable bespoke chopper constructions with reduced weight compared to equivalents. Despite these benefits, non-carbon composites suffer from lower stiffness than carbon fiber, with GFRP's typically ranging from 20 to 40 GPa, limiting their use in high-performance racing frames that demand precise handling. Both materials are prone to UV degradation, where prolonged sunlight exposure breaks down the matrix, leading to reduced mechanical integrity and potential microcracking. To mitigate costs and weight in rugged applications, hybrid steel-composite frames—combining metallic substructures with GFRP or panels—have gained traction in adventure motorcycles since 2015, offering a practical compromise for off-road durability. In emerging electric designs, these composites provide inherent electrical insulation properties, aiding battery integration and reducing conductive risks, though full-frame adoption remains experimental as of the . Overall, GFRP and serve cost-sensitive and custom segments, where their impact resilience and moldability outweigh stiffness limitations.

Frame Types

Backbone frame

The backbone frame consists of a single, prominent upper tube extending from the steering head to the swingarm pivot, with the mounted directly below it for support. This design creates a straightforward structural spine that bears the primary loads from the rider, , and , often incorporating additional brackets or mounts for the without enclosing it in lower loops. One early example of this frame type appeared in the late on the CB92 Benly, a parallel-twin model, and it has since been employed in various singles and twins for its structural efficiency. The configuration offers advantages such as compactness and reduced weight due to minimal material usage, enabling a direct load path that enhances overall balance in smaller-displacement bikes. However, it can exhibit potential flex under high loads and provides limited access to the for , as the upper tube obstructs top-side servicing. Variations typically use tubing for durability in entry-level models, though aluminum variants appear in performance-oriented applications for further weight savings; rear subframes are commonly added to support the , suspension, and bodywork without compromising the main spine's integrity.

Cradle frames

Cradle frames are a traditional characterized by tubular structures that form loops to support and enclose the , providing a secure mounting point while distributing stresses effectively. These frames typically extend from the steering head, curve around the , and connect to the pivot, offering a balance of simplicity and robustness suitable for street and sport applications. The evolved from early bicycle-derived frames, with variants differing in the number and configuration of tubes to optimize protection, rigidity, and weight. The single cradle variant features a single downtube and main pipe extending from the steering head to form an open lower loop around the , leaving the lower portion partially exposed for easier access and reduced weight. This configuration provides basic support but offers less enclosure than more complex designs. Examples include early 1970s Yamaha models like the DT series trail bikes, which utilized this layout to accommodate off-road durability while keeping manufacturing costs low. In contrast, the double cradle frame employs two downtubes that fully enclose the engine from the steering head, creating a complete loop for enhanced protection against impacts and improved structural integrity. A notable example is the 1972 , which used a double tubular steel cradle frame to support its powerful four-cylinder engine, ensuring stability under high-speed conditions. This variant, including the half-duplex subtype with partial lower tube support for added reinforcement without full duplication, excels in safeguarding multi-cylinder engines by distributing loads evenly and minimizing vibration transmission. However, the additional tubing increases manufacturing complexity and overall weight compared to simpler designs. The full duplex cradle takes this further with twin upper and lower tubes forming paired cradles on either side of the , significantly boosting torsional rigidity for superior handling and . While ideal for high-performance multi-cylinder setups due to its robust enclosure and load-bearing capacity, the design's added material contributes to higher weight and assembly complexity, potentially impacting agility in modern applications.

Perimeter frame

The perimeter frame, also referred to as the twin-spar frame, consists of two spars extending directly from the steering head to the pivot, with the positioned as a central structural component. This beam-like configuration creates a compact that encircles the powerplant minimally, optimizing the structural path for load transfer and enhancing overall handling precision in sportbikes. The advantages of the perimeter frame include a shortened that promotes nimble maneuverability and responsive cornering, alongside superior torsional rigidity that maintains stability under dynamic loads. Aluminum quickly became the predominant material, as seen in the 1985 , whose box-section alloy frame delivered approximately 60% greater rigidity than contemporary designs while reducing weight for better . However, the design presents challenges, such as constrained packaging space around the engine, which limits accommodation of larger displacement units, and elevated production costs stemming from the precision welding and machining required for aluminum components. Unlike the trellis frame, which relies on interconnected tubes for tailored strength distribution, the perimeter frame employs solid spars for straightforward rigidity and simpler fabrication. Since the , the perimeter frame has established itself as the benchmark for supersport motorcycles, driving widespread adoption across manufacturers for its balance of performance and efficiency. Its influence extended to off-road segments, notably in models like the KTM EXC series, where similar twin-spar principles enhance durability and control in rugged terrain.

Trellis frame

The trellis frame consists of interconnected steel tubes, often made from chromium-molybdenum alloy for enhanced strength-to-weight ratio, arranged in a lattice or diamond-like pattern that envelops the while connecting the head directly to the pivot. This design, pioneered in high-performance motorcycles, allows for precise load distribution through triangulated tubing that mounts to multiple points on the cases. A seminal example is the 1991 900SS, which utilized a steel trellis frame to achieve agile handling around its air-cooled . One key advantage of the trellis frame is its tunable , achieved by varying tube diameters, wall thicknesses, and placement to balance rigidity and flexibility for specific riding dynamics. This customization results in a yet robust that excels in and , making it particularly suitable for air-cooled engines where around the cylinders is essential. Compared to perimeter frames, the trellis prioritizes an open tubular network for superior control over the spar efficiency of perimeter designs. However, the trellis frame's construction involves labor-intensive hand-welding of numerous tubes, demanding skilled craftsmanship and leading to higher and repair costs relative to pressed alternatives. The trellis frame has become iconic in Italian sportbikes, notably in models from the 1990s onward and MV Agusta's lineup, where it remains a hallmark for performance-oriented machines. In the 2010s, manufacturers like MV Agusta adapted the design by incorporating aluminum alloy side plates and pivot elements alongside the steel trellis for further weight reduction while preserving structural integrity.

Monocoque and semi-monocoque frames

Monocoque frames in motorcycles consist of a single-piece shell structure, typically constructed from aluminum or composite materials, that bears all structural loads without relying on a separate tubular or beam framework. This design integrates the chassis and bodywork into one unit, providing exceptional torsional rigidity while minimizing weight. The concept draws from aerospace engineering, where the outer skin distributes forces evenly, and was first explored in motorcycles during the 1970s with experimental aluminum constructions. A seminal example is the 1972 welded-aluminum frame designed by Eric Offenstadt, which prioritized lightness and stiffness over traditional steel tubing, influencing later developments like the 1980 Kawasaki KR500's aluminum box-beam . In production models, Honda's NR750 from 1992 featured an aluminum frame paired with its innovative oval-piston , achieving high rigidity for superior handling despite limited production due to manufacturing challenges. More recently, Ducati's Panigale series, starting with the 2012 1199, employs a aluminum front frame that incorporates the airbox and uses the engine as a stressed member, reducing overall weight by approximately 10 pounds compared to trellis designs. For electric motorcycles, the Damon HyperSport HS utilizes a carbon fiber that encases the battery and motor, enhancing compactness and for high-performance applications. Semi-monocoque frames build on the principle but incorporate internal reinforcements, such as ribs or spars, to support the stressed outer skin, allowing for greater load distribution and durability in high-impact scenarios. This hybrid approach is common in modern sportbikes and scooters, where the skin—often pressed aluminum or composite—works in tandem with underlying structures to achieve balance between rigidity and flexibility. The Buell XB series, introduced in 2003, exemplifies this with its aluminum plate construction that integrates the as a , using stamped panels and reinforcements to form a compact weighing around 40 pounds. These designs offer key advantages, including reduced part count for simpler assembly, improved through seamless integration, and suitability for compact like scooters and electric bikes, where space efficiency is paramount— models have long used pressed-steel shells for urban mobility. However, they present challenges: repairs are complex and costly due to the integrated nature, often requiring specialized tools or full replacement, and the structures can be vulnerable to crash damage, as seen in early experiments that flexed excessively at high speeds. demands precision molding or , increasing production costs and limiting adoption in full-size touring models, where tubular frames provide better crash energy absorption.

Design Considerations

Engine as stressed member

In motorcycle design, the engine serves as a stressed member when its casing functions as a load-bearing , directly transmitting forces and torques to the rather than merely being suspended within it. This integration typically involves bolting the engine's upper and lower to the frame's extremities, effectively making the engine a central component of the overall structure. Early examples include the British Vincent HRD models of the 1940s, such as the Black Shadow, where the was incorporated as a stressed member to minimize frame complexity and enhance rigidity. This approach gained prominence in the 1960s through British racing frames, like those designed by Colin Seeley for engines, which utilized the powerplant as a stressed element to achieve lighter, more rigid constructions for superior handling on the track. By the 1970s, Japanese manufacturers adopted the concept, as seen in models like the , where the inline-six engine was integrated as a stressed member to distribute loads effectively. The design evolved further in the 1990s with Japanese superbikes, such as the , marking the first production motorcycle to fully integrate the engine as a stressed member in an aluminum Deltabox frame, which improved mass centralization and performance. The primary advantages of using the as a stressed member include significant weight reductions—often the largest single saving in design—and a simpler overall structure that enhances handling by lowering the center of gravity and stiffening the bike. This method became standard in perimeter and trellis frames, exemplified by modern models like the Panigale V2, where the Desmosedici Stradale acts as a load-bearing component within the trellis, contributing to agile dynamics without excess tubing. However, drawbacks include increased transmission to the rider due to the lack of isolating rubber mounts, potential engine case cracking from crash impacts or improper loading (such as on a ), and the need for robust materials to withstand torsional stresses. In contemporary adaptations, particularly for electric motorcycles, battery packs fulfill a similar role as stressed members, providing structural integrity while housing . For instance, the SR/F integrates its Z-Force pack as a stressed member within the tubular steel-trellis frame, reducing overall weight and optimizing space efficiency. Similarly, the employs the mounted directly to the motor and , treating it as a component to optimize efficiency and durability in electric designs.

Stiffness and rigidity

Stiffness in frames refers to the resistance to deformation under load, encompassing torsional, lateral, and vertical that critically influence handling, stability, and rider comfort. Torsional measures resistance to twisting forces, which is essential during cornering to maintain precise control and prevent weave or wobble oscillations. Lateral addresses sideways bending, aiding in stability under lean angles and braking. Vertical , conversely, involves controlled compliance to absorb road bumps, reducing vibrations transmitted to the rider while avoiding excessive flex that could compromise control. These are typically quantified in Nm/deg for torsional and lateral , reflecting per unit angular or linear deformation. Key factors influencing frame include tube diameter and wall thickness, which determine the section's resistance to and torsion, as well as overall , such as tube arrangement and , which affect load distribution. For a basic tubular member, torsional KK can be approximated by the equation K=GJLK = \frac{GJ}{L} where GG is the of the material, JJ is the polar (dependent on tube cross-section), and LL is the effective . Larger diameters significantly increase JJ, enhancing without proportionally adding weight, while thicker walls provide additional strength but may reduce compliance. plays a pivotal role; for instance, triangulated designs like trellis frames distribute loads more evenly, yielding higher torsional values compared to simpler backbone layouts. The importance of frame lies in balancing rigidity for sharp handling and stability against sufficient compliance for a smooth ride over uneven surfaces. Excessive rigidity can lead to harsh feedback and reduced traction on bumps, while insufficient stiffness causes during aggressive maneuvers. In high-performance applications, such as modern 1000cc racing motorcycles, torsional stiffness is typically tuned to 3,000–7,000 Nm/deg to optimize cornering precision and of dynamic modes like wobble. This balance ensures the frame contributes to overall without overwhelming the suspension's role in vertical compliance. Since the , finite element (FEA) has become a cornerstone tool for simulating and optimizing frame , allowing engineers to predict torsional, lateral, and vertical behaviors under various loads before physical prototyping. FEA models incorporate , material properties, and boundary conditions to iterate designs efficiently, as seen in early applications for racing frames where shell and beam elements refined targets for enhanced performance.

Geometry and measurements

The geometry of a motorcycle frame encompasses critical dimensions that directly influence the vehicle's handling characteristics, particularly stability and response. Key measurements include the , which is the horizontal distance between the front and rear centers, typically ranging from 1220 to 1650 mm across various types, with longer lengths enhancing straight-line stability at the expense of agility. For example, touring models like the R 1250 RT feature a of 1485 mm to prioritize load-carrying stability, while sportbikes often employ shorter wheelbases around 1400 mm for quicker cornering. The length, measured from the pivot point to the rear , generally falls in the 500-600 mm range, contributing to rear suspension geometry and traction by affecting weight distribution during acceleration. Rake and trail are pivotal front-end measurements that govern behavior. Rake refers to the angle of the head axis relative to vertical, commonly between 22° and 32° in motorcycles, with steeper angles (closer to vertical) promoting quicker for sport-oriented riding and shallower angles favoring high-speed stability in cruisers. , the horizontal distance from the front tire's to the point where the axis intersects the ground, typically measures 80-100 mm in sportbikes for balanced quickness and stability, increasing to 150 mm or more in cruisers for enhanced straight-line composure. This dimension balances effort: shorter trail enables rapid direction changes but can reduce stability, while longer trail improves self-centering but demands more input for turns. The relationship between rake and can be quantified using the mechanical trail formula: Trail=rcos⁡ϕ−dsin⁡ϕ\text{Trail} = \frac{r \cos \phi - d}{\sin \phi} where rr is the front radius (including tire), ϕ\phi is the , and dd is the fork offset (distance from the steering axis to the wheel centerline). This equation illustrates how adjustments in rake or offset alter , thereby tuning the trade-off between steering quickness and high-speed stability without compromising overall frame integrity. Assessment of these geometries relies on advanced methods to ensure optimal performance and . (CAD) modeling allows engineers to simulate dimensional interactions and predict handling dynamics iteratively, often integrated with multi-body dynamics software for virtual ing. Physical prototyping follows, involving fabricated frames tested under load to validate simulations and refine measurements. Since the , international standards such as ISO 13232 have guided evaluations, specifying crash procedures that incorporate geometric factors like and rake to assess rider protection, though they emphasize overall vehicle kinematics rather than prescriptive dimensional limits.

Manufacturing and Testing

Construction techniques

Motorcycle frames are fabricated using a range of techniques tailored to the frame type, material, and production scale, emphasizing precision to ensure structural integrity and performance. Traditional methods focus on tube manipulation for steel-based designs, while modern approaches leverage advanced forming for lighter materials like aluminum and titanium. Trellis frames, common in sportbikes, are constructed from steel tubes that are first bent into curved sections using hydraulic mandrel benders to maintain wall thickness and avoid wrinkling. The bent tubes are then cut to length, mitered for fit, and joined primarily through welding in production settings, though brazing with filler alloys like silver or brass is employed in custom or high-performance builds for smoother joints and reduced heat distortion. Aluminum perimeter frames, prevalent in modern superbikes, utilize to produce long, uniform main spars with integrated cross-sections for stiffness, followed by at critical junctions like the steering head and pivot to create complex geometries that distribute loads effectively. High-pressure with alloys such as A356 ensures tight tolerances and seamless integration, reducing the need for extensive . Since the early 2000s, has emerged as a key technique for steel frames, particularly in perimeter and cradle designs, where high-pressure expands tubes inside dies to form intricate shapes like tapered down tubes and reinforced sections without welds, resulting in lighter, stronger structures with significant weight reduction compared to stamped alternatives. This process, adopted by manufacturers like for models such as the V-Rod in 2001, allows for complex contours that enhance rigidity while minimizing material use. Welding techniques are selected based on material properties to achieve durable joints. Tungsten inert gas (TIG) is standard for frames due to its precise heat control, which prevents and warping in the reactive metal; clean preparation, shielding, and low amperage (typically 45-55A for 0.035-inch tubing) are essential for full penetration without oxidation. Laser provides high precision for composite-integrated frames, such as those combining carbon fiber reinforcements with metal substructures, offering minimal heat-affected zones and distortion for thin sections. Jigs and fixtures, often modular assemblies with adjustable clamps and alignment pins, ensure accurate positioning during , maintaining rake and angles within 0.5 degrees. Assembly processes differ between custom and mass production. In custom builds, modular subframes—detachable rear sections fabricated from bent tubing and bolted to the main cradle—allow for tailored seating and exhaust configurations, facilitating easier modifications like cafe racer conversions. employs , such as robotic systems at facilities like Honda's plant, where such systems ensure efficient and consistent seam quality. Quality control during construction incorporates non-destructive testing to verify weld integrity without compromising the frame. radiography is widely used to detect internal defects like or cracks in welds, with high-resolution 2D systems for efficient scanning of , ensuring compliance with standards such as ISO 6520 for automotive-grade frames. As of , additive manufacturing techniques, such as , are increasingly used for prototyping and custom frames to enable complex geometries and further weight savings.

Performance evaluation

Performance evaluation of motorcycle frames involves a series of standardized and experimental tests to assess structural integrity, long-term durability, and dynamic handling characteristics under simulated and real-world conditions. These protocols ensure frames can withstand operational stresses without compromising safety or performance, drawing from international standards and practices. Key tests include static load assessments, dynamic cycling, and crash simulations to verify the frame's ability to support vehicle components and riders during various scenarios. Static load tests evaluate the frame's capacity to handle concentrated forces, such as loads equivalent to 1.5–2 times the gross (e.g., around 2000–3000 N including rider and components) at critical points like the footpegs or to simulate maximum braking or . These tests measure resistance to deformation, ensuring the frame maintains alignment and stability under peak static conditions. Dynamic fatigue tests subject the frame to repeated cyclic loading, typically up to 10^6 cycles at frequencies mimicking vibrations, to predict lifespan and identify potential crack initiation sites. Crash simulations follow ISO 13232 protocols, involving full-scale impact tests at speeds up to 50 km/h into fixed barriers or angled surfaces to assess frame deformation and energy absorption without . Testing methods incorporate for precise data collection, including strain gauges affixed to high-stress areas like welds and tube junctions to monitor micro-deformations during loading. Shaker tables replicate profiles, applying multi-axis excitations up to 100 g acceleration to evaluate and in components such as frame-mounted batteries on electric motorcycles. For handling assessment, real-world track testing correlates frame with performance metrics, where optimized designs reduce times by improving cornering stability and responsiveness on circuits like . influences test setups by defining load application points, as detailed in related measurements. Performance metrics focus on quantifiable thresholds for acceptance. Acceptable lateral deflection under full load is limited to minimal values to prevent handling , while natural frequencies are targeted above 10 Hz to avoid with engine or road inputs, often achieving values around 200 Hz in modern designs. These benchmarks ensure the frame contributes to overall without excessive flex. In the 2020s, advancements in digital twins—virtual replicas integrating real-time sensor data with finite element models—have enabled predictive testing for electric frames, simulating millions of cycles virtually to optimize battery integration and reduce physical prototyping. AI algorithms further enhance this by automating load spectrum analysis and failure prediction, accelerating development for lightweight electric structures while maintaining durability standards.

References

  1. https://www.ijirset.com/upload/2017/october/39_Design1.pdf
  2. https://lutpub.lut.fi/bitstream/10024/164604/3/kandi_Tomi_Suikkari_final.pdf
  3. https://www.ijsrd.com/articles/IJSRDV7I40351.pdf
  4. https://www.sae.org/publications/technical-papers/content/2017-01-1855/
  5. https://www.irjet.net/archives/V7/i9/IRJET-V7I9217.pdf
  6. https://www.rideapart.com/features/254262/history-of-motorcycle-frames/
  7. https://www.revzilla.com/common-tread/why-things-are-the-way-they-are-frame-design
  8. https://www.thehindubusinessline.com/specials/auto-focus/the-history-of-motorcycle-frames/article23029421.ece
  9. https://www.ducati.com/ww/en/heritage/bikes/trellis-frame
  10. https://www.crash.net/motogp/feature/145397/1/ducatis-carbon-fibre-motogp-chassis
  11. https://www.designboom.com/technology/nxt-motors-unveils-electric-motorcycle-with-carbon-rage-fiber-monocoque-02-19-2019/
  12. https://www.aecc.eu/legislation/motorcycles-and-mopeds/
  13. https://www.jswonemsme.com/blogs/blogs-articles/cracking-the-motorcycle-code-5-important-steels-used-in-two-wheelers
  14. https://www.astmsteel.com/steel-knowledge/4130-alloy-steel/
  15. https://www.unionfab.com/blog/2024/03/4130-vs-4140
  16. https://www.motorcycledaily.com/2003/05/21may03steeltrellisframe/
  17. https://www.revzilla.com/common-tread/forty-years-and-counting-the-story-behind-harleys-softail-line
  18. https://bikethomson.com/blog/different-bike-frame-materials-explained/
  19. https://spokester.com/blogs/news/bike-frame-materials-pros-and-cons
  20. https://www.thefabricator.com/thewelder/article/arcwelding/welding-a-motorcycle-frame-advice-from-an-expert
  21. https://www.millerwelds.com/resources/article-library/tig-welding-chromoly-steel-5-tips-to-improve-results
  22. https://oldbikebarn.com/blogs/blog/advancements-in-motorcycles-alloy-frames
  23. https://www.cycleworld.com/everything-youve-ever-wanted-to-know-about-aluminum/
  24. https://www.chinalcometal.com/blog/aluminum-6061-t6-vs-7075/
  25. https://www.quora.com/What-are-the-advantages-of-steel-motorcycle-frames-over-aluminium-frames
  26. https://www.twi-global.com/technical-knowledge/published-papers/friction-stir-welding-of-aluminium-alloys/
  27. https://www.thumpertalk.com/forums/topic/505878-ktm-alu-frame/
  28. https://www.thomasnet.com/articles/plastics-rubber/carbon-fiber-reinforced-polymers-cfrp/
  29. https://www.researchgate.net/figure/Properties-of-carbon-fiber-reinforced-polymer-CFRP_tbl3_342938721
  30. https://www.azom.com/article.aspx?ArticleID=1995
  31. https://triaero.com/blogs/news/is-carbon-fibre-better-than-aluminum
  32. https://www.smicomposites.com/roads-and-mountains-how-to-go-further-with-a-carbon-fiber-bike-frame/
  33. https://www.motorsportmagazine.com/articles/motorcycles/motogp/carbon-fibre-motogp-it-s-long-story/
  34. https://www.customfighters.com/threads/carbon-fiber-frame.262/
  35. https://carboncraftx.sg/pages/carbon-fiber-0005-advantages-and-disadvantages-of-carbon-fiber-composites-in-bicycles
  36. https://icancycling.com/blogs/articles/the-things-you-should-know-repair-carbon-bike
  37. https://goodwinds.com/carbon-fiber-is-anisotropic-heres-why-thats-awesome/
  38. https://www.samgeorgal.com/2022/10/carbon-fiber-monocoque-chassis.html
  39. https://www.cycleworld.com/arc-vector-electric-motorcycle-to-go-into-production-in-2020/
  40. https://global.yamaha-motor.com/design_technology/technology/news/TY-E/
  41. https://www.bikenrider.com/feature/ducati-superleggera-v4
  42. https://www.bikeradar.com/advice/buyers-guides/bike-frame-materials
  43. https://www.boxrepsol.com/en/motogp-en/magnesium-and-titanium-lightweight-materials-used-in-motogp/
  44. https://www.azom.com/article.aspx?ArticleID=9219
  45. https://www.rideapart.com/articles/425152/1974-husqvarna-250-mag-for-sale/
  46. https://www.cycleworld.com/2013/10/08/developments-in-magnesium-part-2/
  47. https://www.pentonusa.org/9-dos-and-donts-of-magnesium/
  48. https://primeweld.com/blogs/news/properties-of-magnesium-for-welding
  49. https://asm.matweb.com/search/specificmaterial.asp?bassnum=mtp641
  50. https://www.unionfab.com/blog/2024/03/ti6al4v-density
  51. https://wozo.com/industrial-titanium-cost-per-kg-2025-supplier-guide/
  52. https://www.thumpertalk.com/forums/topic/1421311-5-118-lb-titanium-beta-frames-just-built/
  53. https://newatlas.com/motorcycles/all-titanium-motorcycle/
  54. https://www.kobelco.co.jp/english/products/advanced-materials/about-titan/process/forging.html
  55. https://eupegypt.com/blog/fiberglass-vs-carbon-fiber-reinforced-plastic/
  56. https://www.engineeringtoolbox.com/polymer-composite-fibers-d_1226.html
  57. https://www.researchgate.net/figure/Basic-mechanical-properties-of-Kevlar-and-basalt-fibers_tbl1_359592228
  58. https://www.fibreglast.com/collections/kevlar-r
  59. https://mahanrasouli.com/composite-materials-motorcycle-design/
  60. https://www.flyritechoppers.com/Pg/FRCFrameChassis.html
  61. https://www.quora.com/What-are-the-pros-and-cons-of-hybrid-carbon-fiber-and-Kevlar-composites-vs-carbon-fiber-composites
  62. https://performancecomposites.com/are-all-marine-fiberglass-panels-uv-resistant-by-default/
  63. https://www.researchgate.net/publication/365013121_Design_and_Analysis_of_Electric_Bike_Chassis_Using_Glass_Fibre_Composites
  64. https://roberts.com.ph/blog/understanding-types-motorcycle-chassis/
  65. https://deshibiker.com/backbone-frame-of-motorcycle/
  66. https://www.bikedekho.com/news/different-types-of-motorcycle-chassis-explained
  67. https://www.g-w.com/assets/files/pdf/sampchap/9781685844486_Ch18.pdf
  68. https://www.youtube.com/watch?v=-91_Sz_74JE
  69. https://www.motorcyclespecs.co.za/model/kawasaki/kawasaki_z1%252072.htm
  70. https://www.tvsmotor.com/media/blog/decoding-the-different-types-of-motorcycle-chassis/
  71. http://www.bbrmotorsports.com/Gallery/Photos/Photos.aspx
  72. https://www.motorcycle.com/manufacturer/suzuki/suzuki-gsxr-history-91551.html
  73. https://www.bikeleague.in/motorcycle-articles/motorcycle-technical-articles/bike-chassis-which-is-right-for-your-riding-style/
  74. https://deshibiker.com/twin-spar-or-perimeter-frame/
  75. https://www.cycleworld.com/why-ducatis-trellis-frame-was-so-good/
  76. https://www.ktm.com/en-us/tech-guide/chromium-molybdenum-steel-trellisframe.html
  77. https://www.autoevolution.com/moto/ducati/900-1/
  78. https://www.zx4rforum.com/threads/zx4r-frame-steel-trellis-vs-twin-spar-aluminium.2456/
  79. https://www.icicilombard.com/blogs/two-wheeler-insurance/bike/trellis-frame-in-a-motorcycle
  80. https://www.hdfcergo.com/blogs/two-wheeler-insurance/what-is-trellis-frame-in-bike
  81. https://www.asphaltandrubber.com/bikes/2010-mv-agusta-f4/
  82. https://www.totalmotorcycle.com/photos/2010models/2010-MVAgusta-F4/
  83. https://www.cycleworld.com/story/blogs/ask-kevin/motorcycle-inventions-technology-problem-solving/
  84. https://global.honda/en/heritage/episodes/1979pistonengine.html
  85. https://www.ducati.com/us/en/bikes/panigale/panigale-v2
  86. https://damon.com/blog/how-damon-hyperdrive-is-changing-everything-we-know-about-electric-motorcycle-design/
  87. https://www.asphaltandrubber.com/bikes/hondas-forgotten-frameless-chassis-design-patent/
  88. https://thekneeslider.com/monocoque-motorcycle-chassis-possibilities/
  89. https://silodrome.com/history-vincent-black-shadow/
  90. https://www.vintagemotorcycles.nl/vincent/
  91. https://anthonygodin.co.uk/car/seeley-triumph-t120-bonneville/
  92. https://magazine.cycleworld.com/article/1979/1/1/honda-cbx
  93. https://www.hotcars.com/5-fastest-japanese-motorcycles-of-the-90s-and-5-american-wed-rather-buy/
  94. https://www.cycleworld.com/bikes/ducati-panigale-v2-and-streetfighter-v2-first-look/
  95. https://www.motorbiscuit.com/what-does-it-mean-when-an-engine-is-a-stressed-member/
  96. https://www.cycleworld.com/2020-zero-sr-f-electric-motorcycle-first-ride/
  97. https://www.emobility-engineering.com/lightning-strike-electric-motorcycle/
  98. https://www.bottpower.com/measuring-frame-stiffness/
  99. https://www.researchgate.net/publication/285345735_Static_and_dynamic_properties_of_a_motorcycle_frame_Experimental_and_numerical_approach
  100. https://www.omnicalculator.com/physics/torsional-stiffness
  101. https://www.dpublication.com/wp-content/uploads/2020/12/19-20128.pdf
  102. https://spanner.bike/?p=2016
  103. https://www.[researchgate](/page/ResearchGate).net/publication/285345735_Static_and_dynamic_properties_of_a_motorcycle_frame_Experimental_and_numerical_approach
  104. https://www.irjet.net/archives/V8/i7/IRJET-V8I7811.pdf
  105. https://repositorio-aberto.up.pt/bitstream/10216/88605/2/32524.pdf
  106. https://www.cycleworld.com/story/blogs/ask-kevin/how-the-motorcycle-wheelbase-affects-handling/
  107. https://r1250rt.com/specifications/
  108. https://ofstandard.com/general/standard-dimensions-of-motorcycle
  109. https://www.triumphrat.net/threads/swing-arm-length.197276/
  110. https://www.superhawkforum.com/forums/technical-discussion-28/swingarm-measurements-comparisons-17027/
  111. https://ridermagazine.com/2009/06/30/understanding-motorcycle-rake-and-trail/
  112. https://www.motorcyclemojo.com/2014/06/chassis-geometry/
  113. https://www.customfighters.com/threads/motorcycle-rake-and-trail-from-sportrider-com.48959/
  114. https://www.cycleworld.com/2015/05/22/cycle-world-tips-and-tricks-understanding-motorcycle-rake-and-trail/
  115. https://www.datamc.org/downloads/motorcycle-rake-and-trail-calculator/
  116. https://asiachapter.designsociety.org/download-publication/29601/Virtual%2BPrototyping%2BSimulation%2Bfor%2Bthe%2BDesign%2Bof%2BTwo-Wheeled%2BVehicles
  117. https://www.sciencedirect.com/science/article/pii/S0001457520317772
  118. https://www.caferacerwebshop.com/en/blogs/blog/how-to-bend-tubes-and-frames-by-yourself/
  119. https://www.customfighters.com/threads/anybody-know-about-tig-brazing.60099/
  120. https://www.cycleworld.com/story/blogs/ask-kevin/how-cast-aluminum-chassis-became-possible/
  121. https://americanhydroformers.com/tubular-hydroforming-motorcycle-frame-manufacturing/
  122. https://www.thefabricator.com/tubepipejournal/article/tubepipefabrication/automotive-hydroforming-project-goes-start-to-finish-without-a-hitch
  123. https://www.weldingtipsandtricks.com/titanium-bike.html
  124. https://patents.google.com/patent/JP5911074B2/en
  125. https://www.chopsource.com/full-motorcycle-frame-jig-kit-welding-jig-fixture.html
  126. https://cafe4racer.eu/en/54-subframe-hoop-frame-cafe-racer-hand-made-crafted-subframes-for-motorcycle-builds
  127. https://global.honda/en/about/history-digest/75years-history/pdf/chapter3_1.pdf
  128. https://www.youtube.com/watch?v=tRuqb6wquig
  129. https://metrology.news/high-precision-2d-x-ray-technology-ensures-high-quality-motorcycle-parts/
  130. https://atslab.com/inspection/inspection-services/weld-x-ray-inspections/
  131. https://www.accio.com/business/trend-in-motorcycle-frame
  132. https://www.irjet.net/archives/V8/i6/IRJET-V8I6826.pdf
  133. https://www.cycleworld.com/story/blogs/ask-kevin/motorcycle-chassis-and-ductility/
  134. https://www.researchgate.net/publication/272065014_Durability_Analysis_of_Motorcycle_Frame_Using_Fatigue_I-Kaz_Technique
  135. https://www.sciencedirect.com/science/article/pii/S037877532201518X
  136. https://www.sciencedirect.com/science/article/pii/S2590123025036679
  137. https://www.witpress.com/Secure/elibrary/papers/CMEM05/CMEM05050FU.pdf
  138. https://www.researchgate.net/publication/371289890_Digital_twins_for_automotive_development_Two_wheelers_application
Add your contribution
Related Hubs
User Avatar
No comments yet.