FTS-402:
Re-Design of Chassis and Fairings for ICE-to-E Motorbike Conversion
Table of Contents
Acknowledgements
We would like to express our sincere gratitude to Mr Lim Hong Wee, our project supervisor, for his continuous guidance, valuable feedback, and encouragement throughout the development of this project. His technical advice and insights greatly enhanced the quality of our work.
Special thanks to our industry partner, Red Dot Mobility, and in particular to Mr Chun Lei, for his professional support and practical input regarding powertrain systems of electric vehicles, battery integration, and real-world e-bike design considerations. His expertise provided an important bridge between academic theory and industry application.
Summary
This project focuses on the conversion of conventional internal combustion engine (ICE) sports bikes into its electric derivative. The primary objective includes the design of chassis and fairing system that accommodates the electric vehicle (EV) powertrain specified by our industry partner, Red Dot Mobility.
The redesigned chassis is engineered to integrate key electronic components such as the motor, controller, and battery pack, while keeping structural integrity in mind. Building upon the chassis foundation, subsequent design phase explores the development of the fairing system with aerodynamics in mind.
Undertaken over two academic semesters by a team of three mechanical engineering students, aims to employ Finite Elemental Analysis (FEA) and Computational Fluid Dynamics (CFD) on Solidworks & ANSYS to validate the structural and aerodynamic performance.
1. Objective & Scope
This project addresses the challenge of mechanically realising the conversion of an existing 650cc ICE sports bike to its electric derivative. The EV powertrain provided by Red Dot Mobility, which includes motor, controller and battery, establishes a fixed set of geometric, load-bearing constraints and top speed of 220-250km/h. Within these parameters, the project focuses on the structural and aerodynamic redesign: namely chassis and fairing.
The scope of this project is limited to the chassis and fairing redesign. For the chassis, the project considers battery packaging, geometry, and powertrain mounting. For the fairing, the project considers aerodynamics, aesthetic. The project does not cover motor development, battery chemistry development, or full homologation testing.
2. Context of Problem
EV sales in South East Asia are set to approach 30% of all vehicle sales in 2030 under today’s policy settings (International Energy Association, 2025). Back home, Singapore’s Green Plan 2030 targets a fully cleaner-energy vehicle fleet by 2040 (Land Transport Authority, 2025). Despite this momentum, the local electric motorcycle sector remains small and segmented.
At the premium end of Singapore’s electric motorcycle market, Energica is available through a sole distributor, Ifyni Pte Ltd, and Zero Motorcycles is represented exclusively by Mah Pte Ltd (Ifyni, 2025; Mah, 2025). These arrangements often lead to limited availability and high price points, positioning both brands as niche products for affluent enthusiasts. Meanwhile, local manufacturers such as Scorpio Electric and ION Mobility target commuters to mid-performance segments, focusing on everyday city use rather than the sporty, high-performance category. This leaves a clear gap in the local market: riders who want a sporty electric motorcycle face premium prices and limited supply at the top end, while commuter models fall short on performance and feel. Working with Red Dot Mobility, our project addresses this middle space by targeting an electric sports bike that delivers performance and handling at a reachable price, with reliable local support in Singapore.
Problem Statement:
How can we convert an existing ICE sports motorcycle into its electric derivative within the practical limits of cost, time, and manpower while ensuring safety, functionality, and integration of fixed components supplied by Red Dot Mobility.
3. Concept Development
Upon assessment of the donor components, the chassis and fairings were selected for a redesign. For the full systematic evaluation and decision-making process, see Appendix A.
In this section, we will detail the chassis and fairing concept exploration.3.1 Chassis Concept Exploration
The initial concept evaluation of the structure and material of chassis can be seen in Figure 3.1.1
Initially, the welded steel trellis chassis was selected for its balance of structural rigidity, manufacturability, and cost-effectiveness (Kulkarni, C., & Kanthale, V. S., 2024). However, further design evaluation revealed several practical limitations. The chassis mass was comparatively high, at approximately 20 kg, which introduces a significant penalty in terms of energy consumption and overall vehicle efficiency.
In addition to its weight disadvantage, the welded truss structure presented manufacturing and structural concerns. Welded joints are sensitive to distortion, alignment error, and heat-affected property changes, which can reduce dimensional accuracy and complicate assembly. As the design matured, these issues made the truss concept less suitable for a lightweight, high-efficiency chassis.
Once these limitations were identified, a bonded aluminium chassis became a more convincing alternative. The key advantage was not simply that aluminium is lighter, but that the extrusion-and-bonding approach allows the material to be used more efficiently in a structural sense. The hollow extrusion geometry provides good stiffness without unnecessary mass, while epoxy bonding offers distributed load transfer and avoids heat-affected problems associated with welding.
The revised bonded aluminium concept was further supported by industry precedent. Lotus successfully demonstrated bonded aluminium chassis construction, showing that adhesive bonding can offer dimensional precision, reduced heat-affected damage, and improved load distribution compared with welding (Lotus, 2026). Based on this review, the design direction was revised from a steel truss to a bonded aluminium frame.
The concept selection will be further justified by comparing the structural characteristics of the two chassis in the Testing section.
EV Powertrain
Albeit out of our project scope, the following EV powertrain components have been selected to meet performance targets: EMRAX 228 motor, 150s5p battery pack (540 V nominal, 13.5 kWh), 16-tooth front sprocket with fixed 44-tooth rear sprocket (2.75:1 ratio), and 0.3 m rear wheel radius, targeting 250 km/h top speed. Detailed calculations are provided in Appendix B.
3.2 Fairing Concept Exploration
The concept evaluation of the structure and material of fairing can be seen in figure 3.2.1 .
In our early fairing concept explorations stage, we selected the full fairing. Upon further analysis, we narrowed it down to two technically viable directions within the sports series. A moodboard of our design inspirations can be seen in Appendix E.
-
Naked Fairing concept
Minimal upper body cover for simpler construction, lower part count and reduced visual bulk. Similar in philosophy to electric street motorcycles such as Zero SR/F (Zero Motorcycles, 2025) -
Full Fairing concept
Greater surface coverage around the chassis for higher aerodynamic performance, stronger visual continuity. Taking inspiration from the fairings of racing motorcycles such as MotoGP Aprilia (Aprilia, 2022)
In fact, this dual-variant approach is consistent with how established manufacturers position motorcycles for different rider demands. For example, Suzuki presents the GSX-8S as a naked streetfighter aimed at agility, urban use, and everyday riding; while describing the GSX-8R as a sport-oriented derivative with a full fairing, sporty riding position, and wind-tunnel-refined aerodynamic bodywork based on the common platform (Suzuki Cycles, 2023).
The fairing material concept selection narrowed down to fibreglass due to its excellent balance of strength and low weight, ease of manufacturing using low-cost tooling, aerodynamic smoothness, and superior repairability compared to plastics and carbon fibre. Moreover, it is affordable and supports iterative prototyping (Ferdaus, F. et al., 2021).
4. Prototypes
In this section, we will explore the different prototypes, for both chassis and fairing created through our development process.
4.1 Chassis Prototypes
Both CAD and physical prototypes were designed and built respectively, as seen in subsequent sub-sections.4.1.1 CAD Prototype
Using the Weighted Decision Matrix, we compared the 2 chassis design prototypes across 4 different criterias as seen in figure 4.1.1.1.
The bonded aluminium frame was selected due to its superior performance across critical design criteria. While both designs achieve excellent structural rigidity through trellis geometry, the bonded frame delivers substantial advantages in weight reduction and simplified manufacturability. The modest cost increase is acceptable given the performance gains, yielding a decisively higher weighted score that justifies progression to prototype fabrication.
4.1.2 Physical Prototype
The detailed workflow from Idea to Proof-of-Concept for our bonded aluminium chassis can be seen in Figure 4.1.2.1.
A side-by-side comparison of our CAD and physical prototype is seen in Figure 4.1.2.2
4.2 Fairing Prototypes
This section explores our iteration process for our two selected fairing concepts, Naked and Full, using Solidworks. A series of design requirements and aerodynamic considerations used can be seen in Figure 4.2.1.
4.2.1 Naked Fairing Concept
The design intent of the naked fairing model was to provide minimal bodywork primarily for covering and protecting essential components; while preserving a compact, lightweight, and exposed overall motorcycle form.
Two of the many design inspirations and four of the countless drafts created can be seen in Figure 4.2.1.1.
Throughout the design phase, there were many adjustments, changes and considerations. They are summarised into 3 iterations as seen in Figure 4.2.1.2.
4.2.2 Full Fairing Concept
The design intent of the full fairing model was to develop a bodywork configuration better suited for higher-speed, sport-oriented riding by managing airflow around the motorcycle more effectively than the minimal naked variant.
Two of the many design inspirations and four of the countless drafts created can be seen in Figure 4.2.2.1.
The fairing was initially developed using SolidWorks surfacing tools to create freeform bodywork aligned with the intended flow lines of the motorcycle. However, this approach proved too time-intensive for iterative development. A solid-based method was therefore adopted, where an initial packaging volume was created and progressively trimmed, refined, and shelled into the final fairing geometry. This provided a more efficient workflow and better control over the final shape.
Once the initial concept was developed, it was taken forward for preliminary CFD simulation. To improve realism, an open-source human CAD model based on a MotoGP riding posture (Appendix G) was incorporated into the study as seen in Figure 4.2.2.3. This also served as an ergonomic reference, since the absence of a conventional fuel tank in the electric aero model meant that the fairing had to help support a compact, aerodynamically efficient rider position in accordance with our aerodynamic shaping considerations in Figure 4.2.2.1. The results from this initial simulation were then used to guide subsequent refinements in an iterative CFD-driven design process toward a more aerodynamically optimised final design.
5. Testing & Analysis
5.1 Chassis - FEA
This section explores the testing and analysis of the bonded chassis using FEA on ANSYS Mechanical.
5.1.1 Load Cases
To evaluate the structural behaviour of the redesigned chassis under representative operating conditions, 3 standard static-equivalent load cases were selected: static loading, 1 g braking, and 3 g bump, as seen in Figure 5.1.1.1. These cases are widely used in early-stage motorcycle chassis assessment to approximate gravitational, longitudinal, and vertical impact loads in a controlled modelling environment (Cossalter, 2006).
5.1.2 FEA Methodology
The load cases for the bonded aluminium chassis analysis followed the same methodology as the original steel truss evaluation, ensuring consistency in the assessment approach. Each case was defined using a total vehicle mass of 300 kg, with gravitational acceleration of 9.81 m/s² applied as appropriate.
The FEA was originally conducted in SolidWorks Simulation, where load cases were defined with careful attention to boundary conditions, mesh convergence, and distributed mass representation. However, for the bonded aluminium chassis evaluation, the analysis was migrated to ANSYS Mechanical. This transition provided several advantages that improved both accuracy and efficiency.
In particular, ANSYS automatically handles distributed mass loading through its body force representation, eliminating the need for the manual distributed mass feature required in SolidWorks. This reduces setup complexity and potential sources of error when defining gravitational or inertial loads across the structure.
The geometry, material properties, mesh strategy, and boundary conditions were transferred consistently between the two platforms to maintain comparability. Mesh convergence studies confirmed that the ANSYS model achieved similar discretisation quality to the SolidWorks baseline, with element sizes refined in critical regions such as the bonded interfaces and high-stress mounts.
5.1.3 FEA - Bonded Aluminium vs Welded Steel Chassis
Bonded Aluminium Chassis FEA results
The design demonstrates excellent structural performance with all FOS > 3.0, even under the severe 3G bump condition. Peak stresses remain well below yield (extrusions are Al 6061 which has a yield strength of 260 MPa), confirming the design is conservative and suifigure for the target loads. Local concentrations at mounts and joints are predictable and manageable through extrusion geometry optimisation, without widespread yielding (Sabtu et al., 2024).
Welded Steel Chassis FEA results
The bonded aluminium chassis achieves superior structural efficiency compared to the previous welded steel chassis, evidenced by significantly lower peak stresses and much higher minimum FOS under identical loads. This validates the material and joining transition: aluminium extrusions provide better section efficiency for bending and torsion, while epoxy bonding avoids weld heat distortion and enables distributed load transfer superior to discrete welded nodes (Soetens & Hove, 2001).
5.1.4 FEA - Motor Loading
The final test case is the loading of the motor mount under the specified motor’s peak torque, which is 220 Nm, while the chassis is also under a static load of 1g.
The final FEA case evaluates the chassis under the motor’s peak torque of 220 Nm, applied simultaneously with the 1g static chassis load. This case is particularly important because it represents the most direct transfer of drivetrain torque into the frame through the motor mount, making it a critical check for local structural integrity and load-path continuity. The analysis shows a maximum von Mises stress of 33.9 MPa, which remains far below the aluminium yield strength of approximately 260 MPa, confirming that the chassis response is fully elastic under this combined loading condition.
The minimum factor of safety of 7.37 further indicates that the frame has ample reserve capacity to withstand peak motor loading without risk of yielding or local failure. The stress concentration is localised around the motor mount and adjacent support members, which is expected due to the applied torque and restraint conditions. Overall, this result demonstrates that the chassis can safely accommodate the motor’s maximum output while maintaining the structural performance established in the earlier static, braking, and bump load cases.
5.1.5 FEA - Conclusion
The FEA confirms the bonded aluminium chassis achieves excellent structural performance across all design load cases, including the motor mount evaluation under peak torque loading. Maximum von Mises stresses range from 25.7 MPa (static) to 77.0 MPa (3g bump) and 33.9 MPa (motor torque), with factors of safety from 3.37 to 10.09 which is substantially superior to the welded steel design’s peak stresses approaching 450 MPa and marginal FOS of 1.01 under equivalent conditions.
This comprehensive performance, combined with 40% mass reduction, validates the transition to a bonded aluminium design as it is both structurally efficient and aligned with e-bike performance targets.
5.2 CFD - Fairing
5.2.1 CFD mesh and computational domain
A summary of the CFD settings used consistently across all design iterations, Naked and Full Fairings alike, to investigate the influence of geometry changes under the same flow environment can be seen in Figure 5.2.1.1.
To balance accuracy and computational cost, a relatively coarse global mesh was first adopted, after which solution-adaptive mesh refinement was used to improve local resolution where required as seen in Figure 5.2.1.2.
Drag Equation
Post Processing Plots
In addition to the qualitative plots, quantitative force components in the global Z-direction were monitored during the refinement process as seen in Figure 5.2.1.5.
Total Force Z was used as the main indicator of the overall aerodynamic resistance acting along the flow direction. Normal Force Z was used to assess the contribution associated primarily with surface pressure effects, while Friction Force Z was used to track the contribution from viscous wall shear, or skin-friction drag. Monitoring these values together made it possible to distinguish whether a design iteration was improving performance mainly by reducing pressure-related drag, or by reducing friction-related drag along the surface.
5.2.2 CFD - Naked Fairing
This simulation was run so as to have a baseline, although this is a very idealised baseline as it was done with a human model in the aero position. It would prove more accurate when done with the human model in upright position which is what the naked fairing concept was designed for.
5.2.3 CFD - Full Fairing
A series of iterations using CFD to optimise the aerodynamic performance of Full Fairing concept were created as seen in Appendix G. The section explores the full fairing's final iteration in detail using Solidworks.
Final Iteration
Compared to the first iteration, the final design guides airflow more smoothly around the bike. Overall, the aerodynamic behaviour appears more refined and better controlled.
The final design achieved a reduction in total drag from 210.11 N to 172.3 N, corresponding to an improvement of about 18%, while the drag coefficient decreased from 0.772 to 0.678. The reduction was driven primarily by a decrease in pressure drag, indicating that the revised fairing geometry improved the overall aerodynamic shaping of the motorcycle-rider package.
Although the fairing records a higher Cd than values often reported for supersport motorcycles, its CdA is much more competitive, which means the overall bike-rider package still presents low aerodynamic resistance. Our concept achieved about 0.198 m² in the first iteration and 0.162 m² in the final iteration, while published benchmarks for tucked electric sport motorcycles are around 0.325 m² for a Ducati V4S and 0.347 m² for an Energica Ego+RS (Kirca and McGordon, 2024). This suggests that, despite being less shape-efficient in pure Cd terms, our fairing performs comparably to high-performance sports bike fairings once frontal area is taken into account through CdA.
6. Validation
6.1 Chassis Validation
To validate the FEA predictions, two physical loading tests were conducted on the fabricated chassis. These tests were designed to reproduce representative loading conditions that the motorcycle chassis would experience in service, namely seat loading from the rider and loading at the fork mount during braking. In both cases, the measured chassis displacements were compared against the corresponding FEA results to assess whether the numerical model was able to capture the structural response of the chassis with reasonable accuracy.
Load Test 1: Seat Bending
A summary of the seat bending load test can be seen in Figure 6.1.1.
The results from FEA and seat bending load test are tabulated in Figure 6.1.2.
Load Test 2: Braking Load
A summary of the seat bending load test can be seen in Figure 6.1.1.
The results from FEA and braking load test are tabulated in Figure 6.1.2.
Load Tests Conclusion
The comparison between our FEA and load test results are summarised in Figure 6.1.5.
6.2 Fairing Validation
The only way to validate our CFD results would be wind tunnel testing. However, there are no local facilities. As such, we decided to verify the design of our fairings through the manufacturing processe. A summary can be seen in Figure 6.2.1.
The rapid prototyping, using scaled down designs, enabled us to bring the design to life as seen in Figure 6.2.2. Enabling us to make improvements through close up inspections as well as gather feedback from fellow riders regarding the aesthetics.
7. Fulfilment of Deliverables
The intended deliverables of the project, together with their corresponding level of fulfilment, are presented in Figure 7.1.
7.1 Gantt Chart
Our project timeline is summarised in Figure 7.1.1.
8. Future Work
The potential gaps in the present study and the corresponding future work for improving the end product are outlined in Figure 8.1.
9. Potential Impact
This project demonstrates that bonded aluminium frame construction is a credible structural methodology for motorcycles and deserves greater consideration in future low-volume EV motorcycle development.
While the present work is limited to a student prototype, the structural validation carried out in this report shows that a bonded frame can provide a sound load-carrying response under realisitc loads. This is significant because bonded aluminium construction is already well established in commercially produced low-volume automotive platforms. European Aluminium identifies several relevant precedents, including the Lotus Elise and Evora, Aston Martin’s VH-platform vehicles, and the Morgan Aero 8, all of which employed aluminium chassis concepts based on adhesive bonding combined with mechanical fasteners.
In the Aston Martin DB9, for example, die-cast, extruded and stamped aluminium components were adhesively bonded and supplemented by self-piercing rivets, producing a structure that was 25% lighter than the preceding steel body shell while achieving more than double the torsional rigidity.(European Aluminium Association, 2013). Lotus’ Versatile Vehicle Architecture was intended for low and mid-volume applications using low capital investment manufacturing processes.
The impact of this project lies in showing that bonded aluminium structures should be regarded as a serious design pathway for future motorcycle platforms rather than as an unconventional alternative be it for electric motorcycles or ICE mototrcyles
References
-
(3M, 2018, Surface Preparation and Pretreatment for Structural Adhesives, https://multimedia.3m.com/mws/media/933332O/surface-prep-pretreatment-for-structural-adhesive-techbulletin.pdf)
(Atlas Copco, 2021, How to Select the Correct Rivet Size, https://www.atlascopco.com/en-sg/itba/expert-hub/articles/correct-rivet-size)
(Cossalter, V., Lot, R. and Massaro, M., 2014, Motorcycle Dynamics, https://doi.org/10.1002/9781118536391.ch1)
(European Aluminium Association, 2013, Applications - Car Body - Body Structures, https://european-aluminium.eu/wp-content/uploads/2022/11/1_aam_body-structures.pdf)
(Fintelman, D., Hemida, H., Sterling, M. and Li, F.-X., 2015, A Numerical Investigation of the Flow around a Motorbike When Subjected to Crosswinds, https://pure-oai.bham.ac.uk/ws/files/22607106/Fintelman_et_al_Numerical_Investigation_Engineering_Applications_2015.pdf)
(González-Arcos, B. and Gamez-Montero, P.J., 2023, Aerodynamic Study of MotoGP Motorcycle Flow Redirectors, https://www.mdpi.com/1996-1073/16/12/4793)
(Kirca, M.C. and McGordon, A., 2024, Effect of Rider Position on the Energy Consumption of an Electric Motorcycle, https://wrap.warwick.ac.uk/id/eprint/180779/1/WRAP-Effect-rider-position-energy-consumption-23.pdf)
(Kulkarni, C. and Kanthale, V.S., 2024, Design and Development of Chassis Frame Using Trellis Structure for an Electric Motorcycle, https://journal.esrgroups.org/jes/article/view/5858)
(Lava, P., Jones, E.M., Wittevrongel, L. and Pierron, F., 2020, Validation of Finite-Element Models Using Full-Field Experimental Data: Levelling Finite-Element Analysis Data through a Digital Image Correlation Engine, https://doi.org/10.1111/str.12350)
(Lee, W. and Zhang, C., 2018, Computational Consistency of the Material Models and Boundary Conditions for Finite Element Analyses on Cantilever Beams, https://doi.org/10.1177/1687814018780029)
(Martínez-Reategui, C.H., León-Japa, R.S. and Jurado, F., 2025, Optimized Fairing Development for Electric Motorcycle Using CFD Simulation and Finite Element Analysis (FEA), https://www.researchgate.net/publication/392979073_Optimized_Fairing_Development_for_Electric_Motorcycle_Using_CFD_Simulation_and_Finite_Element_Analysis_FEA)
(Nadikoppula, P. and Prasada Rao, M.Y., 2020, Static Analysis and Geometry Optimization of Rear Wheel Trailing Arm, https://www.irjet.net/archives/V7/i7/IRJET-V7I706.pdf)
(NASA Johnson Space Center, 2019, Process Specification for Adhesive Bonding (PRC-1001 Rev. G), https://www.nasa.gov/wp-content/uploads/2023/03/prc-1001-current.pdf)
(Sabtu, M.A., Admi, A.E., Mohamed Salleh, M., Osman, S.A. and Osman, S.A., 2024, Finite Element Analysis of Stress Distribution in AL6061 Chassis Structures under Varying Applied Loads, https://doi.org/10.30880/ijie.2024.16.02.027)
(Soetens, F. and van Hove, B.W.E.M., 2001, Aluminium Structural Design, Resistance of Connections, https://research.tue.nl/en/publications/aluminium-structural-design-resistance-of-connections)
(Suzuki Cycles, 2022, Suzuki Launches the All-New 2023 GSX-8S, https://suzukicycles.com/news/2022/11/08/17/36/suzuki-launches-the-all-new-2023-gsx-8s)
(Suzuki Cycles, 2023, Suzuki Takes on 2024 with the Stunning GSX-8R and Game-Changing GSX-S1000GX+, https://suzukicycles.com/news/2023/10/suzuki-takes-on-2024-with-the-stunning-gsx-8r-and-game-changing-gsx-s1000gx)
(WEST SYSTEM, n.d., Bonding and Clamping, https://www.westsystem.com/instruction/epoxy-basics/bonding-and-clamping/)
(WEST SYSTEM, 2015, User Manual & Product Guide, https://www.westsystem.com/app/uploads/2022/10/User-Manual-2015.pdf)
(Whitfield, K., 2012, Lotus Bonds with Aluminum, https://www.gardnerweb.com/articles/lotus-bonds-with-aluminum)
(Wiński, K. and Piechna, A., 2022, Comprehensive CFD Aerodynamic Simulation of a Sport Motorcycle, https://www.mdpi.com/1996-1073/15/16/5920)
Appendix
Appendix A: Donor Components Detailed Evaluation
Theoretical Chassis Design
Appendix B: EV Powertrain Detailed Calculations
Appendix C: FEA Beam, Shell, Mixed Mesh
Appendix D: Welding and Jigs
Appendix E: Fairings Concept Selection - Moodboard
Our moodboard which includes a diversity of motorbikes in the market to gather inspiration for our fairings designs. The red circles indicate our selected concepts.
Appendix F: Chassis Physical Prototype - Bonding Plan
Screenshot of the beginning of Bonding Plan which outlines the detailed choronological steps and desired sub-assemblies prior to full assembly.
Appendix G: CAD Model of rider's aerodynamic position in MotoGP
Appendix : Fairing - Full Fairing iteration using CFD
Appendix : Initial Chassis Analysis (Welded Trellis Steel )
Below summaries the work done for our previous chassis concept that is no longer pursued. Albeit, this research into the welded trellis steel chassis is pivotal to the project today.