This document outlines a project to design and develop an indigenous hybrid bicycle in Pakistan. It introduces the project team and provides background on the problems of air pollution and rising fuel costs that the bicycle aims to address. The proposed solution is described as a hybrid electric/manual bicycle that is locally developed and cost-effective. Design considerations around mechanical, electrical, and structural components are discussed, including calculating the required motor power, torque, and RPM based on the bicycle's expected weight and top speed. A 350W BLDC motor that meets the calculated specifications is selected.

1. Design and Development an Indigenous
Hybrid Bicycle
Candidates Information
• Syed Ali Moazzam (MEEN-19111039)
• Ahmad Rehan (MEEN-19111049)
• Muhammad Abdullah (MEEN-19111067)
• Hanzla Habib (MEEN-19111077)
• Muhammad Shahzaib (MEEN-19111008)
Supervisory Team
• Engr. Dr. Muhammad Sana Ullah Sahar
1

2. 1. Problem Statement
 World is facing a major problem of climate change
which is mainly due to the fossil fuel combustion.
• Conventional vehicles consume fuel and emit toxic
gases that has increasing air pollution. So this
Problem demands the use of alternate mode of
transportation.
• Air Pollution is a silent public health emergency in
Pakistan and kills over 128,000 people annually due
to air pollution related sickness1.
 Fuel prices have been soared since the start of post-
corona era. This has caused an excessive increase in
commuter’s/rider's expenses. Especially for students,
it is difficult to manage their travel expenses.
1: Toxic air kills over 128,000 Pakistanis every year , Dawn News(Today’s paper / July 24, 2023)
2: http://www.businesstoday.in-report-326884-2022-22
3: http://www.dawn.com/news/1565613
2
Fig 01: Top five air polluted countries in 20212.
Fig 02: Protest of Pakistanis over hike in petroleum prices3.

3. 2. Proposed Solution
 Manufacturing of a Hybrid Bicycle (Electric +
manual power) with qualities such as:
• Minimum operational cost
• Indigenously developed
• Easy to operate
• Environmental friendly
3
3. Project Significance
 The proposed solution has following significances:
• Cost-Effective transportation
• Promotes healthy lifestyle
• Design with a robust load capacity up to 80Kg.
Fig 03: Sustainable development goals (SDGs).

4. 4. Project Schematic
4
Fig 04: Schematic diagram.
t

5. 5. Design and Methodology
 Mechanical Design:
• Total Resistive Force calculations.
• Required BLDC motor power and
Torque calculation.
 Electrical Design:
• Battery Capacity calculation.
• Soldering of electronic components.
• Charging time Calculation
• Installation of electric components. 5
Fig 05: Pictures of different components required

6. 5.1 Total Resistive Force Calculation
6
 The Input parameters that will be used in the calculations are given in the
table below:
Symbol Parameter Value Comments
M Total mass 120kg • E-bicycle weight=25kg
• Rider + other miscellaneous
weight = 80+15 =95kg
V Velocity 30km/h Top Speed of the E-Bicycle
h Height 1.6m Distance from the lower part of
wheel to riders head
w Width 0.5m Distance from one side of handle bar
to other side
ρ Density of air 1.23Kg/𝑚3
Density of air medium (Kg/𝑚3
)
𝐴𝑓 Frontal area of bicycle 0.68𝑚2 𝐴𝑓 = 0.85× w× h
r Radius of the wheel 13inch Diameter of the wheel is 26’’
Table 1: Input parameters required for calculations.

7. 5.1 Total Resistive Force Calculation
7
To design an electric bicycle with a gross weight of 120kg (rider + bicycle) at a top
speed of 30 Km/h (8.33m/s) .This vehicle should overcome these resistance forces4:
Rolling Resistance
01
Aerodynamic Resistance
02
Gradient Resistance
03
𝐹𝑟𝑜𝑙𝑙𝑖𝑛𝑔 = 𝐶𝑟. m . a
𝐹𝑎𝑒𝑟𝑜𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 0.5(ρ. 𝐶𝐴. 𝐴𝑓. 𝑉2)
𝐹𝑔𝑟𝑎𝑑𝑖𝑒𝑛𝑡 = m . a . sinθ
Fig 06: Resistive forces acting on a bicycle5.
4: Design and Fabrication of an Electric Bike, A Karthi 1,N Afridhin2, D Aravind3, G Kamalesh4, K Rathish Kumar5/
5: http://skill-lync.com/student-projects/flow-over-bicycle-169
(1)
(2)
(3)

8. 5.1 Total Resistive Force Calculation
8
5.1.1. Rolling Resistance:
6: https://www.engineeringtoolbox.com/rolling-friction-resistance-d_1303.html
Calculation:
𝐹𝑟𝑜𝑙𝑙𝑖𝑛𝑔 = 𝐶𝑟. m . a
= (0.004 × 120 ×9.8)
𝑭𝒓𝒐𝒍𝒍𝒊𝒏𝒈 = 5.704N (let say 6N)
Rolling Resistance
Coefficient (𝐶𝑟): Type of Object:
0.001 - 0.002 railroad steel wheels on steel rails
0.001 bicycle tire on wooden track
0.002 - 0.005 low resistance tubeless tires
0.004 bicycle tire on asphalt road
0.005 dirty tram rails
0.006 - 0.01 truck tire on asphalt
0.02 car tires on tar or asphalt
0.02 car tires on gravel - rolled new
0.03 car tires on cobbles - large worn
0.04 - 0.08
car tire on solid sand, gravel loose
worn, soil medium hard
Table 2: Rolling resistance coefficients of vehicles6.
Input data:
𝐶𝑟 - Coefficient of rolling resistance
m - Mass of the vehicle (in kg)
a - Acceleration due to gravity (m/𝑠2)
Take:
𝐶𝑟 = 0.004
a = 9.8m/𝑠2
m = 120kg

9. 5.1 Total Resistive Force Calculation
9
5.1.2. Aerodynamic Resistance:
7: https://www.engineeringtoolbox.com/drag-coefficient-d_627.html
Calculation:
𝐹𝑎𝑒𝑟𝑜𝑑𝑦𝑛𝑎𝑚𝑖𝑐 = 0.5(ρ. 𝐶𝐴. 𝐴𝑓. 𝑉2
)
=0.5(1.23×0.9×0.68 × 8.332)
𝑭𝒂𝒆𝒓𝒐𝒅𝒚𝒏𝒂𝒎𝒊𝒄 = 29.46N (let say 30N)
Input data:
ρ = Density of air medium (Kg/𝑚3
)
𝐶𝐴= Coefficient of air resistance
𝐴𝑓= Frontal area of the bicycle
Take:
ρ = 1.23Kg/𝑚3
𝐶𝐴= 0.9
𝐴𝑓= 0.68𝑚2 (for our bicycles)
V = 30Km/h = 8.33m/s
Type of Object:
Drag Coefficient
(cA):
Airplane wing, normal position 0.05
Airplane wing, stalled 0.15
Modern car like a Tesla model 3 or model Y 0.23
Bicycle 0.9
Sports car, sloping rear 0.2 - 0.3
Common car like Opel Vectra (class C) 0.29
Sphere 0.5
Convertible, open top 0.6 - 0.7
Bus 0.6 - 0.8
Old Car like a T-ford 0.7 - 0.9
Cube 0.8
Bike - Racing 0.88
Table 3: Air drag coefficients of different vehicles7.

10. 5.1 Total Resistive Force Calculation
10
5.1.3. Gradient Resistance:
8: https://www.researchgate.net/figure/Resisting-forces-acting-on-a-bike-in-the-upward-motion-on-a-slope_fig_333800140
Calculation:
Input data:
𝐹𝑔𝑟𝑎𝑑𝑖𝑒𝑛𝑡 = m . a . sinθ
= (120 × 9.8 × sin 0°)
𝑭𝒈𝒓𝒂𝒅𝒊𝒆𝒏𝒕 = 0N
θ - Slope or gradient angle
m - Mass of the vehicle (in kg)
a - Acceleration due to gravity (m/𝑠2
)
Take:
θ = 0° (for flat surface)
a = 9.8m/𝑠2
m = 120kg
Fig 07: Gradient forces acting on a bicycle8.

11. 5.1 Total Resistive Force Calculation
11
Calculation :
To calculate the total resistive force acting on the bicycle we will
add all the
forces that we calculated before. So, the formula of total resistive
force becomes:
𝐹𝑡𝑜𝑡𝑎𝑙 = 𝐹𝑟𝑜𝑙𝑙𝑖𝑛𝑔 + 𝐹𝑎𝑒𝑟𝑜𝑑𝑦𝑛𝑎𝑚𝑖𝑐 + 𝐹𝑔𝑟𝑎𝑑𝑖𝑒𝑛𝑡
𝐹𝑡𝑜𝑡𝑎𝑙 = 6+ 30 + 0
𝐹𝑡𝑜𝑡𝑎𝑙 = 36 N
The bicycle has to overcome this 36N force to get propelled.

12. 5.2 Required Power Calculation
12
Calculation :
To calculate the power required to run this bicycle we will multiply
the total resistive force acting on the bicycle with the velocity of the
bicycle in m/s.
Given, V= 30Km/h =8.33m/s
F= 36N
Power = Total resistance force (N) × Velocity of the bicycle (m/s) 9
= 36 × 8.33
Power = 299.88 Watts
So, to drive a bicycle with a gross weight of 120kg
at a top speed of 30 Km/h (8.33 m/s) the required power is 300W.
9: DESIGN AND FABRICATION OF ELECTRIC BIKE-Shweta MateyDeep R Prajapati, Kunjan Shinde, Abhishek Mhaske, Aniket Prabhu

13. 5.3 Required RPM Calculation
13
Calculation :
9: DESIGN AND FABRICATION OF ELECTRIC BIKE-Shweta MateyDeep R Prajapati, Kunjan Shinde, Abhishek Mhaske, Aniket Prabhu
N = Velocity (m/min) / Linear distance travel by tire (m)9
N = 500/2.0735
N = 241.14 rpm
Input data:
Velocity = 30Km/h = 500 m/min
Radial distance = 2 π r
r = radius of the wheel (m) = 13’’ = 0.33m
Radial distance = 2 π (0.33)
Radial distance = 2.0735m

14. 5.3 Required Torque Calculation
14
Calculation :
10: DESIGN AND FABRICATION OF ELECTRIC BICYCLE ram bansal, avinash sharma, mohammed ali, pulkit shrivastav, vipul yadav,
sarthak mandloi and rachit dhanotia
Input data:
We Know that, p=2 π N T/ 6010
so, T = P × 60 /2π N
T = 300 (60) / 2π (241.14)
T = 11.88Nm (let say 12Nm)
P = Required power required (W) = 300 W
N = RPM required (rpm) = 241.14 rpm
T = Required Torque (Nm)

15. 5.4 Selection Of Motor
15
Fig 08: Motor and wheel Assembly.
After performing all the calculations for motor
we have selected EMF BL-10-36-350-320
BLDC motor.
 Specifications of EMF BL-10-36-350-320
BLDC hub Motor11:
• Rated Power: 350W
• Rated Torque: 11Nm
• Peak Torque: 51Nm
• Operating Voltage: 36V
• Rated Current: 8A
• Rated RPM: 320rm
11: http://www.emf-i.com/download/EMF-BL-10-36-350-320/