This document describes the design of a shaft-driven bicycle as an alternative to chain-driven bicycles. A shaft-driven bicycle uses a drive shaft connected by spiral bevel gears to transmit power from the pedals to the rear wheel, replacing the chain. The objectives are to increase durability, reduce maintenance costs, improve efficiency, and reduce noise. Calculations are provided for the gearing and shaft design. Advantages include less jamming and protection of clothes, while disadvantages include increased weight. The conclusion is that shaft-driven designs can now match the efficiency of chain-driven bicycles.

1. JAIPUR NATIONAL UNIVERSITY
CHAINLESS BICYCLE
PROJECT STAGE – II

2. Project By:-
ALOK PRAKASH SINGH 8ME- 18
Guided By:- Submitted To:-
Asst. Prof. ARVIND KUMAR SINGH Mechanical Department
Mechanical Department JNU , Jaipur
JNU , Jaipur

3. ABSTRACT
 Shaft drives were introduced over a century ago, but were mostly
supplanted by chain driven bicycles due to the gear ranges possible with
sprockets and derailleur.
 Recently, due to advancements in internal gear technology, a small
number of modern shaft driven bicycles have been Introduced.
 Shaft driven bikes have a be where a conventional bike would have its
chain ring. This meshes with another bevel gear mounted on the drive
shaft.
 It is attractive in look compare with chain driven bicycle. It replaces the
traditional method.

4. INTROUCTON
 A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain
to transmit power from the pedals to the wheel arrangement displayed in
the figure.
 The shaft connected between the pair of spiral bevel gears.
 The main application of the spiral bevel gear is in a vehicle differential,
where the direction of drive from the drive shaft must be turned 90 degrees
to drive the wheels.
 The helical design produces less vibration and noise than convention
straight-cut or spur-cut gear with straight teeth.
 If bevel-wheels could be accurately and cheaply cut by machinery, it is
possible that gears of this description might supplant, to a great extent, the
chain-drive gear: but the fact that the teeth of the bevel-wheels cannot be
accurately milled is a serious obstacle to their practical success.

6.  Objectives of dynamic bicycle:-
1) Increase durability of bicycle with the help of shaft drive.
2) Reduce maintenance cost of bicycle.
3) Increase power transmission efficiency of the bicycle.
4) Making system more reliable.
5) Reduce noise pollution using shaft drive transmission system.

7. WORKING
 The shaft connected between the pair of spiral bevel gears.
 A drive shaft , propeller shaft is a mechanical component for transmitting
torque and rotation, usually used to connect other components of a drive
train that cannot be connected directly because of distance or the need to
allow for relative movement between them.
 Design a suitable drive shaft and replacement of chain drive to transmit
power from the pedal to the wheel without slip. It needs only a less
maintenance.

8.  Propeller shaft strength is more and also propeller shaft diameter is less
and it absorbs the shock. It turns into any angular position.
 The both end of the shaft are fitted with the bevel pinion, the bevel pinion
engaged with the crown and power is transmitted to the rear wheel through
the propeller shaft and gear.
 With our shaft drive bicycle, there is no grease on your hands or your
clothes , and no more chain and derailleur maintenance.

9. COMPONENTS

10. 1) Pedal
2) Wheel rim
3) Hub
4) Bevel gear
5) Shaft Drive

11. DESIGN
 The shaft rotates at a constant speed about its longitudinal axis.
 The shaft has a uniform, circular cross section.
 Acoustical fluid interactions are neglected, i.e., the shaft is assumed to be
acting in a vacuum.

12. CALCULATION
 Design calculation for gear: - Speed of gear (Ng), Velocity ratio, Teeth of
pinion (tp), Mass of rider (m), Length of the pedal lever (L)
Step 1) Maximum torque applied on bicycle
= (Mass of rider x g) x Length of the pedal lever [N-m]
Step 2) Calculate Rated power (PR) = 2πNT / 60 [kW]
Step 3) Select suitable teeth of pinion (tp)
V.R. = tg / tp
V.R. = Np / Ng

13. Step 4) Module (m) = D / t
D = m x t
Step 8)Vp = (π x Dp x NP / 60000)
Where, Pitch velocity (Vp) in m/sec
Design Calculation for Shaft: - Power (P) in W, Speed (N)
in rpm, Mass (m) in kg, Mass moment of inertia (I) in Kg-
m2, Polar movement of inertia (J) in m4.

14. APPLICATIONS
 It is used for racing purpose.
 Also used for off-road riding.
 For cycling.
 For public and bicycle rental purpose.

15. ADVANTAGE
 Less jamming.
 No chain bite.
 High efficiency than chain driven cycles.
 Greater clearance.
 It protects our clothes better.

16. DISADVANTAGE
 Heavier weight, usually 1-2 pounds.
 Gears can be used.
 Wheel removal can be complicated.

17. RESULT AND CONCLUSION
 In the beginning, chainless bikes were less efficient than standard bikes,
but the changes in technology allowed them to reach a level of efficiency
that made them practical for day by day use.
 The presented work was aimed to reduce the wastage of human power
(energy) on bicycle riding or any machine, which employs drive shafts; in
general it is achieved by using light weight drive shaft with bevel gears on
both sides designed on replacing chain transmission.
 The design of drive shaft is critical as it is subjected to combined loads.

18.  The designer has two options for designing the drive shaft whether to
select solid or hollow shaft.
 The solid shaft gives a maximum value of torque transmission but at same
time due to increase in weight of shaft.
 For a given weight, the hollow shaft is stronger because it has a bigger
diameter due to less weight & less bending moment .
 Hence we are trying to make the transmission smooth and easy by
applying the bevel gears and shaft attachment instead of chain, chain
sprocket.

19. REFERENCES
 R.S. Khurmi, J.K. Gupta “A Text Book of Machine Design”, S CHAND,
2005.
 B.D. Shiwalkar “Design Data for Machine Elements”, Denett, 2013.
 J. E. Shingley and C. R. Mischke, Standard Handbook of Machine Design,
McGraw - Hill Publication New York, Second Edition.
 Anup A. Bijagare, P.G. Mehar and V.N. Mujbaile “Design Optimization &
Analysis of Drive Shaft”, Vol. 2 (6), 2012, 210-215.

20.  Websites:-
1) Dynamic bicycles.com
2) www.engineeringtoolbox.com
3) https://www.e-book.com/bicycle-review.
4) https://www.mountainbicycles.com/powerbicycles.htm.
5) https://www.geartech.com/bewelgear-instruction.