This document summarizes research on optimizing operating power in bicycles using non-circular chain rings. It reviews several studies that have investigated different types of non-circular chain rings, including Q-rings, oval rings, and ovate rings, and their effects on pedaling kinematics, forces, and efficiency. One study used musculoskeletal modeling and found a non-circular chain ring shape that could increase average crank power by 2.9% compared to a circular chain ring. However, another study found that a new proposed non-circular chain ring design did not improve performance over a standard circular chain ring during high-intensity cycling.

1. International Journal of Research in Advent Technology, Vol.2, No.8, August 2014
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Optimization of Operating Power in the Bicycle using
Non-circular Chain Ring: Review
Prof. Mahesh S. Gorde 1
, Prof. Vishal V.Bhoyar2
, Prof. Satish B. Chawale3 Prof.Nishant D.Jogi4
Department of Mechanical Engineering, Jawaharlal Darda College of Engineering & tech.,
Yavatmal 1,2,3,4
gordemahesh7@rediffmail.com1, vishalsadguru@gmail.com2, satishchawale@gmail.com3
ngjogi@gmail.com4
Abstract: This paper attempts to provide the reader with a complete picture of recent development in the field of
optimization of operating power in the bicycle using Non-circular chain ring through a systematic literature
review. Since many countries, the bicycle has been introduced as part of the urban transportation system to extend
the accessibility of public transportation systems to final destinations. Usage of bicycles can help reduce air
pollution produced by fuel combustions and has many advantages compared to other transportation mode . These
facts have caused some communities to promote “Bike to Work” movements. Many research are carried out to
optimized operating power & increased operating efficiency of the bicycle using Non-circular chain ring.
Keywords: Bicycle, circular chainring , Non-circular chainring.
1. INTRODUCTION
The bicycle rider undergo heavy physical stress during
riding of bicycle. In India, bicycles are one of the most
important means of transportation. In the past years, the
changes that took place in the design of the bicycle have
not been very prominent. Several studies have been
carried out on use of eccentric & non-circular chain rings
in bicycle. Many researcher focused on improvement of
operating efficiency of bicycle using various type of chain
rings viz. Q-ring, O symmetric-Harmonic ring, Ovum
ring, Ogival ring, LM- super ring , Polchlopek oval ring
etc. Most of the studies shows the comparison of any one
type of non-circular chain ring with circular chain ring. A
literature review has been done on recent developments in
the areas of pedal operated bicycle.
Photographic view of various Non-circular chain
rings as shown in table.
O.symetric-
Harmonic
Q-Ring
(Rotor)
Polchlopek
oval
Ovum Ogival LM-Super
2. LITERATURE REVIEW
Carpes F.P. investigated the three-dimensional
(3-D) pedaling kinematics using a noncircular chain ring
system and a conventional system. The purpose of this
study was to investigate the effects of a noncircular chain
ring system design for cycling on the 3-D pedaling
kinematics of cyclists new to the system. Statistical
significant differences in pedaling kinematics were found
between the noncircular chain ring system evaluated and a
conventional crank system. As this investigation was
carried out on indoor wind-load cycling simulator
(Cateye CS 1000, Cateye Co., Japan) the various factor in
actual road condition are not consider in it.
Gerda S. investigated kinetics and kinematics
between circular and two different shapes of non-circular
chain rings. With the help 14 cyclists pedaling on 90 rpm,
two-minutes cycling trials using three chain rings ranging
from circular to ovality of 1.10 and 1.215 has been carried
out . A significant increase of tangential pedal forces and
hip joint moments were observed. Non-circular chain
rings do not evidently seem to enhance performance, but
facilitated conditions for muscle activation as well as a
reduction of knee joint moments can occur.
Rankin J.W developed musculoskeletal model by
using SIMM software .As most studies have sought to
improve cycling performance by altering various aspects
of the pedaling motion using novel crank–pedal
mechanisms and non-circular chain rings. However, most
designs have been based on empirical data and very few
have provided significant improvements in cycling
performance. In this research work author developed
musculoskeletal model by using SIMM software. Forward
dynamic simulation and dynamic optimization were used

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to determined the muscle excitation pattern and chain ring
shape that maximized average crank power over the
pedaling rate 60,70,90 rpm. Power during isokinetic
pedaling conditions. The optimization identified a
consistent non-circular chainring shape at pedaling rates
of 60, 90 and 120 rpm with an average eccentricity of
1.29 that increased crank power by an average of 2.9%
compared to a conventional circular chainring.
The purpose of this study was to use a theoretical
framework that included a detailed musculoskeletal model
driven by individual muscle actuators, forward dynamic
simulations and design optimization to determine if
cycling performance (i.e., maximal power output) could
be improved by optimizing the chainring shape to
maximize average crank.
Neptune R.R investigated whether
neuromuscular quantities were associated with preferred
pedaling rate selection during submaximal steady-state
cycling from a theoretical perspective using a
musculoskeletal model with an optimal control analysis.
Specific neuromuscular quantities of interest were the
individual muscle activation, force, stress and endurance.
To achieve this objective, a forward dynamic model of
cycling and optimization framework were used to
simulate pedaling at three different rates of 75, 90 and
105 rpm at 265 W. The pedaling simulations were
produced by optimizing the individual muscle excitation
timing and magnitude to reproduce experimentally
collected data. The results from these pedaling
simulations indicated that all neuromuscular quantities
were minimized at 90 rpm when summed across muscles.
In the context of endurance cycling, these results suggest
that minimizing neuromuscular fatigue is an important
mechanism in pedaling rate selection. A second objective
was to determine whether any of these quantities could be
used to predict the preferred pedaling rate. By using the
quantities with the strongest quadratic trends as the
performance criterion to be minimized in an optimal
control analysis, these quantities were analyzed to assess
whether they could be further minimized at 90 rpm and
produce normal pedaling mechanics. The results showed
that both the integrated muscle activation and average
endurance summed across all muscles could be further
minimized at 90 rpm indicating that these . quantities
cannot be used individually to predict preferred pedaling
rates
Belen L. proposed a new PC prototype chain
ring (non-circular) and theoretically it was found that it is
more efficient than conventional circular chain ring .The
main feature of the PC is that crank-arm alignment and
lever-arm length change as a function of the crank angle
during the pedaling cycle. The PC presents two features
theorized to effect cycling performance, first one out of
line of pedal cranks resulting in an decrease in the dead
points, and second a change in crank arm length inducing
a torque different from that of conventional chain rings
during the down- and up-stroke of the pedaling cycle. To
investigate this theory, author examined eight male
cyclists who performed a 1-km ‘‘all-out’’ cycling test in
the following order: SC, PC, and SC. Performance was
measured as the time (s) to complete the 1-km test.
Mechanical variables included torque (N m_1), crank
velocity (rads_1), and power output (W). They performed
statistical analysis using a two-way ANOVA for repeated
measurements and Newman–Keuls post hoc assessment.
And the results shows that performance was similar for
SC 69.41 ± 6.69 s) and PC (73.33 ± 4.58 s). Torque, crank
velocity, and power output were also similar throughout
(P > 0.05). Finally they conclude that despite the
theoretically benefits proposed by the inventors the new
PC investigated in their study failed to improve cycling
performance or mechanical variables during a
supramaximal test when compared with SC.
Rasmussen J., described the optimization of a
bicycle crank mechanism equipped with springs. The
purpose of the springs is to cause an even torque
development over the crank cycle by elimination of the
so-called dead centers of the cycle. The field of virtual
prototyping as manifested by technologies such as
Computer-Aided Design, Finite Element Methods, and
Computational Fluid Dynamics has had a very significant
impact on modern product design. Hardly any advanced
product today is designed without the use of some sort of
computer simulation, and virtually any technical property
of products can be analyzed, including strength, vibration,
heat conduction, magnetism, flow, acoustics, and light
reflection just to mention a few. However, one prominent
property of products has been missing from the range of
analysis facilities until recently: The mechanical influence
of the product on the human body has not been in the
range of analysis. This property also often called
ergonomics does not seem like a very important addition
at first glance.
Modak J.P., suggested machine system used
human energy achieved by pedalling and stores this
energy in a flywheel at an energy-input rate convenient to
the pedaller. After storing the maximum possible energy
in the flywheel (pedaling time could be 1-2 minutes) the
same can be made available for the actuation of any
process unit by making available the energy stored in the
flywheel through a suitable clutch and torque-amplification
if needed. Thus the flywheel will decelerate
depending on the actual resisting torque offered by the
process. It implies that the pedaller does not pedal while
the flywheel is supplying energy to the process-unit.
[8] Spicer J.B.,performed experimental study on the
efficiency of bicycle chain drives under a variety of
operating conditions and to explore the factors that govern
chain drive efficiency. The efficiencies of bicycle chain
drives was investigated both experimentally and

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theoretically to provide quantitative measurements of
chain drive efficiency and to present models for power
loss. These models for drive losses have been used to
interpret experimental results. Assuming that the losses in
the chain drive result from friction between contacting
components that execute motion relative to one another,
there are three significant sources for loss as follows: [1]
Inner link bushing and chain pin, [2] Chain line offset, [3]
Sprocket tooth, link roller and inner link bushing. Tests of
efficiency for the derailleur-type chain drive indicate that
the overall efficiencies for the transfer of power from the
front drive sprocket to the rear sprocket range from 80.9%
to 98.6%. Primary factors affecting the efficiency include
the sizes of the sprockets in the drive and the tension in
the chain. Experimentally it was found that larger
sprockets provide more efficient transfer of power while
smaller sprockets proved to be less efficient. In frictional
loss models a 2–5% loss difference was measured
between the 52–11 and the 52–21 sprocket combinations
depending on the drive operating conditions..
Zikiuddin K.S.,discussed the importance of
human power from the earliest times to the present and its
future scope. As the use of natural fuel is increased due to
industrial development, it’s storage going to end. We need
to come with alternate source of energy, i.e non
conventional energy. Human power credits its importance
in search of an alternative source of energy as it fulfills
the requirement of renewable source of energy. More
effective use of human power can do by using
mechanisms. The technology used to transmit human
power to the working unit is termed as human powered
machine. The appropriate and most effective technology
to use human power efficiently is bicycle technology and
more scientific effort is needed to increase the efficiency
of bicycle.
Hue O. compared the circular & non circular
(eccentric) chainring operating performance
physiologically & biomechanically with 1.05 & 1.38
eccentricity of chainring at outdoor 1- km laboratory test.
The eccentrically design chainring was made of two crank
arms sliding into each other, with the inside arm fixed on
the center of the arm of a circuler chainring and outside
arm sliding along the inside and revolving around an
elliptical cam.In this design increase crank arm length at
the downstroke and decreases it during the upstroke, thus
increasing and decreasing the torque. Author conclude
that eccentric chainring significantly improved the cycling
performance during all-out 1-km test. But all variable
parameters were not considered in this study.
A.R.Lende ,developed model & simulation of
human powered for field data in the course of artificial
neural network and also try to developed artificial
intelligence. The experimental Independent variables
were reduced by evaluating dimensionless pi terms by
Buckingham pi theorem and a mathematical equation was
generated by traditional method to predict them
experimental findings. The equation is as shown. ω T =
1.288 ( I/RT2)-0.46 (ME)-0.87 (G)0.40. This research is
contributes in development of optimal model through
artificial neural network which enables to predict
experimental results accurately for seen and unseen data.
Ohara C.R. described the effects of chainring
type (circular vs. the non- circular Rotor Q-Ring) on
performance during a 1km time trial and physiological
responses over a six week period. Eight competitive male
cyclists and triathletes were pre-tested using the original
circular chainring. Graded submaximal exercise tests
were followed by the 1km time trial with subjects using
their own racing bicycle. The circular chainrings were
then removed and replaced with Rotor Q-Rings during the
intervention period. Subjects trained and raced with this
alteration to their bicycles and repeated the submaximal
and 1km performance tests for the next four weeks. Post-testing
occurred with the original circular chainrings for
the final week of testing. Oxygen consumption, carbon
dioxide output, heart rate, ventilation, respiratory
exchange ratio, and perceived exertion were continuously
measured during the submaximal tests. Blood lactate
concentration was measured during the last 30 s of each
three minute stage. The main findings were 1) Significant
increases in performance in the 1km time trial with Rotor
Q-Rings compared to circular chainrings. Subjects
completed the time trial on average 1.6 seconds faster ,
increased average speed approximately 0.7 kph , and
increased average power approximately 26 watts . 2)
During submaximal testing, oxygen consumption and
heart rate were significantly lower with Rotor Q-Rings
compared to circular chainrings.
3. CONCLUSION
Many research are carried out to optimized
operating power & increased operating efficiency of the
bicycle using Non-circular chain ring. This paper gives
overall review of Optimization of operating power in the
Bicycle using Non-circular chain ring. But still non-circular
chain ring is not in use because of some practical
problem so this area having a lot of scope for research.
REFERANCES
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and kinetics in cycling with circular and non-circular
chainring ”, 30 th Annual conference of Biomechanics
in sports – Melbourne 2012.
[3] Rankin J.W.,”A theoretical analysis of an optimal
chainring shape to maximize crank power during

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E-ISSN: 2321-9637
47
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