JST Vol. 21 (1) Jan. 2013 - Pertanika Journal - Universiti Putra ...

Ahmad, D., Jamarei, O., Sulaiman, S., Fashina, A. B. and Akande, F. B.
Fig.5: A Comparison of the Motion Resistance Ratio of Pneumatic and Rigid Wheels on Tilled Surface
in terms of Towing Velocity: the Analytical Approach
Fig.6: A Comparison of the Motion Resistance Ratio of Pneumatic and Rigid Wheels on Wet Surface in
terms of Towing Velocity: The Analytical Approach
The motion resistance ratios, measured by the empirical and the semi-empirical methods,
also differed. The motion resistance ratios predicted from the Brixius equation were found to
be lower than those measured experimentally, and the main reason for this could be attributed
to the size of the tyre used to derive the model. Therefore, a multiplying factor was used to
derive the new motion resistance ratio models for the pneumatic and rigid bicycle wheels on
two deformable terrains. The factors are stated in Tables 7 and 8, and the models are presented
in Equations 16 to 19.
From Brixius’ (1987) equation for bias-ply tractor tyres, the motion resistance ratio is as
stated in Equation 5. Therefore, for the 660 mm pneumatic bicycle wheels at 414 kPa inflation
pressure, the motion resistance ratio was derived, as follows:
1
MRR ( Bicycle ) = 2.0254. (0.04 + )
B
2.0254
MRR ( Bicycle)
= 0.0810+
B
70 Pertanika J. Sci. & Technol. 21 (1): 283 - 298 (2013)
n
n
[16]