The Performance of Renewable Bicycle Chain Lubricants
University of Delaware
Natural or biobased lubricants are desirable on the market today due to their performance as a safe, ecological, and effective product. In this study we report on the friction and wear properties of commercial bicycle lubricants, natural base oils (e.g. canola, soy, etc.), and the effect of certain additives on these properties. A pin-on-disc tribometer was designed and assembled specifically for this study to measure the coefficient of friction and wear on a steel-on-steel contact for each lubricant sample. The design process and finalized schematics of the device are detailed. A correlation was also derived to relate the coefficient of friction of each lubricant to an associated power loss in a bicycle drivetrain. The commercial lubricants had a wide range of friction performance, with Slick Lube 100 giving the lowest COF of 0.042 ± 0.001 (power loss 7.80 ± 0.26 watts), and GT85 having the highest COF of 0.131 ± 0.003 (power loss 24.16 ± 0.51 watts). Wear tests resulted in a large disparity between the best and worst lubricants as well, with three samples effectively rejecting all wear during a one hour test, while the worst performer resulted in a wear track cross sectional area of 15.9 ± 3.3 μm2. The natural oils tested were excellent at reducing friction with an average COF of 0.040 ± 0.004, although the average wear performance of these oils proved to be worse than the commercial lubricants with an average area loss of 7.45 ± 1.7 μm2. However, it is shown that adding 5% or more by weight of an anti-wear additive can greatly improve this performance. Combining these results we explore possible correlations between friction, wear, viscosity, density, and individual lubricant components or additives.