Tech Talk
Welcome to Tech Talk. Short and to the point, our monthly articles aim to keep the average cyclist informed on how to keep their bikes running smoothly, longer.
Oil your chain + keep it moving = longer chain life
We get asked on a very regular basis “what should I use to lubricate my chain?” There are many specialty lube’s available such as dry lube, Teflon lube, wax, graphite, light oil, heavy oil etc. Which is best?
I am going to digress but bear with me.
Bike chains are a very basic but also a very misunderstood piece of equipment. For example a chain does not go round. By this I mean that a circle is a series of straight lines joined together. These straight lines have no length to speak of, they are just dots. In the case of a bike chain these lines are half an inch long so technically it does not run round in a true circle it is subject to the polygonal effect. Because of this action chains don’t like small sprockets.
The load ratings on chains are generally calculated at electric motor speed of 1440rpm. From 0 to about 2000rpm the load capacity of a chain increases as the speed increases. The load capacity of ½” chain is not very high at a cycling cadence of 70-120rpm, its actually working hard. This can cause chain stretch on a poorly lubricated chain.
What we term chain stretch is actually wear. The steel on a chain does not stretch it is the wear on the pins and rollers that give the lengthening effect.
The fewer the teeth on a sprocket, the greater the degree of articulation, the lower the power factor and the higher the wear factor. A 17T sprocket will transmit 90% of the chains rated power at any given speed where an 11T sprocket will only transmit 30% of the rated power.
What does all this mean?
It is important to oil your chain. In my past life as a transmission engineer my customers and I tried all sorts of chain lube. The only lube that ever worked continually and successfully, to give a satisfactory wear index, was good old oil.
Do not use thin oil; the low speed and high load on a bike chain will cause it to squeeze out. We use Ice Toolz Teflon lube. This lube is heavy enough to cope with the loads on a bike chain, and it can be flushed out when the chain is cleaned. Put a drop of oil “across” each roller so that it will penetrate between the chain pins, rollers and side plates were it is required. If you are worried about your chain looking dirty using these lubes (they do pick up dirt) you will just have to put up with replacing your chain and sprockets regularly.
Clean and lube your chain regularly keep your cadence up and stay on bigger rear sprockets (the two go together) and your chain/sprockets will last longer.