We have seen it. The pot of black grease, the dirty brush. And smearing, smearing… The result is a disgusting, dirty, bad lubricated chain. Lubrication serves as a limitation of friction. So where is the friction in a chain? Indeed, between the roller and the bushing. Think about 40 years ago. The mechanic dismounted the motorcycle chain for lubrication. He then boiled the chain in a casserole with hot oil. The heat opened the chain. The old oil dissolve and new oil could easy enter the small place between roll and bushing.
So our modern lubricant must:
- have a good penetration capacity
- have a low viscosity. To allow passage between the small openings (eventual pass the O-rings if present)
A good lubrication can keep the parts separate, even when a high force comes on it. The forces, between the roll and the bushing, come on one line to the friction surface. This creates a rather high pressure on the lubricant film. Therefor the lubricant must:
- have a viscosity high enough to support the cutting effect of the forces.
- have only a limited capability to coop with shear forces
The faster the motorbike goes, in all weather conditions, the faster the chain goes. Now, on the pinion and sprocket, the accelerations are huge. The chain changes direction completely while the lubricant wants to make a straight line. Don’t start laughing becaus now, our lubricant must also be:
- sticking to metals
- have a high water resistance.
How to choose a good chain lubricant?
- Go for a mineral oil.
- Choose a viscosity of 600 to 700 mPa.s @ 40°C.
- No solid lubricants like graphite, MoS2 or Teflon® (PTFE).
- As an extra, the oil should contain a “tackyfier”. This is a chemical additive. After some contact time with air this additive becomes a sticky, chewing gum-like substance.
- It is convenient to buy the chain lubricant in an aerosol. This way, the lubricant is already thin enough to penetrate between roll and bushing.
- When using it as bulk, dilute the oil a bit with gasoline before application.
When to apply? Think back at the beginning of times (40 years ago)….indeed, when the chain is warm, so after a ride. When coming home, spray or brush some lubricant on the chain. Arrange your jacket an helmet, enjoy a cup of coffee. Then wipe off the excess of lubricant with a clean cloth. Job done.
Recommended products: CRC High Speed Chain Oil, Texaco Cain Lube 680