Lube FAQ

Lube FAQ

The maintenance of a bike drivetrain is important for riders who are aiming for high performance standards.  This is a collection of technical information on bike drivetrain which should answer some frequently asked questions and assist in searching for the perfect lube.

The topic of chain lubrication can become extremely emotive for one simple reason - every ride is different.  What works for one rider, drivetrain, bike and journey may not work as effectively next ride, or for a different rider, or on a diffferent bike.  Most cyclists have a natural tendency to help other cyclists, so when someone is lucky enough to find a lubricant that works well for them, they feel completely justified in sharing this secret with others. It is a combination of factors which means that there will always be a lot of discussion on the best lubricant.

What causes drivetrain noise?

Excessive drivetrain noise can be caused by several things e.g. noisy jockey wheels, misaligned derailleur, poor meshing of chain and sprockets, grit adhesion on outside of chain during wet rides etc and cannot always "blame" the noise on the lubricant.  

To check if lube levels are sufficient squeeze the chain firmly betwen thumb and forefinger.  If lube can be squeezed out of the chain between rollers and plates and leaves a coating residue on the finger/thumb then lube levels should be sufficient. A top-up lube is advised if no significant lube can be squeezed off the chain in this way. Suggested residual levels of well lubed chains are indicated below.
PANO LUBE  

If there is no lube inside a chain the characteristic and frustrating grinding noise comes from the metal-on-metal contact surfaces inside the chain. This is a noise which no rider wants to accompany them on their ride!!

What is difference between wet and dry lubes?

In very simple terms, a wet lubricant remains a fluid which can flow around inside & outside the chain to give long-lasting lubrication on inside and outside surfaces.  A dry lubricant forms a film and feels "dry" to touch. This video is a good demonstration comparing wet and dry chain lubricants.  


It is intutive that a wet lube will be attractive to dust & grime and under riding conditions forms a dark grit paste that can cause noise and become messy for the whole drivetrain including jockey wheels, sprockets and chainrings.  In some riding conditions with low dust (e.g. very cold snow and ice) a wet lube is perfect with no buildup of grime.  However, most riders will encounter dust and a dry lube is preferred to limit the buildup.  Most riders prefer a dry lube.  The complication is that there is a direct relationship between lube durability and fluidity = a wet lube will last longer than a dry lube. 

DIRT ATTRACTION 
The wet lube moves within the pins, bushings and rollers and this very feature which makes it tenaciously stick to the metal components, is the feature which attracts the dirt. A dry lube creates a film which does not behave like a fluid.  It moves more like a paste and squeezes off the metal surfaces.  It also needs to be fully pre-loaded into the chain pin/bushing cavity. When using a dry lube the chain should be cleaned before applying so that the lube can penetrate into the cavities of the chain.  Most dry lubes incorporate a dual function clean/lube where the carrier solvent can flush out the chain and clean any buildup in the small "lube delivery" gaps between the bushings.  If these gaps are too small or clogged then lube will not penetrate onto the pin surface where most contact wear occurs.  If using viscous water-based wax lubes, or "molten paraffin" then the chain must be cleaned well before lube is applied.  


Explain the parts in a bike chain?

The chain on almost every bike now is "bushingless".  The original invention by Guy Dupoyet was patented in 1978 by Compagnie des Transmissions Mecaniques Sedis and the original patent ishere.

A good quality bushingless chain can last up to 10,000km with good lubrication.  They shift well and can be made light and narrow.  This development is arguably the biggest technical improvement which has happened to a bike over the last 30 years.  The parts of a bicycle chainare: outer plate, roller, pin, inner plate.  The load transfer is from the outer plate via the fixed pin pulling and rotating on the inner link plate bushing surfaces.  Load transfer from inner plate onto outer plate is via the inner bushing surface pulling and rotating on pin. A chain does not elongate along pin-pin distance of outer plate which always remains 12.7mm. Wear is on pin and bushing surfaces along inner plates where there is movement and load.

The components of a chain and chain wear are demonstrated in this video.


Does my new chain have a lube coating?

The coating which chain manufacturers use is applied to protect the chain in transit so that it does not corrode before use. The chain coating can be removed and the coating isolated and tested.  This video provides more detail of the coatings on SRAm and Shimano chains.



The efficiencies of new chains coated with factory lube coating have been tested by Jason Smith at Friction Facts using his power efficiency apparatus.  The stickier SRAM factory coating (10.0W) was found to have much higher friction straight out of the box than the Shimano coating (7.2W).  Thoroughly cleaning the new chains and reloading both with the same low viscosity mineral oil (wet) lube resulted in a slight drop in friction of the Shimano (6.9 to 6.6W) and a significant reduction in friction of SRAM chain (10.0 to 6.9W) clearly demonstrating how the tacky nature of the protective factory coating can impact on lubrication efficiency.
Equipment

 

Where is friction loss in a chain?

It is well understood that the majority of friction occurs in areas of high load and tension, in particular on the disengagement of the chain from the rear sprocket and then upon engagement at the front chainring. Furthermore, a larger articulation angle in the link causes higher friction and load. Smaller sprockets create higher friction and wear than larger ones. The diagram below outlines the different zones of movement and friction in a chain upon disengagement from an 11T rear sprocket tooth under load.

PANO small
A close up of this movement is shown in the video and the link articulation angle can be clearly seen on entry into the sprocket from the derailleur and upon exit.  Also note there are only 6 teeth contacting the chain at any time. Chain tension in an explosive 1500W burst of power is the equivalent of lifting 150kg a height of 1m in 1 second. In this case the tension on the chain and consequently transferred into the sprocket tooth at disengagement is very high, around 1500N which is high enough to cause metal deformation on the very small surface contact points of the pins and bushing.