A mountain bike chain is prone to rust; even the mildest of watery conditions can bring about that familiar (to us) mucky brown appearance.
The steel used for the chain is, of course, prone to rust in even the mildest of watery conditions and brine is a much more aggressive agent of corrosion. Chain lube, besides providing a lubricating film between sliding surfaces, might be expected to coat them and thereby hinder the corrosion process. Which does a better job: wet or dry lube?
There are, of course, various wet and dry lubes of differing composition and, presumably, effectiveness. For the purposes of comparison we applied Muc-Off wet lube and Squirt dry lube to two chains prior to riding in especially challenging conditions. The former is the kind of thick, slow-flowing stuff that sticks to everything and might be expected to keep salt water at bay; the latter is a water-soluble dry lube with a fine reputation.
We ran two chains for a short period of time, one lubed with dry wax and the other with a wet lube. The results were eye-opening.
The rollers of the dry lube-treated chain have plenty of visible surface rust on an otherwise shiny surface where no lube remains, while the sideplates appear unaffected by corrosion. Contrastingly, the wet lube-treated chain has surface rust on the outside of the plates while the rollers appear to be oily and dirty if relatively rust-free.
Importantly, both chains have stiff links, those of the dry lubed chain being less obvious and cannot articulate to the same degree between sprocket and chainwheel. However, the dry-lubed chain ran much more smoothly afterwards with no “gritty” feel and even without the further application of lube soon freed off. The wet-lubed chain felt awful and needed a good clean before it would run smoothly.
The wax contained in the dry lube made a more effective barrier to corrosion than the oil of the wet lube. Although the sideplates of the wet lubed chain retained some oil coverage, they rusted slightly. Those of the dry-lubed chain did not.
This test also showed that the wet lube, as generally believed, attracted and held grit. It also failed to prevent rust attacking the inside surfaces of the chain, the stiff links indicating that they have begun to corrode despite the fact that the chain visibly retains a film of oil. The dry lube did not attract grit to anything like the same degree, meaning that a new application of lube is all that is needed to get it running nicely again.
So, for severe winter use a dry lube – and this one on particular – not only keeps the chain running more smoothly but staves off corrosion and, since it does not attract abrasive grit, should ensure a longer service life for chain and sprockets.