So far in our series on chains vs belts, we've compared both types of transmissions in a test rig under lab conditions. All the data provided for chain drivetrains there was collected using light bearing oil. However, hardly anyone lubes up their drivetrains with bearing oil - especially if they're a performance conscious rider. For chain transmissions, the choice of lubrication has a considerable impact on the efficiency and longevity of the drivetrain - especially if you consider that lubrication types also differ in how easily they will pick up contaminants.
There's a lot of worthwhile data in this article, but if you're just here for the basics, you can jump to results.
In 2013 and 2014, Friction Facts and Velo News have collaborated on two chain lubricant efficiency tests. CeramicSpeed, who have obtained Friction Facts, have since expanded the list of tested lubricants.
As with their chain tests, the tests were carried out using a singlespeed test rig running at a steady power of 250 watts. Furthermore, top of the line Shimano, Campagnolo and SRAM chains were used for the tests.
Zero Friction Cycling seperates chain lubricants in four categories:
From a performance standpoint, nothing beats hotmelt waxes, with high end products in that segment (like Molten SpeedWax) sitting at 4.7 watts lost under the aforementioned test conditions. Furthermore, since it is completely dry, wax will attract less contaminants than wet lubes, meaning that the effects of harsh riding conditions on performance will be less severe. It will, however, quickly deteriorate in prolonged riding in wet conditions - more on that later.
Wax-based drip lubes share a lot of the advtantages and disadvantages of hotmelt wax. High end products like Squirt came in at 4.8 watts in Friction Facts' testing, and CeramicSpeed later expanded the results with a claimed 4 watts for their own UFO Drip. What sets these products apart from hotmelt waxes is primarily the arguably less involved application process and their comparatively reduced longevity.
The wet drip lube market encompasses a number of different sub-genres from teflon- or graphene-spiked lubes to old fashioned bearing oil. In Friction Facts' testing, top contenders like Rock'n'Roll Gold Chain Lube sit at around 5 watts expended, while simple bearing oil will set you back around 6.25 watts, being far from the worst option in the segment. Wet lubes are quick and easy to apply, don't need to dry out before use and will stay on longer in wet conditions - but they'll typically suck up a lot more dirt from the road even in dry conditions, creating a grimy paste that will quickly deteriorate performance and act like sandpaper to components.
For that reason, this type of lubrication is typically only recommended in circumstances where regular maintenance is not an option. It'll keep your drivetrain from running dry for longer, but as long as you stay within the service intervals of a wax based product, that will always perform better than a wet lube.
We've already mentioned how wax-based and wet lubes react differently to contamination. Fortunately, we don't need to just make a guess on the numbers, because once more, Friction Facts have taken to their lab to put this to the test in 2012.
The same test rig as described above was used to test a number of chains prior and after a slightly damp cyclocross race.
The three chains lubricated with wax-based UFO Drip showed an average efficiency loss of just 1.66 watts at a power of 250 watts (dropping from 6.66 to 8.33 watts in this case). The chains running light oils, on the other hand, averaged an efficiency loss of 4.33 watts (dropping from 6 to 10.33 watts).
A later test carried out by CeramicSpeed confirmed these results, where wax lubed chains decreased in efficiency by only 0-2 watts when subjected to very fine grit, while wet lubed chains suffered about twice that loss.
But what if what you're doing isn't just a short cyclocross race, but a long distance gravel or MTB route, where you can't just constantly stop and service your drivetrain?
Well, using a chain lubed in bearing oil, Friction Facts have tested that a prolonged ride in rainy conditions will cause chain efficiency to drop from 6 to around 13 watts at a power of 250 watts, 14 watts in wet mud, 18 watts in dried out mud and 20-30 watts in mudfest conditions.
While we don't have similar data for contaminated chains running on wax from Friction Facts, absoluteBlack's tests have shown that drivetrain friction using high end waxes doubles to around 10 watts within 120-140km of riding in the rain. Once the wax has been washed off completely and you're left with an unlubed chain, Friction Facts say you can expect the chain to cause 20-26 watts in efficiency losses.
A contaminated chain will also wear faster (and thus cause increased wear to other drivetrain components). This isn't just a cost issue, but also relevant in terms of performance. Friction Facts and Zero Friction Cycles have found that even once cleaned and relubed, chains beyond the 0.75% wear point would run around 2-4.5 watts slower than a new chain treated with the same lubricant.
To keep it simple: Going from a basic bearing oil to a wax-based lubricant will save you around 1.5 watts in dry conditions (and even more compared to even worse lubes).
What's more, it'll save you about twice that once some dirt and dampness are introduced to the equation. Since wax does not pick up dirt as easily, these savings will only increase as conditions get worse - as long as we're talking somewhat dry contamination. If things get extremely wet for prolonged periods of time, wax coatings can deteriorate completely, at which point the data suggests you might be even worse off than with a contaminated wet lube.
Keeping your chain well maintained pays off in any case, as a chain approaching 0.75% wear will run an additional 2-4.5 watts slower.