Ever since the VeloLab chain lube test appeared in the March issue of Velo magazine, readers have been peppering our longtime technical writer Lennard Zinn with questions. Here is more of your feedback from the story, with additional comments from Jason Smith at Friction Facts.
Wax has its benefits
Related to your recent chain wax lube article, here’s a study that may help explain why paraffin works – it does a good job taking up space in between all the chain’s parts. One surprising finding – the lube doesn’t have much effect on a chain’s efficiency. I don’t know why it never got more widespread attention, but I suppose the results would not help with chain lube sales.
Those indeed seem to be surprising results. The cog size increasing chain efficiency is legit, though. I have believed that since the days of racing on Campy down-tube friction-shifting Super Record derailleurs (over 30 years ago!), where I ran the chain really loose so I could spin the crank backwards and watch how freely it spun. I could see the difference based on cog size and thought I could feel how much more efficient it was in a larger chainring and larger cog than riding similar gear inches using a smaller cog and chainring.
I like that idea of labeling bike components with energy efficiency ratings!
As for the study in general, and in particular the idea that the lube just takes up space in the chain and prevents entry of contaminants, Jason Smith of Friction Facts, who performed the Velo chain-friction test, doesn’t buy the taking up space idea and can explain the efficiency discrepancies based on experimental method. Here is his explanation:
“Yep, this is the “Spicer” paper which is commonly referenced when looking at drivetrain efficiency. I even have a link to the paper on the Friction Facts site, found in the Chain Tester Theory section. Here’s the complete paper.
I have a few issues with Spicer’s equipment and procedure, which I dive into below. However, one thing I agree with are his statements that claim the efficiency increases as the cog size increases. The 98.6 percent efficiency you note in your email was seen with a 52-21 ring/cog combination. The testing Friction Facts performed used a 53-11 combination. If you look at Spicer’s paper at the 52-11 combo, Spicer claims a 95.8 percent efficiency, which is 10.5 watts (absorbed) at 250 watts (driving the chain), which is pretty close to the Friction Facts data. Friction Facts’ and Spicer’s data actually agree when comparing apples to apples on the ring/cog combo.
A few issues exist with the experiment. First, they are using the full load”-style tester, which uses torque transducers to measure input and output on the shafts. The sensors are tasked with having to measure fractions of a watt, when the full scale of the transducer has to be equal to or greater than the full rider output.
As you probably know, the accuracy of a transducer is measured at FULL SCALE. An analogy is trying to discern the weight of a grain of sand when added to a pile of sand, on a bathroom scale. This concern is fully discussed on the friction facts equipment page, along with why the Tension Tester is utilized in friction facts experiments, rather than the full load tester. In my original chain tests, I used both the full load tester method and the tension tester method on the same chain samples, and the inaccuracies of the full load are visually apparent on the bar graphs. Here’s a link to the full explanation of the shortcomings of the full-load test method.
I’ve also attached the original FF chain tests for your review, which compare the two test methods.
Now to get to Spicer’s claim that lube doesn’t matter. This is a very bold statement, especially when just after the lube test copy, he states in his report, “The most notable aspect of these efﬁciency data is that all values are approximately 1.5 to 2 percent lower than the corresponding values in Tables 2 and 3. This drop in efﬁciency could have resulted from wear in the chain.” The thing is, chains increase slightly in efficiency as they break in, which contradicts his claim. Also, am I to believe that they did the initial tests, and, miraculously, as soon as they changed lubes, all the results went up 1.5- 2.0 percent immediately? I’m not buying it.
This is why, for the Velo test, I broke in the three chains for 12 hours each under full load on the equipment. This minimized the chance of the results being affected by chain wear.
Interesting comment on the paraffin taking up space. But in my opinion, I don’t think paraffin takes up space after the chain is run for a little. Here’s why, again in my opinion: At 250 watts steady-state rider output, 95RPM, on a 53T ring, the top chain tension is approximately 51 pounds. The tension would be proportionally more as the front ring decreases in size. But I’ll use a 53 ring for a best-case scenario. Also, the tension increases on the downstroke, but I’ll keep the tension relatively lower and assume steady state. Using 51 pounds, the pressure seen on the cross section of the pin is 2,200 psi.
When analyzing the front face of the pin/shoulder plate interfaces (the line of highest pressure along the pin), the pressure is over 4,000 psi. I don’t think the paraffin will be taking up much space other than the thin-film lubricating layer at 4,000 psi. Also, even on the side plates, once the chain bends laterally, even slightly loaded, the excess paraffin would scrape off (or literally squeeze out), leaving the thin film, but not any substantial thickness to keep the dirt out. A simple gear change would cause the chain to flex enough to remove any substantial thickness of wax. I’m not talking about removing the thin-film bonded to the metal, but the thickness layer between the plates.
How’s that for a thorough explanation?
Wax or kerosene?
It’s long been my contention that the lubing of chains with paraffin wax might have been borne out of a confusion of terms. Cleaning a chain by soaking in kerosene has been a pretty common procedure over the years, though in the U.K. the translation would be to soak it in “paraffin.” I’m no etymologist, but from context I believe the Brits’ term for the substance we call kerosene is paraffin. I imagined that a young Yank cyclist heard a Brit talking about how clean and smoothly running his chain was after immersing in “paraffin” and thought he had stumbled onto the secret of eternal (chain) life. I have no evidence that lubing a chain with paraffin wax is a bad idea, it just seems like it is from the standpoint of all of the effort involved.
By the way, did the lube tester also test no lube at all? Perhaps a freshly cleaned, un-lubed chain has even less resistance, or maybe a constant drip of water from a water bottle to keep the chain lubed with very low viscosity.
Well, that’s an interesting etymological theory! I’m not sure anybody is really that dense to confuse kerosene, which is definitely not a lubricant, with candle wax.
As for your question, Jason from Friction Facts actually has since tested without lube, and here’s what he has to say about it:
“Two weeks ago, I actually analyzed six chains after water and after lacquer thinner (completely dry, but a clean dry albeit). This is a continuation of the “Dirty Chain” test (attached).
I started with the six now-cleaned and lubed chains from the Dirty Chain test.
Part 1 was an Ultrasonic clean with pure water (no dirt or grime). Allow to dry and test dry.
Part 2 was an Ultrasonic clean with Lacquer Thinner. Allow to dry and test dry.
The average chain friction after pure water was 6.67 watts. The average chain friction after Lacquer thinner, of the same six chains, was 22.65 watts.
It seems the water does not remove the thin film of lube. After water and drying, the chains still performed relatively well. However, the lacquer thinner did a number on the lube, and seemed to strip the lube completely. With no lube film, and metal on metal, the friction increased substantially.
Please note: the water does not simulate rain. Riding in rain would kick up some road dirt and grime. I speculate that after riding in the rain, and then if the chain were allowed to dry, we’d see 10-12ish watts of friction. I feel a thin lube film would still be present after rain, but the road grime would increase the friction.
So, it appears that a dry, unlubed chain is very resistive to your efforts to propel the bike, just as it seems when you let your chain get that way in actual use.
Wax with … graphite?
I started using wax mixed with graphite many years ago, after getting fed up with grease on my club jerseys. Learned about it from a fellow who raced tandems and he was fed up with replacing expensive drive trains.
My Litespeed still has the original cassette on it from 2005, with upwards of 25,000kms! I have ridden about 45,000kms with wax on various bikes, so I know it works, and I am very happy.
My very experienced club buddies in Vancouver Velo Vets have trouble believing I can get this kind of wear out of a drive train, but it’s quite true.
Here’s what I do:
I ride a winter road bike and mountain bike in the rain with regular oil on the drivetrain. I happen to use sewing machine oil bought in quart containers.
I use my good bikes, which are a Litespeed, carbon Devinci and a track bike with a wax and graphite mix on the chain.
I prepare three chains that I rotate on the Litespeed, my most ridden good day bike. Each chain lasts about 500km before it gets a slight squeak. This squeak tells me it’s time to rotate the chain. I buy cheap paraffin wax candles at the dollar store, graphite powder at the hardware store and mix up three or four candles with the small package of graphite in a coffee can. Heat it up in a large pot of water. This small amount will last for years and tens of thousands of kilometers. I’m still on my original batch!
Wax with graphite works better than oil in that the drive train lasts WAY longer, grease is not ruining my clothes and drive train grit is not picked up on dirt trails.
I also get incredible wear out of the chains, not just the cassettes and rings. I change the chains after almost 20,000km only because they get side-to-side wear, not stretch wear. I have never had a chain or connecting link break.
After about 500km I switch chains, only when it squeaks. Now and then I heat up the batch of wax and relube the three chains.
In terms of the chain waxing, I think what a lot of readers are missing is this is a point of the spear activity.
Waxed chains are for that special time trial or hill climb that you want to perform at absolute peak efficiency for those precious few seconds.
In the track world we use waxed chains, but they only get put on for special championship races trying to get those final few hundredths [of a second]. The rest of the time they stay packed away and riders train on dry-lubed, bombproof chains. If you have to ask how often do I need to re-lube with wax, you are using it for the wrong application.
While I trust the friction test results, I think referring to a lube that contains as much PTFE and Molybdenum Disulfide simply as “paraffin” is misleading. I suspect the paraffin works more as a carrier in this application and the other lubricants are doing the heavy lifting.
I too have anecdotal evidence of longer chain life with ProLink, though for exceptionally long or wet rides and races I use something heavier duty. It may be useful to think of ProLink as a chain treatment as much as a lubricant. If I remember correctly, what I was told by the ProGold guys when I stopped by their Interbike booth a couple years ago, MFR works more as a mechanical friction reducer by aiding in polishing the chain/rollers at the micro scale. This smoother surface would reduce wear as we have both experienced. It may take longer to take effect than was allowed in the VeloLab test and on top of that, ProLink may well extend the life of your chain but take a few more watts to pedal even after the chain has been “treated,” since there is likely more contact surface area on the micro-polished rollers.
Dear Bill and Rob,
The paraffin used in the Velo test was actually pure paraffin (Gulf Wax brand), without any PTFE (Teflon) or MoS2 (molybdenum disulfide). The Friction Facts wax blend (with PTFE and MoS2) was not tested in the Velo comparison; only pure paraffin was tested.
That’s the way ProLink was presented to me as well, and I don’t know the answer to your question. I was told by ProGold that the chain got smoother over time.
I plan on testing (at Friction Facts) some chains I’ve been riding on for a long time with ProLink and see what happens.
Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.