The Drag of Chain Efficiency, Part I

FFWippermann Test4

The quest to make the bike go faster never ends. Once the big things are taken care of, it’s time to focus on the little things. And when the little things seem dialed, it’s probably a good idea to check back on the big things, just in case something has changed. And then back to the little, just because something else might have been overlooked.

When I read about Friction Facts and their claims that variations in chains and chain lube results in a measurable difference in terms of energy cost to propel a bike, I was intrigued. Especially when part of the solution was a proprietary paraffin mix. A semi-secret sauce? How much better could high-tech old-school waxing be? I purchased the set of reports they had on offer to take a look. Turns out, the differences can be big.

This piece gets fairly technical. There’s a reason. I’m trying to explain everything on the assumption that the reader isn’t familiar with every little bit of info. And, as with watts, little things can add up to make big differences.

Chain and Drag
Friction Facts tested five top-of-the line ten-speed chains, with five samples each, and averaged the results. According to Friction Facts, the standard Wippermann Connex 10S1 chain, Wippermann’s lightest chain, a chain I’ve run on my bike many times, has 8.85 watts of drag straight out of the box when the five samples tested at 250w were averaged. In the tests, the 10S1 also showed the least variation from chain-to-chain, with the spread between the least efficient and most efficient a total of .45w. And when the 10S1 was relubed with light oil, the friction dropped to 7.04w at 250w. In other words, a 1.81w difference (0.724%) is found by changing lubes. And the differences are much bigger for “optimized” chains, with many of them coming closer to 5w, a whopping 2%!

In case you’re wondering, the oil used for the Friction Facts tests was a non-cycling oil. Specifically, an electric motor oil from a  company that doesn’t make or market cycling-specific lubricants. This was a deliberate choice, both to show no favoritism to any bike-specific brand, and because the oil has no additives, like Teflon, that could potentially affect results.

1.81w is pretty small, but all things being equal, can result in some noticeable differences. To give a sense of what kind of difference 1.81w makes, we went to Analytic Cycling. If you haven’t been to the site, it is a must-visit of the tech set. The calculators are incredible.

Utilizing the Speed For Given Power calculator, you can quantify what 1.81w means. Because it is in a part that directly propels the bike, the wattage can be directly added to the rider’s power. Assuming the default frontal area, average drag coefficient, riding at sea level on a typical asphalt road and no wind, a 150lb rider pedaling a 17lb bike at 250w goes 11.22 meters per second or 25.01mph. Take that 1.81w savings and add it to your power, and the same rider goes 11.25m/s or 25.17mph. In other words 3cm farther per second translates into .16mph increase in speed. Or .64mi in four hours—over a kilometer difference in a four-hour ride by changing chain lube. Even at an easier 200w, where the same rider is doing 10.78m/s, the rider with the lubed chain is still traveling 3cm faster every second.

This is why looking for “marginal gains” is something just about everybody should consider. Marginal gains is a term the Sky professional racing team has popularized. Essentially, it means that accruing tiny improvements, on the order of one percent or so, wherever they can be found, can add up to race-winning differences. It’s hard to imagine that people wouldn’t want the cumulative effect of small gains, even if they can barely feel them. And it’s easy to see why professional cyclists should care: ride the 80 hours or so of a Grand Tour as a time trial, that marginal savings could be worth over 20 kilometers, or almost a half-hour.

In other words, 1.81w is a big deal. Wondering if the data was reliable, I got in touch with Tom Petrie, whose company, Velimpex, imports and distributes Wippermann chains. Presumably a chain expert, I figured he might have something to say on the matter. He got back to me with a proposal. Test two Wippermann chains out in real-world conditions; see if the difference is measurable. One was the stock 10s1, the other was the stock 10s1 with the Friction Facts chain wax applied. He sent one chain directly to me, another to Friction Facts, who did their magic and sent it my way.

Jason Smith, the man behind FF, sends a report along with each chain he optimizes. The particular chain he sent had 5.51w of friction, 3.34w lower than standard, with factory lube, in the range of what he reports is possible with Wippermann, and above the 5w guarantee he has for the other chains he optimizes. But his reports indicate that he’s been unable to get the Wippermann chains down to 5w. Still, the 3.34w drop in resistance takes that same person above from going 11.22m/s to 11.28m/s. an extra 6cm per second, an extra .22mph, raising that same theoretical rider’s speed from 25.01 to 25.23mph. After four hours, you’ve gone .88mi farther.

Wippermann comes with an advantage in chain testing. Their Connex link is a tool-free, reusable master link, which makes swapping chains easy. It’s also something that Smith recommends using with all the chains he optimizes. This way, you can warm up on your standard chain, swap out the standard chain for the optimized one in less than a minute, put in the rear disc, clean hands, and head for the start house.

Testing
I started with the two Wippermann 10S1 chains. My basic idea was: take them out of the box, size them identically and then alternate chains on repeated tests. Do many indoor sessions so the tests are repeated over time, and then take the optimized chain out and see how long it goes before it starts squeaking. Smith actually runs the chains he optimizes for 20 minutes before sending them out, so there isn’t a need for any break-in period. And, as he believes the treatment is good for around 200 miles, there’s little reason to waste any mileage on breaking it in. Since that chain wasn’t going to be cleaned, we also started with the standard chain straight out of the box, no lubing or cleaning. It would be our daily chain and would only get wiped down, if necessary, before an indoor session, and only lubed when absolutely necessary. This way, I figured I’d be treating the regular and optimized chains the way people looking for performance advantages would be.

The plan was to ride with them doing repeated runs on my Kreitler rollers at three different loads: 150, 250, and 300 watts, to see if I could find any differences at the different power numbers and if those differences could change depending on load. I’d do one chain for a half hour. Then the other.

The only way to know if the differences, assuming there were differences, are actually there, is to control as many variables as possible. I used a digital pressure gauge to make sure the tires were within 1psi of 105psi for every ride. I made sure the room was within a narrow temperature range of a few degrees Fahrenheit. I let the bike sit in the room for at least 15 minutes before starting to make sure the power meter was properly acclimated. I zeroed out the power meter offset before each test. I either used the rollers with no resistance or with the headwind unit attached and the gate closed.

A perfect scenario would have been to have a test bike just for riding indoors. But I went with my regular road bike that was going indoors and out in the winter. So there could be variations on bearing drag and the wear of the tires could potentially make a difference. I started the test on Vittoria Rubino Pro tires, but as they looked pretty worn and was worried they wouldn’t last through the test period. So, after a few runs, I swapped in Specialized Armadillo Elites, a nice slow super-durable tire.

I also ended up having to send back my Quarq Cinqo and replaced with a Quarq Elsa. This was a potential boon, as the Elsa is supposed to be more accurate than the Cinqo. But here you’ll see the limitation of testing with a powermeter. The Cinqo has a claimed accuracy of +/-2%, a 4% potential variation. Assuming +/- 2%, 3.34w is equal to the variation at 83.5w of power. The Quarq Elsa has a claimed accuracy of +/- 1.5%, where the margin of error spread equals the power savings at 111.3w. And after we changed chain rings and tested the accuracy thereof, we ended up recalibrating the Elsa.

The idea of testing out the chains at three different loads, 150, 250, and 300 watts is to find if the change in load could result in any differences. I ended up riding at 154w and 247w, and the 300w ended up being a bit too optimistic in terms of what I could consistently hold for fifteen minutes.

I took the chains out of the boxes, sized them, and then kept them separated. They’re easy to tell apart at the start. One has wax flakes all over it and the links feel stiff to the touch. It’s a bit hard to believe the chain is faster that way. But, as I started to pedal, the wax flew off so quickly on the first run that there was no need to clean it. The other one was slightly greasy. I left it as is.

 

Tune in tomorrow for Part II.

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11 comments

  1. grolby

    “ride the 80 hours or so of a Grand Tour as a time trial, that marginal savings could be worth over 20 kilometers, or almost a half-hour.”

    Come on. Grand Tours aren’t run as 3400 km time trials, so this argument isn’t actually all that relevant to the pro cyclist. And I’m sorry, but no amount of fiddling around with bike calculators will demonstrate that 1.81 watts are “a big deal.” By themselves, they just aren’t, period. It’s not that I want to dismiss potential power savings from reducing mechanical friction as useless or irrelevant, because I I don’t think they are, but I think that the subject deserves to be treated with more nuance and a more realistic understanding of what the trade-offs are. It makes perfect sense to argue that mechanical friction should be considered by racing cyclists, as there are power gains that come without any training or physiological cost to the rider. The question then becomes whether the individual rider considers that “free” speed worth the economic cost of obtaining it. That way we can consider that trade-off in a more reasonable way, with the free, though relatively small, gains from reducing friction on one side, and the generally high monetary cost of parts that reduce friction on the other. Balanced, of course, against the monetary and/or emotional investment the rider has put into getting results. And we can dismiss claims that 1.81 W are “a big deal” as the patently silly exaggerations that they are.

  2. Mike

    Grolby:

    In general I think manufactures calculations claiming savings on drag are overhyped (and likely wrong). That said, 1.8W from a single component (if right) is nothing to scoff at. I know when I wasn’t fat/out of shape/generally lazy I could hold about 310W over 30min. 312W wasn’t happening. And 300W felt much easier. Maybe I’m weird, but 1.8% at the margin is really noticeable. 100W vs. 102W. Sure, whatever, that’s a hiccup. But at the end is when you feel it, and that last 1.8W is what’s going to suck, not the first 1.8W. If I get that for free (or $20), I’d take it any day.

    Also, if I could eek out 1.8W each from 5 different components (for example from careful selection of my chain, wheel bearings, bottom bracket, derailleur pulleys and chainrings/cassette), I would be stoked in a time trial for the extra 9W. Hell, I’d be stoked anywhere with the extra 9W.

  3. Michael

    As an engineer I have to disagree with Grolby, somewhat. On a casual ride, the sort that probably most of us do most if not all of the time, a 1 or 2% boost isn’t going to make much difference and if the point is to get in shape we might be better served working a little harder than using some super lube. On the other hand, consider a typical road race. After two or four hours of pelaton and attempted break away’s, if you are in the lead group at the last fraction of a mile and now you have to put everything you’ve got into a sprint finish (where the gap between first and thrid is less than a second). That 1% difference is the difference between the guy in the middle of the podium and possibly the guy watching from the sidelines.

    On a completely unrelated note, considering the following statement:

    “Wippermann’s lightest chain… has 8.85 watts of drag straight out of the box… when the 10S1 was relubed with light oil, the friction dropped to 7.04w at 250w. In other words, a 1.81w difference (0.724%)”

    That 0.724% is clearly based on the over all firction of 250W, i.e. 1.81/250, in fact I would say you are comparing a lubed to an unlubed chain so the convention is 1.81W out of 8.85W, i.e. 1.81/8.85 or about 20.5% improvement. (After all a 100% improvement in the chain should net 0W of effort out of 8.5 possible Watts.) There might be some machinest out there who disagrees but from a technical standpoint I think the ideal way to report this is:

    An out of box Wippermann represents 3.354% (8.85/250) of total frictional losses. Use of fancy super lube results in a 20.5% reduction in chain inducded frictional losses, or 0.724% of overall frictional losses.

    Sorry if I’m being annoying and pedantic but I had to read the paragraph a few times to get the numbers to make sense to me. :p

  4. Winky

    A 2% difference can be a BIG deal if it means the difference between holding that wheel in front on a long uphill drag, (or when trying to close down an attack,) or being droppped by half a metre, that becomes 2m that becomes 10m that means the end of your race. Or in a crit, a little less drag can mean that you close the gap to the rider in front out of a corner in 20m or in 100m. That adds up to a big difference in effort.

    Arguably, this stuff can matter more in mass-start racing than in TT where a couple of percent is only that. In mass-start racing, closing down gaps quickly to get back in the draft and save energy can be an all-out effort where every little bit might count.

  5. Dustin

    It’s only good for 200 miles? So in a ProTour race they’d need a new chain every day?

    How well does it work in real life conditions, not a test lab? You know, rain, dirt, dust, road grime, sand, etc?

    A proprietary lube you can’t apply yourself that only last 200 miles is a joke for anyone who isn’t paid to ride IMO.

  6. Scott G.

    I am convinced, I am trolling ebay for inch pitch block chain right now.
    The 200 hundred mile limit can be broken with an oil bath full chain case,
    probably better aerodynamics too.

  7. Rod

    @ Dustin above:

    I like data. I like science and engineering. I purchased these tests results because they are relatively inexpensive and interesting to me. More than, say, two issues of Bicycling.

    The paraffin-lubed race chains were never intended by FrictionFacts to be used as “everyday” equipment, but to those situations where you really want all the advantages. So for those cases where you put new lube to your BB, cleaned your bike thoroughly, etc. He mentions TTs.

    Futhermore, he’s made the recipe “public” so everyone with the time, inclination, and attention to detail can paraffin lube his chain to his heart desire. He actually recommends doing so in batches since it’s so labour intensive. He made the announcement that he would stop selling those chains since it got in the way of actually testing equipment.

    Finally, he did test the chains after grime, dust, etc. Different test. Of course, the test itself is not “on the road”, since few things you can put on your bike are sensitive enough to measure 1 W difference at 300 W pedaling. But this is one perk of criticizing the tests after reading them, not before.

    Is this worth the time and money? I won’t be paraffin waxing my chains. And I won’t be buying a Berner rear derailleur for marginal friction savings at $400+. But I certainly appreciate that someone is testing them.

  8. MattC

    I’d read that report on Velo News months ago (about how Parafin was the least-power loss lube tested). I got myself a little crock-pot from Wallyworld (about 12$, and a 2lb block of wax for about 6$ at a craft store….this will be enough to ‘wax’ my chain many dozens of times. Cleaned my chain REALLY good, then gave it the hot-dip treatment.

    I can’t say that I notice any diff in my power…but I do have this to say: My drive train stays perfectly clean now. Forever! I pull the chain every 200-300 miles (just becasue I’d rather wax it too soon than let it go dry), and re-dip it. It’s not that hard, you just need to have a chain w/ a removable link (I now only use KMC chains…the cheapest ones you I can buy…they are lasting me just as long as the stainless Wippermans I used to use at a FRACTION of the cost).

    Even if there was/is no addeded benefit in power loss whatsoever, just the spic-n-span drivetrain (AND frame…it’s white) make it WELL worth it. I wish I’d heard about this YEARS ago! And I don’t use any special ingredients in my wax (some people add graphite or other things..I just use the straight parafin, dip it for a good 5 minutes or so (when I’m sure it’s totally at temp and the wax has penetrated all the pins), pull it out w/ my piece of bent-wire, let it cool some, and then give it a good wipe-down to remove most of the unnecessary outside wax. Let it totally cool off and then break all the links free (by running it over the edge of a 2×4 a few times at a 90 degree angle) and install. It runs super-quiet too!

  9. grolby

    I’d like to emphasize again that I think the power savings are relevant, and worth considering, even if they are very small. I just think it’s misleading to use calculations to try and claim that they are large. Of course 2 watts of drag can add up to be enough to make the difference between winning and losing – this sport sees results decided as a matter of seconds. But of course, so can 20 watts difference between two riders be the difference between winning and losing, and is far more likely to be decisive! Of course a couple of watts can make a surprisingly big difference, but the magnitude of the difference they make is still much smaller than the magnitude of power differences from better aero positions or differences in fitness. What I’m saying is that removing 2 watts if mechanical drag from context, when said context is 1: they are among the very smallest of a myriad of factors that can effect the amount of power that goes to the road, and 2: they are among the very most expensive watts a rider can save, in terms of dollars per watt, is EXTREMELY misleading.

    The point being that no one except perhaps Team Sky has unlimited resources, so the real question is about bang for buck. Making those two watts out to be a huge deal might give the impression that the bang for buck on reducing mechanical drag is good, when it’s among the most expensive ways to gain speed there is. And I think that’s important.

  10. mark

    I was going to give my experience in this but MarkC above said it exactly. I was curious, tried it, and love it. My investment was ZERO. I took an empty pasta sauce jar and a dozen of my wife’s un-scented votive candles. Melt the was in the jar in a sauce pan of boiling water. put the chain in and let it sit in there for a while. pull it out, let the wax cool and harden and put the chain back on. I reuse Sram quick links a couple times and keep a few new ones around if they start getting loose. From a clean-drivetrain standpoint, NOTHING beats this. I ride every day and only re-wax about once a month. The wax on the outside of the chain basically falls off right away, which if fine. It’s the wax that’s inside the chain that is the key here. It stays where it needs to stay, on the inside between the links. Wax isn’t a great lubricant but what it does have is crazy film strength. Liquid lube just can’t stay in between the chain pieces once pressure is applied. What might be a superior lube at low pressure just can’t stay in between the parts at higher pressure.

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