Do 1x11 Gravel Drivetrains Suck?

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by Mark V on May 02, 2016 at 11:51 PM

Single chainring drivetrains have taken a huge bite out of the mountainbike market, and now SRAM, the industry trend’s main backer, is pushing to put 1x11 on a variety of dropbar bicycles as well. As gravel bikes are akin to mtb for a number of reasons, it’s only natural that the growing market segment would be a ripe target for these products. A key element to getting the wide gear range out of a single chainring is SRAM’s innovative XD-style cassette, which allows a cog as small as 10 teeth to be used. Then the biggest cog is pushed to a startling 42 teeth, giving a total range of 420%. But as head Hugger Byron has stated, the 1x11 XD setup has some big jumps between the gears. He doesn’t like it, and said so in context of the experience. I’m a little more open-minded, probably because I’ve had an XX1 group on my MTB for the past two years. I am well-acquainted with how a 1x11 XD drivetrain feels. What I am going to do here is explain the difference in solid, quantitative terms. And that means dry-ass numbers, percentages, and figures. If you’re such a lightweight that you can’t handle some math, or if you’re not into um….deeper reading because you’re surfing the net on your smartphone while taking a dump, feel free to skip everything I’ve written down to the “summary.” No really, go ahead, I’m totally fine with it. Just know that I will punch you in the face if you want to object to my analysis without actually doing the reading. If you ask Mark V a complicated question, he gives you the fucking answer. I don’t have patience for those too lazy to read and think.

Okay, let’s get started. First, let’s define the scope of the question. The topic is drivetrains on gravel bikes. We are talking about product that is currently available as either on complete bikes or what could be assembled from current components. This means 11sp drivetrains with either double or single chainrings. Triple drivetrains are dead as far as the market is concerned, but I will make a minor detour later on, just to compare for fun. But make no mistake, no player in the industry gives a shit how great you think triples are/were. And anyone who even mentions half-step triples is going to get a punch in the face from me. Getting back to gravel bikes, such machines implicitly need a fairly wide range of ratios. Since width of range and the size of the jumps between ratios are directly proportional, we will limit the discussion to 11-28, 11-32, and 10-42 cassettes, cassettes with sufficient range for gravel bikes. No product manager is going to spec an 11-23 straight-block on a gravel bike, so there’s no reason to talk about it.

Next, what are the parameters that we will be comparing? We want to compare the size of the “jumps” between the gears, ie the percentage increase in wheel development (wheel rotation per crank revolution). Smaller changes in ratios between gears are assumed to be better, and the entire history of bicycle drivetrain development over the last 90 years follows that philosophy. Closely spaced ratios allow you to keep closer to a rider’s “ideal” cadence. If the jumps between gears are too wide, a rider’s pedal action may too often either bog down on too high a gear or spin out on too low a gear. The three cassettes in question share some cogs of the same tooth count, but obviously there will be some differences. So we will consider the increase for each shift on a given cassette as well as the average for all ten shifts (between 11 cogs). Further, a rider almost certainly spends more time in some cogs of cassette than others, so we will consider the average changes for the cogs clustered at the top, middle, and bottom of the cassette. In this case the frame of reference is such that “top” of cassette means the cogs that yield the highest ratios, in other words the smallest tooth counts. The percentage changes are calculated as increases from a lower ratio to a higher; that is, a higher tooth count to a smaller tooth count. For example, a shift from the 12T cog to the 11T cog would yield a 9.1% increase in wheel rotations for every complete rotation of the crankset. We will also consider the overall gear development, which is a combination of the cassette, wheel diameter, and chainrings. Gear development is expressed as gear-inches, and is calculated by the following formula:

X= (chainring tooth count) x (wheel diameter) / (cog tooth count)

in all cases wheel diameter is assumed to be 27” for simplicity

For example:

50x11 yields 123 gear-inches

or

(50teeth x 27”) / 11teeth = 123”

Above are two tables of numbers. Depending on the device from which you are reading, you might want to click on the table to link to a more readable version. Sorry, this website wasn’t really developed around itty-bitty charts and tables.

The upper table compares 11-32, 11-28, and 10-42 cassettes, the 10-42 cassette being the XD-style that would be used as the basis for a 1x11 drivetrain. As you can see the average increase for all shifts on the XD cassette is 15.9% versus 10.6% for the 11-32 cassette. The 11-28 of course has smaller jumps still, averaging 9.8%. But with the common 50/34 compact double crankset, the low gear is only about 33 gear-inches, which is probably not low enough for steeper climbs on a gravel bike with big tyres. Is a 15.9% jump inherently impossible for a rider? Probably not, since there’s a similar jump within the 11-32 cassette (going from the 22T to the 19T). But when we compare an 11-32 cassette to the 10-42 XD cassette, you can see that the XD cassette has fairly constant jumps throughout the range, whereas the 11-32 has tighter jumps in the middle and top end. Since the 11-32 cassette would be used with a double chainring, the rider can toggle between chainrings to keep the chain in the middle of the cassette as much as possible, where the middle five upshifts for the 2x11 setup is 11% versus 15.4% on the XD used by the 1x11 drivetrain. However, a long steep climb would force a rider into the bottom of the cassette, whether he was on a 2x11 or a 1x11. There the score is 13.9% for 2x11 versus 16.1% for 1x11. The difference is real, but whether it is unacceptable to the typical consumer is perhaps debatable. What is clear is that at the top of the range the difference between 2x11 and 1x11 is huge (8.1% versus 15.9% for the top four upshifts).

Now let’s look at the lower table of figures, which compares the range of several drivetrains as expressed in gear-inches. The typical 2x11 drivetrain on a gravel bike would have the 50/34 compact crankset with the 11-32 cassette; we’ll call this a compact double GS (GS for grand-sport, or a medium cage derailleur). You can see that the high gear on the compact double-GS is 123 gear-inches and that the lowest gear is 29 gear-inches. In reality, 29” isn’t that low if you have really long climbs and a bike with a load on it. If you needed lower options, SRAM allows you to use an 11-36 cassette, but that does push the jumps closer to the 1x11 XD drivetrain. Mathematically you could shift the drivetrain range lower if you could reduce the tooth count of the chainrings, but while the 50 tooth ring is probably way too big for the application, 34 tooth is the lower limit that common road cranks allow due to the 110mm bolt-circle-diameter. Indeed, component manufacturers have also noticed this issue, and led by FSA there should be a number of cranksets to hit the market in 2017 that eschew the 110mm bcd standard to allow 48/32 and 46/30 chainring combinations (see this earlier post about gravel-optimized cranksets). But at the moment, 1x11 XD drivetrains certainly offer the most convenient option to lower the gear range; you just swap out chainrings with no front derailleur to adjust. SRAM makes 110bcd ring for 1x11 in 38 to 46 tooth counts. With a 38t ring, the low would be 24”, and even though high end would be just 103”, arguably that would be more than tall enough for a lumbering gravel bike on unpaved surfaces. Understand that changing the size of the chainring does nothing to change the size of the jumps between the gears.

So what do we conclude? 1x11 XD drivetrains consistently have larger jumps between the gears when compared to the 11-32 cassette one would expect to used on a 2x11 gravel bike drivetrain. However, if you consider the range as distinct clusters of cogs within a cassette, the two cassettes differ most dramatically on the high-end and mid-range of the cassettes, whereas the jumps are actually not hugely different at the low-end. Given this information, one would conclude that 2x11 drivetrains would be superior to 1x11 on flat terrain where a rider could choose the either big or small chainring of the double to keep the chain in the middle of the cassette, which would keep the jumps small. It is worth mentioning that the middle of the cassette should also have the least drivetrain friction because the chainline should be as straight as possible, though this is true for 1x11 drivetrains as well. On fast sections, drafting in packs, or downhills, the 2x11 should have a distinct advantage. Considering the usage profile typical of a gravel bike, perhaps this isn’t an advantage that can often be exploited. If the consumer needs an especially low gear, 1x11 is the hands down winner, due to the flexible chainring options. But two or three hours of constant climbing can alter your perception of what is an acceptable gap between gears.

And now as promised, I will briefly talk about triples, the VHS player of road drivetrains. I chose Shimano’s Ultegra 6703, the last quality road triple of real relevance (which shows you what I think of Campagnolo Athena). The 10sp Ultegra triple had 52/39/30 rings, and the widest stock cassette was 11-28 (though a 12-30 was introduced at the end of the 10sp era after Shimano had started to phase out triples). The 10sp triple’s 11-28 cassette wins handily in the mid-range over the 11sp double’s 11-32 cassette, with just 9% jumps in the middle four shifts versus 11% (middle five shifts for the 11sp cassette). And the 10sp is waaaay better than 1x11 XD (9% versus 15.4%). In terms of overall gear range, the 29” low and 127” high of the 10sp Ultegra triple seems a bit top-end biased and ill-suited to gravel. Admittedly, 6703 Ultegra predates the gravel bike trend by several product cycles, so that demographic was not the target of Shimano’s engineers and marketers during development. But if five years ago there were a number of hacks that consumers and customer builders could pursue to widen or lower the gear range, that was a different era of product. And this isn’t a discussion about DIY kludges or eBay as source of vintage parts. Triples are dead and buried; get over it.

Shimano abandoned triples because compact double cranks fulfilled the needs of two-thirds of what was formerly the triple market. When SRAM and Shimano started making mid-cage derailleurs that could fit 11-32 cassettes, that allowed compact doubles to swallow probably 80% or more of the triple demographic. And the triple-loving outcasts leftover can get stuffed, because they weren’t spending enough money for Shimano to justify developing triple-specific integrated levers, derailleurs, cranks, and chainrings. The truth is harsh. And now SRAM is pushing 1x11 because that’s the turf they made their own, a way to pull the OEM rug out from under Shimano’s feet. And frame manufacturers are attracted to 1x11 because it allows them more design freedom when there’s no need to mount a front derailleur and only one chainring to crowd the right chainstay. It’s too soon to say that the front derailleur is an endangered species on road/gravel bikes, but 1x11 is no fluke. The gravel bike is very much an interesting realm of product development, and we can expect cool things in the near-future.

Other considerations? Weight may as well be mentioned. In not-so specifc numbers, SRAM’s long-cage X-HORIZON rear derailleurs are heavy when comparing examples of equal quality, and then they are somewhat more expensive. The XD cassettes are somewhat heavy and fairly expensive at the high-end. But the lack of shifting bits on the left lever and omission of front derailleur paints 1x11 as a win in both cost and weight.

In my opinion, 2x11 makes the most sense for the majority of the gravel bike category. At the custom frameshop where I help with the bike spec and do the actual assemblies on the finished framsets, there have been several bike designs that were tailored for 1x11, trading the front derailleur for big tyre clearance. However, if double cranksets better suited to gravel had been available (smaller chainrings but not so small as the typical MTB fare), the framebuilder and client together might have chosen 2x11. A light bike with 1x11 can be a lot of fun on choppy, variable terrain when you’ll be working rapidly across the cassette, but long, steady stretches into the wind or up a long pitch begs for finer steps between the gears.

SUMMARY

For gravel bikes, 1x11 drivetrains have bigger jumps between the gears compared to 2x11 drivetrains, and this is most distinct in the highest gears and in the mid-range of the cassette. Theoretically, the 2x11 should be superior shifting (ie have closer shifts) mainly on flat and fast terrain where the top of the 11-32 cassette has much closer ratios…. or the choice of two chainrings allows the rider to stay in the middle of the cassette more often. On extended climbs, one would expect to stay at the bottom of the cassette where the difference between 2x11 and 1x11 XD drivetrains is smaller, but the longer the climb, the more you’ll want tighter jumps between the gears. However, when having a gear that is low enough becomes critical, the 1x11 drivetrain can easily accommodate a lower low gear by swapping the chainring to one of a lower tooth count, though at the expense of top end. There is no convenient option to do this with 2x11, until cranksets targeted at the gravel market become available with something smaller than a 34tooth inner ring. A 1x11 drivetrain may allow bike manufacturers to optimize the frame design in ways that would otherwise be restricted by the prerequisites of accommodating front derailleurs and multiple chainrings. These possibilities may sway a consumer’s decision to choose 1x11.

If you like simplicity of use, structure, and maintenance, 1x11 with SRAM’s 10-42 XD cassette is for you. If you know you’ll need a hella low gear and can give up some high-end gear, go 1x11…or maybe you should train and get stronger. If you like tightly spaced shifting, then choose 2x11…or you could shut up and learn to pedal with some suppleness.

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Riding in the Woods is Fun

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by Byron on May 02, 2016 at 1:24 PM

labeling someone a "roadie" is to miss out on the beauty of what it means to be a CYCLIST. J. Stukel knows. #dropbarsnotbombs

A photo posted by Tommy Everstone (@crc_hurl) on


Hurl is right and I saw this photo on Instagram, just as I was writing a post about Issue 35 Into the Woods, that dropped on Friday. Of all the words I’ve been writing about adventure, gravel, and roadies riding offroad on dirt

It’s really fun

are the most concise. We try to limit car sightings to one a hour, at max and sometimes don’t see them for hours. That’s what riding in the woods is about: no cars+fun. In the issue, I share stories about the Boone and Diverge, 1x11 road is reviewed too. The issue costs $3.99 or $14.00 annually. It’s available on iTunes and the Web.

Sdg

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One Day In April - Trailer

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by Byron on May 02, 2016 at 1:11 PM


“One Day in April” is a feature-length documentary that chronicles the triumphs and failures of four collegiate cyclist teams competing to win the Little 500. The film is a bittersweet portrait of life in the midwest and the drama from training through race day.

And I don’t think we’ve seen any full-length media about the Little 500 since Breaking Away in 1979.

At a time when collegiate athletics is navigating an increasingly uncomfortable intersection of profit and competition, the Little 500 remains an example of pure sport in America’s heartland. Through the stories of the individuals who make up the Little 500 community, “One Day in April” is a testament to the virtue that sports build community and forge kinships rarely savored otherwise.

The expansive narrative of friendship, failure, and redemption plays out across a cast of characters that includes experienced veterans, accident-prone rookies, and alumni coaches who treat the Little 500 like it’s the Indianapolis 500. In a once-a-year event like this, there is no tomorrow.

They still race the Little 500.

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New Belgium Brewing Bicycles

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by Byron on Apr 27, 2016 at 12:31 PM


For the first time ever, New Belgium Brewing is producing its coveted special edition cruiser bikes in the U.S., using Detroit Bikes, a Detroit-based bicycling manufacturer and North America’s largest bicycle producer. Just in time for warmer weather the bikes are now hitting the streets through New Belgium fundraisers, giveaways and as one-year anniversary gifts to New Belgium co-workers. The partnership has created new manufacturing jobs in Detroit with the company doubling its workforce from 20 to 40 employees.

And, see our reviews of the Type B: Practical Transportation on Medium, Clueless Asks for Bike-Buying Advice.

Maybe we’ll have some of those bikes are our annual Mobile Social Interbike, which has been sponsored by New Belgium for the past several years.

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Working on Issue 35

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by Byron on Apr 26, 2016 at 3:14 PM

sdfs

As I shared on Instagram this morning, this photo is from Issue 35, and a story about devotion dropping later this month. 34 Truth is available on iTunes or the Web now.

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N1NO 18th World Cup win

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by Byron on Apr 25, 2016 at 12:56 PM

An adorable thing about the Aussies, is all their crazy sayings—now imagine one of those outback colloquialisms being said with a thick Swiss accent. That’s why I laughed so hard this morning when I read, “We are not here to fuck spiders.” In American parlance, that means, “Not here to fuck around, or “Here to get shit done.” And that’s exactly what Nino Schurter did in Cairns last weekend with his 18th World Cup Win. See the replay on Redbull and a quote from the best bike-biz PR I’ve read this year, maybe ever.

SDf

It’s quite a ways to travel for a 90 minute mountain bike race. With the change in time zones and climate, plus shipping all the equipment, this is a logistically difficult and expensive journey. This is why you better get something out of it. And this is exactly what SCOTT-Odlo MTB Racing did. Or how the Aussies would say: we are not here to fuck spiders!

That deserves a hashtag: #notfuckingspiders

The winning bike powered by the World Champion and the brand new 12 speed SRAM Eagle drivetrain.

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Front Derailleur Repurposing

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by Byron on Apr 22, 2016 at 9:21 AM


A few ideas on what to do with all those discarded front derailleurs from Fairdale Bikes and some humor after a sad day.

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Prince: Let Me Guide U

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by Byron on Apr 21, 2016 at 1:33 PM

Just as I was getting into my day, finishing a batch of photos to share; and, then the news that Prince died…reflections of course, memories, and wondering why so many musical artists of my generation are dying. My friend Anil Dash shared this Soundcloud

I’m so sad that Prince is gone. I think everybody who knows me knows he was my favorite artist, but it might not have been obvious that I didn’t just appreciate his music and his artistic work, but also what a pioneer and innovator he was creatively and in business and in culture.

I just wanted to share this song from 2 months ago, when Prince played “Purple Rain” in a new way, just on piano, like he was writing it for the first time. He never really sings a full verse, he never plays the guitar solo, he never fully gives the audience the cue to sing along with him. He was still just mourning the passing of Denise Matthews (Vanity), and this was a song he’d played for 33 years but it still sounded new. Prince dedicated this tour to his father, but I felt this performance of Purple Rain may have been just as dedicated to the son he lost 20 years ago. It haunts me.

Goodbye Prince, and thanks for so many wonderful memories.

Back in the blogging days I’d meet Anil at various conferences. It was his ‪Prince‬ stories I looked forward to the most. One time he shared with me a bootleg of Prince playing a face-melting version of a Whole Lotta Love. It’s on rotation now with this most haunting version of Purple Rain.

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Rasta Quick Release Skewer

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by Byron on Apr 20, 2016 at 11:06 AM

hh

Considering how the history of the bike industry in America is infused with cannabis, I’ve wondered why a progressive company didn’t embrace it; especially, in cities where it’s legal or tolerated. Well, today, Paul Components did and happy 420 day to them. As they shared

In light of April 20th, Paul components shows their festive colors with the Rasta Quick Release Skewer. The internal cam design always holds tight, has perfect foolproof alignment, and is fully protected. Skewers are available in your choice of lengths: 100mm; 130/135mm; 170mm; 190mm. The internal cam design always holds tight, has perfect foolproof alignment, and is fully protected. Skewers are available in your choice of lengths: 100mm; 130/135mm; 170mm; 190mm.

Each skewer is made to order, with the quality and precision that Paul Components has blessed the biking community with for almost 30 years. To order, just pick the length and select ‘Rasta’ in the ‘Finish’ dropdown. Show a little Rasta love wherever you ride.

I think by now you should know we prefer thru axles for our disc brake road bikes, but when a bike needs skewers, this is a great choice and costs $55.00. If you didn’t notice, Paul’s skewers were attached to the Triple 3 Fab bike Mark V profiled in Issue 33 Crafted.

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Road Disc Will Prevail

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by Byron on Apr 19, 2016 at 10:28 AM

As my colleague, @bikejourno tweeted this morning

with an edit of the Merida Scultura Disc


While not imported in the States, you’ve probably ridden a bike made by Merida, under a different brand name. They’ve been in business for 25 years and following the Paris-Roubaix disc injury, released this statement.

Following the injury at the recent Paris-Roubaix race and the following preliminary suspension of disc-brakes by the UCI we would like to take the opportunity to give a statement as one of the two bike-manufacturers who used disc brake equipped bikes in the event.

For years and strengthened by the overwhelmingly positive feedback from TEAM LAMPRE-MERIDA (who concluded two weeks of world-tour racing to test the equipment under serious race conditions), MERIDA continues to believe in the future of disc brakes on road bikes. We are convinced that the added safety aspects such as better modulation and braking performance especially in the wet and when cornering, avoidance of rim heat up on long descents etc. will help the prevention of crashes and outweigh the potential risks as passive member of mass crashes.

However the happenings of the recent event has shown that further disc technology improvements should be made to reduce potential risks (for example rotors with rounded edges). For this purpose, MERIDA and other leading bike brands are in communication with disc brake manufacturers to push this development forward.

MERIDA will do its utmost to support the safety improvements of disc brakes during racing so that not just the amateur rider but also the pro-peloton can benefit from the long lists of disc brake benefits.

In my commentary about disc brakes on Medium Bicycles, I shared that no new molds are being opened for caliper brakes. There is also an unprecedented flurry of engineering activity in Taiwan right now, coming up with a fix, that should’ve been in place before the start of the season. Why the UCI is locked into a 1990s mindset is another matter. The impact to us is what the pros ride has never been more irrelevant to what we’re riding. I’ll say it again, when it comes to road bikes, get the disc, like this one.

as

If you don’t understand why road disc is better, the marketers have failed at their job. Well, you can ignore them too because they sold aero and marginal gains instead of massive gains in braking and bike-handling technology. The Merida Scultura Disc is an example of the advances, and so is the Trek Boone or Domane SLR.

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