First published November 4, 2017
With more and more sprockets on our wheels, do we still need two chainrings up front? We take a deep dive into the pros and cons of 1X gearing.
The drivetrain on a modern road bike has evolved loads since the early days when you turned a lever to move the chain to a different sprocket. Electronics are now commonplace and cassettes with ever-wider ranges provide enough gears to tackle even the steepest mountain climbs.
Most modern road bikes use two derailleurs to move the chain across the cassette and chainset, and it works well thanks to many years of product development. We probably take them for granted. But there's a move in some parts of the cycling world to simplify the drivetrain and it threatens the future existence of the front derailleur.
The arrival of SRAM’s 1x11 drivetrain a few years ago, a gear system that ditched the front mech and instead combined a single chainring with a wide-range cassette, provided another path. Such drivetrains have become hugely popular on mountain bikes and we've seen cyclocross and gravel bikes also being specced with single chainsets in recent years. Could the same happen to road bikes?
What are the benefits of 1X gearing?
The simplicity is certainly appealing. With just one shifter, changing gear is much more intuitive than having to manage the front and rear derailleurs. For beginners, that's an obvious benefit. There’s one less component to fail as well (though front derailleur failures are rare) and on bikes designed for wider tyres, removing the front derailleur can provide additional clearance around the rear wheel and seat tube area.
Read more: Beginner's guide: understanding gears
A short history of the front derailleur
Early users of double chainsets didn't even bother with front derailleurs; they pushed the chain from the large to small chainring with their heels at the bottom of a long climb, then stopped at the top of the hill to manually lift it back to the big ring. In the 1930s, French cycle tourists began using mechanisms to move the chain, as they realised being able to change gears was useful on the flat as well as when you had a long climb ahead.
Front derailleurs of the 1930s were usually actuated by cables; rod-operated front derailleurs appeared in the 1940s, and provided very quick and efficient shifts. You had to reach down towards the bottom bracket to operate them, which looks awkward to modern riders who are used to brake/shift levers, but was reportedly quite straightforward.
Read more: First Ride: SRAM 1x Road
Since then, the front derailleur really hasn't changed much at all. It's still a basic component, comprising two metal plates that shove the chain across the chainrings, and the stiffer those plates the better the shifting. But making plates stiffer by making them thicker also adds weight, so gear makers have added ramps and pins to the chainrings, bringing a real improvement in front shifting performance. The biggest recent development has been the addition of a motor in the electronic systems made by Shimano, Campagnolo, SRAM and FSA.
The 1x charge – the industry speaks
But the cycle industry is in a great period of technological development at the moment and everything is up for change. Chainsets have evolved from triples to doubles over the years with loads of configurations available, but a definite trend towards lower ratio setups like a compact, semi-compact and most recently, sub-compact. So if lower gears are popular, why not go all the way and use a smaller single ring?
For mountain biking, a single ring chainset makes a lot of sense. Changing gears is easier with just one gear shifter, there's one less thing to malfunction, mud and ground clearance is improved, weight is lowered and suspension designers are freed from the limitations of having to factor in a front derailleur when locating pivots. And any loss in gear range is compensated for by a wide-range cassette, with SRAM’s introduction of a 10-42t cassette and more recently 10-50t with its 12-speed Eagle groupset.
SRAM has been instrumental in the popularity of single ring drivetrains, but SRAM’s Global Drivetrain Category Manager Ron Ritzler doesn’t think fans of the front derailleur need to worry just yet.
"Will the front derailleur disappear? Probably not yet as there are certain users, like some elite athletes, who need the range and the steps to perform at their best – but can it kill the front derailleur for users who spend their time in cyclocross, commuting, adventure riding and in events where fast precise single ring performance is preferred; heck yes,” he tells us.
“We still make front derailleur and 2x rings that work really perfectly, but we love the fact that there are some many people using road bikes in new ways that make 1x the right choice."
While SRAM has been cheerleading the benefits of single ring drivetrains, Shimano isn’t really embracing it. Shimano’s Ben Hillsdon says the versatility of the double ring setup is just too good to ignore.
“Essentially the front derailleur doubles the number of gear ratios available to a rider, and, therefore, gives riders smaller steps in shifting between their biggest gear and their lowest gear,” he says. “That means riders have a wider range of gears, a smoother pedalling experience and their cadence (ie leg speed) can stay constant.
“That, in turn, brings a physiological benefit as muscles and joints are saved from being overworked, which can be crucial when it comes down to the sharp end of a race. The versatility of a double-ring setup is that you can go anywhere without compromise. However, for those riders choosing simplicity, our strategy is to offer drivetrains that can be set up in many different ways for different styles of riding.”
Read more: Your complete guide to SRAM road bike groupsets
Since we spoke to Ben Hillsdon, Shimano has backtracked a little though, introducing 1X options in the GRX range of gravel bike components. Okay, a gravel bike isn't a road bike, but there's no reason you couldn't use a gravel bike transmission on a road bike as long as you can get a top gear high enough for mountain descents and sprint finishes.
In fact, that's exactly what 3T have done with their Strada road bike, which now comes in a version with Campagnolo's 1X13 Ekar components. Ekar is intended for gravel bikes, but 3T clearly don't believe in discipline boundaries, and who's to say they're wrong?
But a front derailleur gives you more gears, right?
One of the biggest advantages of the front derailleur was a big increase in the range of gears. That was an obvious advantage with a 5-speed cassette many decades ago. Over the years, the number of sprockets on the cassette has increased and is now up to 11, 12 or even 13.
Not only has the sprocket number increased, but the size of the sprockets has gone up: most racers predominantly used 12-23 cassettes a few years ago, but 11-30 is now common in the pro peloton and many sportive bikes now come with 11-34 cassettes.
Of course, removing one of the chainrings reduces your available range so to combat this SRAM introduced a whopping 10-42 cassette. It was instrumental in winning over mountain bikers as it was possible for a single ring drivetrain to offer nearly the same gear range as a conventional compact drivetrain.
Read more: SRAM Rival 1 review
How does a single ring drivetrain compare to a conventional drivetrain? Favourably, if you look at the numbers. Combine a 44-tooth single chainring with an 11-36 cassette and you have a gear range from 33 to 108 inches. That’s very nearly the same as the 32.8 to 122.7 range that a 50/34 and 11-28 setup provides, a setup many riders still use, though the latest off-the-peg bikes tend to have an 11-32 or 11-34 cassette.
You can adjust the size of the chainring and the cassette to tailor that gear range to suit the geography of your local terrain and riding style, whether solo touring rides or racing, much like you modify a current drivetrain with different chainsets and cassettes depending on whether you want top-end for racing or low-end for riding in the mountains.
While the gear range compares favourably, where the 1x setup falls short is in the jumps between the gears. This will concern those cyclists who like to be in the perfect gear for the optimum cadence at all times. How big a concern the larger jumps between gears will be to you depends largely on the type of cyclist you are, the sort of riding you do and your terrain. There is much work being done to provide cassettes that can help smooth the transition in the most frequently used gears, with 3T's Gerard Vroomen developing two versions of a 9-32t cassette that looks to be a good choice.
So should you ditch the front derailleur?
That depends. There are clear advantages and disadvantages to a 1X drivetrain at present. It’s unlikely we’ll see the front derailleur confined to the history books anytime soon, especially given Shimano’s dominant position in the market. That'll certainly be the case for regular road bikes and especially race bikes where tradition rules.
Where we're seeing single ring drivetrains really start to become a lot more popular is on bikes where the disadvantages are outweighed by the advantages offered by a simplified drivetrain, where the ultimate range isn't as critical and where the bigger jumps aren't as much of an issue.
Read more: Will your next bike be a gravel bike?
We’re talking about cyclocross bikes (where many racers have been going single ring for many years already with home-brewed solutions) and the gravel and adventure bike category where 1X is as common a transmission option as 2X. But with the likes of the 3T Strada and Whyte Wessex One, two road bikes designed around 1x11 drivetrains, we could be looking at more road bikes devoid of front derailleurs in the future.
Ultimately, though, the modern double-chainring transmission is too good for many cyclists to want to make a radical change. But the rise of wide-range cassettes does provide an interesting alternative that will appeal to many cyclists, which means we might see a few less front derailleurs on road bikes in the future.
Do you ride a bike with a single ring drivetrain?
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125 comments
I get the preference for closer shifts, especially for racers.
The range argument doesn't stack up so well. As in the piece, the right set up with 1x can pretty much equal the range of 2x. If you factor in the ratios you "lose" through not cross shifting it's even closer.
I work as a bike mechanic and one of the the components that frequently doesn't work as well as should is the front mech. By that I mean narrow cages, bad machining etc. limit the range available on either front ring even more. I started reading this because I've just ordered a 1x setup to try instead of 2x because I'm fed up of the chain hitting the front mech half way up or down the cassette. I always feel a drivetrain should be as quiet as possible!
I'm certainly no racer the days and I'm not expecting to miss anything but we'll see!
Doubles and tripls will never die. The only reason SRAM went for 1x was that they have never been able to make a good quality front mech.
Replacing a double with a 1x makes sense for some applications especially for MTB/Gravel/CX, but for road bikes and especially touring bikes a 1x will never give the same range while still allowing a closer ratio rear cassette for optimum cadence.
I have a gravel bike with 30-39-52T triple and 11-34 9 speed cassette on the rear giving me 27 gears and 536% gear ratio (many will say ah but some of those gears are just the same, so redundant, but I can reach all 9 gears with the 39T ring and I then have the 30T for climbing and the 52T for fast flats/descents.
Also having serviced many of the new 12 speed cassettes, the 10T rings wear our very quickly, and the SRAM SX and NX mechs and shifters are of such poor quality that I often have to replace them with GX or higher mechs for customers, so service costs are actually much higher than a traditional double or triple where you can move around the cassette chainring combos to increase life.
I live in a flat area. we have quite enough hills. they are not very high, but long. So I ride 52T chainring with 11-32 cassette, and that's fine. I guess, that 50T with 11-36 drivetrain might be more comfortable. And I see no need in front mech
If I ride my 1x CX bike on the road alone, it’s fine. Took it on a fast group ride with road tyres on, the pace was dictated by others and it was difficult to find a comfortable cadence. Also on a long gentle decent with the wind behind I was pushed to keep up with a 42t chainring, couldn’t spin fast enough…but love it off road and obviously for CX racing
Not all cycling revolves around "go-fast" bikes. As a touring cyclist used to riding with a 42-32-22 crankset and 10 spd 40-11T cassette, it's becoming more difficult to find components that will allow me to continue to get my 40-50kgs of bike+touring gear up the hills that I can now. I know that serious unsupported bike touring is a small market, but that doesn't mean that it should be wiped out. I have triples on the rest of the fleet too, because they make riding easier. The constant marketing efforts of the manufacturers to get people to spend money on new bits that provide marginal, if any, improvements for the average cyclists just serve to lighten your wallet rather than your load!
Since the writing of this article, Classified cycling put their powershift hub on the market. It essentially does away with the front mech and chainring. I've been using one for 3 months now and my conclusion is that indeed, for gravel racing, cyclocross and high-end commuting, it's the future. All of the advantages offered by 22 or 24 gears, wireless shifting under full load, no front derailer drawbacks, no cross-chaining and closely spaced gears. Don't think it will ever win over the (wannabe) pro road riders but I'm happy.
https://classified-cycling.cc/
Unless you use a Classified rear hub, a 2x is still required for the race/performance-oriented riders. Only when we get to something like 14-speed 1x drivetrain, these roadies will have the combination of a wide enough range and close enough steps between sprockets.
For most others, 1x is now already a feasible solution, I think. We only need more cassettes that favour small steps in the middle over small steps in the beginning.
Those wide cassettes are expensive, and MTB users often trash cassettes cruising in high gear on roads, it was rare for me to be able to change a chain on a MTB without the dreaded skipping.
So it's a fair bet that most single speeders will not have even wear across the cassette, whereas roadies tend to use more of the cassette and you can get about 3 chains to one cassette with a properly maintained chain.
Some of the SRAM cassettes are eye-wateringly expensive, the days of Campag individually tailored sprockets are long gone.
I just sold my road bike and I'm using my gravel bike which is 1x on the road with a second wheelset... I gear out at about 60kmh so just tuck at that point... That said bumpy terrain descents when In top gear has seen me lose the chain.
Range is decent for gravel and road and for touring I have a surly 29er with a rohloff... Zero maintenance solution with a 500+% range
How many years of updates will it take for the article just to read "No, it isn't"
Lets face it, the future of cycling is whatever the manufacturers want to foist on us, regardless of wheter it is a step forward or back. They know the lure of the new is too strong for too many to resist
3 years ago when this story was first posted (then presumably dredged up for some hits after the writer left) it made sense to question due to SRAMs but 1x drive. Since then noone really followed for road bikes. So I think we are decided on 2x for the foreseeable future. Until marketing deems it unworthy. Look forward to seeing this story reposted next year !
Yeah, the 1x worked so well for aqua blue
I suspect this is one of the main reasons manufacturers are pushing 1x...
Rohloff is bulletproof. For touring in remote locations of for that matter in any application where it just needs to work all of the time and where speed is not a concern, it's the shiz. Huge range, reasonable spread, with the external mech if something breaks you can always put it in an 'acceptable' gear. Just (imo) a fairly long run-in period and lots of whirring when you go down to 7 or 8. And they'd have to develop a proper road handlebar shifter. On my commute bike I went with a 1x and powershift hub because I like speed and closely spaced gears. But on one occasion last winter my cassette clogged up with freezing slush and I wished I'd have taken the other bike, hoofing it to work in -5 centigrade.
And how many road.cc readers are professional or even amateur road racers?
You dont run an F1 car on the road - why does the choice of a professional race team dictate your own bike?
except 13 speed Ekar is already here and 12 speed Shimano is just around the corner. Things are always changing and it looks like 1x is here to stay.
Yes there are more 1x options for MTB, cyclocross and 'gravel'. I'm always happy to see more options. However the road bikes that I referenced? 2x not going anywhere.
I don't think the front derailleur will die anytime soon. A system without a front derailleur means that the chain has to twist more to reach the gears both on the tall and small end of the gears, this will rapidly destroy a chain probably in about 300 to 750 miles; some people I've read about on the internet get only 1000 to 2000 miles now on their chains which I think that's obsurd that a chain won't last at least as long as a tire! actually a chain should last at least twice a long as a tire...not a racing tire but a regular tire most people buy.
If the industry made some sort of plastic chain that was very cheap to buy, like $5 to $8 or so, and it lasted 300 to 750 miles then great, but otherwise forget it, they already made the chains last about 3 times LESS then the old school 5, 6, and 7 speed chains lasted, now they want to shorten the lives some more? I guess I know who else wants a piece of the rich person wallet.
I've been using 1x on my road bikes for a couple of year now. Racing, training and epic mountain rides.
The general use bike has 44f with 10-42 rear. Great range of gearing for 99% of occasions. Since I've gone to road riding from MTB, I'm comfortable with the large jumps in gearing. Never felt I need to micro-manage cadence. Changing front rings is a 5min job and I've run everything from a 40 for crazy climbs like Taiwan KOM Challenge to a 46 if I know it's going to be a fast rolling hills bunch ride.
The race bike is set up with 50f and 11-34 rear. Tighter gearing for crits and local club races. Perfect for hilly crits. Personally, I like never having the think about the front mech. And I've lost count of the number of times I've gapped people on climbs as their 2x has played up changing front rings.
I still have a bike with a 2x, but confess to very rarely riding it these days. So for me, the front mech is dead. But it's definitely not for everyone. My brother won't have a bar of it and he can't stand not riding at his perfect cadence or not being able to pedal up to 70km/h on a descent.
no way.
I can't stand cassettes with large jumps. I even miss a 20t between my 19 and 21t, ideally I'd run a 14-23 10speed or 14-25 11speed cassette with 48-39 chainrings.
The finer the increments are, the better for those who are not superb strong and sensitive to large jumps. When I have more power and muscle, I hardly notice 2t jumps, but, whenever I do not commit enough time (and calories) for developing muscle, I'm struggling with anything cruder than 1t increments.
1t-1t-1t for me please
I’ve been running 1x11 (50x11-42) for the last few months and it’s been great, obviously a bigger jump in the upper gear range but I like the simplicity and reliability.
186FD64E-0C36-46DD-95E0-E8A2BB195DD8.jpeg
I would certainly welcome a simpler gearing setup that was lower maintenence and had nice even steps between gears. I'd like a wide gear range and long durability.
I would like to see cheaper and lighter pinion gearboxes with standard bottom bracket mounting points that allow for simple swaps/upgrades between manufacturers/models and that would even allow the standard gearbox to be swapped for a motorised e-bike conversion unit.
https://www.cyclingabout.com/new-pinion-gearbox-for-2017-the-lightweight...
Pinion-Gearbox.jpg
Meh.
It'll be like the "radical' Mike Burrows Giant TCRs that ONCE used. They appeared pre-season with all sorts of tech, but by the time the races started they had all the usual kit on - not the adjustable stems, plastic-spoked wheels or adjsuatble layback seatpins.
1x would be great for a crit bike or TT bike as most riders only use one ring for those events anyway, but for a road bike for any kind of hilly race, they'll need the overall range and the small gaps between gears.
And for consumers, I'd go for it on the TT bike and probably a crit bike, even living somewhere hilly, but the price doesn't reflect the saving in complexity and materials.
I did a single ring conversion on my mtb and love it, although the 40T extender sprocket I chose was probably not low enough for me. I've never felt the need to do similar for my road bike - an 11-28 cassette with 50-34 is just enough for me to climb most hills in my area. Switching to single ring means you lose the ability to drop down (or go up) more than a couple of gears at a time. I need that for undulating terrain.
I looked at going for 1x when I built a gravel bike earlier this year, but the cost was utterly ridiculous. There was no way I could justify it.
I get the benefit for off roaders, the front mech is an obvious place for dirt so in event and general maintenance (can't spell) it makes sense to lose it if they can get the range required. Most downhillers could probably use a hub with 5 gears in it and not have a traditional chain.
If it's fit for purpose, fine. Most 'propoer' roadies that want varied terrain, cadence, smooth changes etc. wouldn't get this from 1x and don't get any of the so-called benefits either...
This is an old article, did something change?
Meanwhile, single-ring racing did not go so well for Aqua Blue...
I just don't see the point for road riding. Big gaps in the rear cassette can really ruin a ride for me, especially when you find yourself riding into a headwind or up a long, slight incline.
I have 50/34 & 14-26 on my commute bike and 52/34 & 12-29 (or 32) on my best bike. I don't see how a 1x system with even 12 speeds can replace either of those.
How much maintenance does a front mech need? In my experience it's the least troublesome part of the drivetrain.
Looks like comments have covered every opinion, but just my simple input - I have run 1 x 11 on my mountain bike for years, and it makes a huge difference, but not what was mentioned in the article. In (good) mountain biking you are constantly moving from up to down to flat in very short distances, and having to change a front and rear to cope with quick changes in terrain was a nighmare. 1 x solves this brilliantly. On a road bike this situation is amost never encountered, so question the need for a 1 x other than simplicity.
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