KISS — Keep It Simple, Stupid. There’s a lot to be said for simplicity, and one way to make a bike’s transmission simpler is to ditch the usual pair of chainrings and get by with just one.
A few years ago this would have been unthinkable. The unquestioned way to get a wide range of gears on road bikes was to have at least two chainrings. It’s generally a good idea for gear ratios to be fairly closely spaced. An eight- or nine-speed cassette and two chainrings gave you two overlapping ranges of reasonably closely spaced gears. When you ran out at the high end of the small chainring or the low end of the big ring, you just changed chainring and maybe changed a sprocket or two as well to get to the next higher or lower gear.
It’s taken the bike industry a while to catch on, but the development of 11-speed cassettes changed things substantially. You can now have 11 reasonably closely-spaced gear ratios with just one chainring. You save the cost and complexity of a double chainring, front derailleur and shifter, and it’s one less thing to think about as you ride.
Single-chainring systems are now very common on mountain bikes, where they're known as 1X (say "one by", as in 1X10, 1X11 and even 1X12). That’s driven development of the technology that has now spilled over to drop-bar bikes. Mountain bike designers had extra incentives to ditch the front mech; getting rid means no longer having to design a suspension system around it. You can put your suspension pivot where you like, and it’s also easier to accommodate fatter tyres if you don’t also have to find room for two or three chainrings between the frame and the crank arm.
So far, most the spillover of single chainring systems to drop-bar bikes has been for cyclocross racing. Cyclocrossers have been using single-ring set-ups for decades, because if you’re going slowly enough to need the low gears of a small chainring, you should probably be running. Single chainrings with teeth designed to keep the chain in place have helped make this more popular; some previous cyclocross single-ring systems used a pair of chain guards to keep the chain on. Effective, but hardly elegant.
Gravel/adventure riding is another genre where single chainrings have traction, for the same reasons of simplicity that make them popular on mountain bikes. However, at the moment you could argue that single-ring transmissions have a small problem with limited gear range for riding that often involves very steep climbs or luggage. Hubs with SRAM’s XD freehub body help solve this problem by allowing a ten-tooth smallest sprocket and we wouldn’t be surprised to see a version of SRAM’s Eagle 12-speed, 10-50 cassette for gravel bikes soon. If you’re looking at a bike with SRAM’s 11-speed 10-42 cassette and want lower gears, you can always fit a smaller chainring and coast on steeper descents.
Speaking of SRAM, most of the bikes here have SRAM transmissions. Shimano was slow to get on the single-ring mountain bike bandwagon and doesn’t currently make a single-ring version of any of its road bike transmissions. That means bike manufacturers have a choice of phoning up SRAM and ordering a complete set of parts or bodging something together. It’s not surprising they choose SRAM.
Is a single-ring set-up right for you?
Like all new developments in bikes, single-chainring systems divide opinion. Among the road.cc editorial team, for example, road.cc founder Dave Atkinson has enthusiastically embraced 1X and does most of his riding on a single ring. He says: "There are plenty of good reasons to run a 1X setup. For a start there's no front mech, and front mechs are a faff. They jam up easily because of their mounting position, they rub on the chain and they drop the chain or push it over the top of the big chainring if they're not perfectly set up. You don't get any of those problems with a single ring, and a thick-thin chainring never, ever drops the chain, in my experience. Ever.
"Secondly, gearing becomes rational, simple and logical. Too hard? Change up. Go faster? Change down. There's none of the psychological baggage that comes with swapping chainrings and no having to adjust your gear at the rear too when you do. And there's one less gear cable to look after as well. They're quieter, too: no chain slap because of the clutch (or stronger spring) in the mech, no movement of the chain on the chainring and no rubbing of the front mech plates.
"I've been running a single ring transmission on my main bike, a Kinesis Tripster ATR, for a couple of years now, and I'm sold on on it as a great general purpose setup. It'll depend on what you use your bike for, but for an everyday machine they're great."
On the other hand, technical editor Mat Brett is a sceptic. He acknowledges the simplicity of 1X and the way you can't get chain rub on a front mech that's not there, but says: "You get some gert big jumps in gear ratios across such a wide-range cassette. In a typical set-up, the 38-tooth chainring and 42-tooth sprocket give you a 24.3in gear while the next largest sprocket is 36-tooth and gives you a 28.3in gear. It can be difficult to keep your rhythm when swapping from one to the other.
"That said, the 42-tooth sprocket will get you up nearly anything – not necessarily quickly, but at least you'll keep progressing.
"At the other end of the scale, I find myself running out of gears on long, fast descents. If you want to pedal at over 28mph you have to spin at more than 100rpm in an 11-tooth sprocket. If you want to pedal at over 33mph you're looking at 120rpm, so I find myself just coasting more often than usual. If you're going to ride only on tarmac and unladen you might find many 1X systems under-geared."
Let’s take a look at some single-chainring bikes.We've listed the gear range for each one, in gear inches based on a 27-inch wheel. That's about the rolling diameter of an ETRTO 584mm (650B) wheel with a fat tyre or an ETRTO 622mm (700C) wheel with a 32mm tyre. A change of tyres will change the gearing, but these numbers provide a basis for comparison of gear ranges between bikes.
The Mason Bokeh is a highly capable adventure bike with a feature-packed aluminium frame, splendid aesthetics, and handling that ensures it's as at home on the road as it is on the trail.
The Bokeh combines an aluminium frame and carbon fork with all the key ingredients of an adventure bike, including wide tyres, disc brakes, thru-axles, relaxed geometry and mounts for mudguards and racks. The Bokeh goes the extra mile with a front dynamo mount, third bottle cage mount, 700C and 650B wheel size compatibility and fully internal cable routing.
You can have all Mason's bikes with 1X gearing, and the set-up Mason has chosen here is as versatiled as it gets.The wide-range SRAM 10-42 cassette paired to the 42-tooth chainring up front will get you up and down most climbs and descents without unduly running out of ratios.
Gear range: 27-113 inches
The is the only off-the-peg Shimano-equipped bike here, and Specialized makes it work by exploiting the compatibility between road bike and mountain bike Di2 shifting. Specialized has paired an XTR Di2 rear derailleur from Shimano’s mountain bike line with Shimano R785 Di2 hydraulic brake/shift levers to drive an 11-40 XTR cassette. An Easton carbon chainset carries a 40-tooth chainring.
The Diverge is one of our favourite bikes of recent years, and this luxury edition is no exception. Dave Arthur described it as “one of the best adventure bikes I've ridden” and added: “It's a sophisticated ride with buckets of capability for going fast and tackling big journeys over varied and challenging terrain.” It’s not exactly cheap though.
Gear range: 27-98 inches
One of the most exciting road bikes around, 3T's Strada is the only single-chainring aero road bike available, and while its tight clearances and inability to run a double chainset might put some people off, those issues fade away when you ride it. It's a truly stunning bike with breathtaking speed, impressive smoothness and fine handling balance.
Gear range: up to you
Stick knobbly tyres on a road bike and you get an indifferent off-roader, at best. But put slicks on a mountain bike and it'll blat along on the road perfectly well. With that in mind, Merida based their Silex bikes on mountain bike geometry and – to a certain extent – riding position, and the result is a belting all-rounder that's lots of fun off-road.
Gear range: 26-98 inches
This is the carbon fibre version of a bike we reviewed and really liked in 2017, and in going composite it's shed a couple of kilos of weight, which is impressive. We expect the Hook EXT-C to be as big a bundle of fun as its steel cousin, but less work on climbs and on the road. Trail riding is where the Hook EXT really excels though, thanks to huge 2.2-inch ETRTO 584mm (650B) tyres.
Gear range: 26–98 inches
All four of Specialized’s Crux cyclocross bikes now have singe chainrings, and this one is a simply brilliant crosser that provides really good handling, bags of pace and all the benefits that disc brakes bring to the party, all wrapped up in a bold looking package. It's ready to race, but is equally at home blasting along bridleways and through the local woods for a couple of hours.
Gear range: 34–98 inches
Trek's Crockett is mostly a race-ready cyclocross bike, but features like the clever Stranglehold rear dropout and relatively tall head tube make it more than a one-trick pony.
Gear range: 34–98 inches
The SuperX has a stellar frame, with a smooth, stable ride that's perfect for flatter cyclocross courses and playing in the trails. You'll probably want to upgrade the wheels though; they're a bit beefy. While you're at it, get wheels with a SRAM XD freehub if you fancy wider-range gearing.
This is the 2019 model. If you can live without the snazzy paint job, 2018 bikes are still available in 54cm and 56cm frames for just £1,749.99.
Gear range: 34–98 inches
Whyte's Wessex is a longstanding road.cc favourite. Here it's configured as perhaps the ultimate fast day-ride bike for dirt roads and neglected, frost-ravaged back lanes. Racing aside, it's all the bike you really need for year-round riding in the UK, fast enough for sportives and pacy training runs, comfortable and reliable for grinding out winter miles, and at home on longer commutes. Only a British company could design a bike that is absolutely, perfectly, 100 per cent suited to the demands of year-round UK road cycling.
Gear range: 28–119 inches
The two-bike Cortina range is aimed squarely at the privateer weekend cyclocross racer. Fortunately, what goes into making a decent cyclocross bike can – sometimes – make for a decent road and gravel-adventure bike. This is one of those times. The Cortina's handling is exemplary. Testing the AX1 in the winter, our Mike Stead snagged number two spot on a Strava descent, bested only by a mountain biker the previous summer. It'll take mudguards and racks too, and out of the box the gearing is suitable for almost everything but racing.
Gear range: 24–103 inches
The gravel/adventure thing may have softened some cyclocross bikes a touch to make them more versatile but Boardman's CXR 9.4 is having none of it."Ready to race straight out of the box," it says on Boardman's website and while it could do with a couple of minor tweaks the CXR 9.4 is one flickable, lightweight off-road rocket which is an absolute blast on the technical stuff.
Gear range: 30-93 inches
Very much a bike for high-speed playing in the trails, the cyclocross-derived Toughroad GX SLR 0 has a light aluminium frame, tubeless wheels and proper dirt-road tyres in its 40mm Giant CrossCut Gravel 2s. There are rack mounts too, so if you want to load up and disappear into the distance you have the choice of bikepacking bags or panniers.
Gear range: 26–98 inches
With its carbon fibre frame, 45mm tyres and massive selection of gear mounting points, Kona's new Libre platform is billed as "the ultimate adventure machine' and for once it looks like that hype is justified. Sensibly, Kona have gone for hubs with SRAM’s XD freehub body, allowing a ten-tooth smallest sprocket so the 40-tooth chainring still provides a decent high gear, and it'll still be reasonable if you decide to fit a 36-tooth ring for hauling gear. There plenty of rack and mudguard mounts, four bottle mounts, a top-tube bag mount and Salsa-style three-bolt rack mounts on the fork legs.
Bit spendy for you? Its steel stablemate, the Rove ST, has many of the same features for just £1,499.
Gear range: 26-108 inches
The RUUT AL is an aluminium gravel/adventure bike from Polish brand Rondo. It’s a super comfortable multi-surface machine with agile handling that can be adjusted between fast and racy to more upright and relaxed through its cleverly designed, geometry adjusting Twintip fork. The 43mm Panaracer Gravel King tyres work well in all but silly conditions, and there's scope for 55mm ETRTO 584mm (650B) tyres and wheels if you want to go even fatter.
The RUUT distinguishing feature is that fork, which has swappable 'chips' in the tips that change the offset and ride height. The difference is not that noticeable at the handlebars as it’s only 1cm in height difference, but turning into switchbacks and barrelling along the singletrack, the difference in steering feel is noticeable. In the low axle position with the longer trail, the bike needs more input to take the same lines as the high axle position with the shorter trail. It's a clever feature, letting you choose the handling that you like best for your own trails and style.
Gear range: 26–98 inches
As the name implies, this is an endurance road bike with adventure tendencies, the only one of BMC's Roadmachine family to dispense with the traditional double chainset. By the standards of many of the bikes here it has skinny tyres at 34mm, indicating its purpose is more Tarmac than trails, but with a wide, low gear range it looks well suited to long days in the hills.
Gear range: 26-98 inches
The Polygon Bend CT5 is a rough and tough 'urban sport' bike that offers loads of versatility. It's not the lightest bike out there but it'll handle everything from all-weather commuting to gravel tracks, and it's a lot of fun. It offers a fairly upright riding position and a decent level of comfort, largely thanks to 30mm-wide Schwalbe G-One Speed tyres, and it's easy to fit mudguards and racks.
The Bend CT5 really shows its worth over poorly surfaced roads. It doesn't just cope with randomly-varying crummy road surfaces, it eats them up, giving you the confidence to tackle the next section that bit quicker and generally putting a smile on your face.
Gear range: 24–93 inches
Drop-bar bikes with ETRTO 584mm (650B) tyres are still quite rare, but Vitus chosen the smaller and arguably more versatile wheel size here, and built it in carbon fibre to keep the weight down. With hydraulic disc brakes, 1x groupset and full-carbon fork, this Substance CRX holds plenty of appeal for the modern day on/off-roader.
Gear range: 26–108 inches
Whyte is also clearly a believer in the 650B concept too, enough to call the Glencoe " the best all round road bike we have ever made". But like the Merida Silex it shows strong signs of Whyte's expertise in mountain bikes, with a long frame, short stem and wide bar for control on crummy surfaces. The 47mm tyres put the Glencoe in the RoadPLUS category, Marin says and we've certainly been impressed by the capabilities of the WTB Horizon tyres Whyte has chosen. If you're looking for something a bit out of the ordinary, the Glencoe deserves close examination.
Gear range: 28–108 inches
The Energie VR is an excellent tool for thrashing round in the mud for an hour on a Sunday, and it's versatile enough for more general riding. The drivetrain is excellent and it's tubeless-ready out of the box. For the money, it's hard to fault. It's built around a 6061-T6 triple-butted hydroformed aluminium alloy frame that's mated to a full carbon fork, and both of those are tidily built. The bike has mounts for a rack and full mudguards and two sets of bottle bosses, so it's properly versatile if you want to run it as a winter bike/adventure bike/tourer.
Gear range: 30–98 inches
With its wide, flared bar, the Sonder Camino from outdoor equipment specialists Alpkit is very much at the 'off-road adventure' station on the liine spectrum from pothole-basher to intercontinental expedition. This is a bike that enjoys going off-road but would also be quite happy taking you longer distances on tarmac too. The bias – and the way the bike is specced certainly corroborates this – is towards off-road adventuring. The comfortable position is perfect for gravel excursions or riding long distances loaded with luggage, but is just a little too upright for longer (proper) road rides. It’s a do anything bike with a definite off-road flavour, but above all, it’s a bike to have fun with at a price that belies its capabilities.
Gear range: 26–98 inches
Evans Cycles rightly describes the Arkose as being "a gravel bike before we were using the term". The 2019 Arkose line has been revamped with more tyre clearance, and a range of builds for different purposes, some for predominantly road riding, some for dirt and the X, which is a true do-everything bike. It has SRAM's Rival 1 transmission and hydraulic disc brakes, with 650B wheels shod with WTB's 47mm 'road plus' Byway tyres.
Gear range: 27–103 inches
Chris Boardman has always said that his cyclocross bikes are his favourites in the range. With a big gear range, SRAM Apex hydraulic discs, and mounts for racks and mudguards, the CXR 8.9 exemplifies the versatility Boardman loves about cyclocross bikes, and it's outstanding value for money.
Gear range: 28-108 inches
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Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.
Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.
Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.
The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.