What is cyclocross?
A “pure” cyclocross bike is designed for cyclocross races, although as we’ll see below many cyclocross – or cross or CX – bikes are specified so that they can be used for activities other than racing.
A cyclocross race takes place on a closed off-road circuit which is predominantly on grass, tracks or sand and will contain obstacles such as low barriers, sand pits, steps or steep banks. Usually some of these obstacles will require dismounting from the bike, carrying it, then remounting – all of which require specific techniques. Most races last less than an hour.
Cyclocross races used to take place predominantly in the winter months, so mud was a major feature, with the bikes churning up the circuit. Now there are more summer races too, such as the London Summer Series which takes place in July and August.
As well as amateur races, there are professional competitions, which take place mainly in Holland and Belgium and are keenly followed, drawing large crowds. The elite riders tend to be cyclocross specialists racing for cyclocross-specific teams although a few road racing pros also participate.
There’s a piece here by Ian Field, the current and four-time British champion, on how to get into cyclocross racing.
So what’s different about the bike?
A cyclocross bike is built a bit differently from a standard road bike and we’ll go through the different features below. But the overall appearance is more chunky and usually there’s less of a height difference between the saddle and the bars. Lower priced cyclocross bikes are typically made of aluminium while the pricier models have carbon frames. The majority will come with a carbon fork.
To ensure grip in off-road conditions, a cyclocross bike will be fitted with wide tyres. The UCI, world cycling’s governing body, uses a formula which usually limits tyre width to 33mm for competitions, but many cyclocross bikes are sold with 35mm tyres for extra grip and stability.
Tread patterns differ dependent on the conditions on the course. Hard or sandy conditions are usually tackled on file treaded tyres, as low rolling resistance is more important than grip. Once it starts to get wet or muddy, tyres with knobs come into their own, with the knob size and tread pattern increasing as the conditions become more sketchy to add more grip and mud-shedding capability.
Many cross bikes come with clincher tyres, although professionals and more serious amateurs typically ride on treaded tubulars which can be run at lower pressures for more grip. Tubeless clincher tyres are also beginning to appear, which have the advantages of tubulars but are easier to set up and provide puncture resistance too.
Tyre pressure is critical to off-road handling with pros often riding tyres at below 30psi. This is easier with tubular or tubeless clincher tyres, neither of which is susceptible to pinch flats. For a standard clincher set-up a pressure nearer 40psi provides a bit more protection from bottoming out the tyre on the rim, which can cause pinch flats.
Mud is almost inevitable in cross races and cyclocross bikes are built with plenty of clearance between the tyres and the frame so that the wheels keep turning even when it collects on the bike during the race. This is evident around the forks, the chainstays and the seatstays and there’s also more space between the rear tyre and the seat tube and bottom bracket than on a road bike.
In 2013 the UCI permitted the use of disc brakes on cyclocross bikes used in competition. Now the majority of cross bikes are sold with discs. Lower end bikes will have mechanical disc brakes, although full-hydraulic systems are becoming more and more prevalent as component manufacturers offer more options. It’s also possible to use a converter like Hope’s V-Twin, which sits below the stem to allow the use of hydraulic disc brakes with cable-actuated levers.
Previously, cyclocross bikes used cantilever rim brakes for their mud clearance. Many cyclocross pros still use them in competition and a few cyclocross bikes and frames are sold with cantilever brakes or with additional mounts for cantilevers as well as disc brakes.
Disc brakes provide quicker and more consistent braking and it is easier to modulate them to get the correct amount of stopping power than for cantilevers. To handle the stresses on the wheels from disc brakes, cyclocross bikes are increasingly being specified with thru axles. These are borrowed from mountain bikes and result in a more rigid wheel to frame connection than a quick release. They may be used at the front only or for both axles. Rear axle spacing is usually 135mm but bikes with 142mm axles are appearing too. Thru axles also help improve accuracy of disc placement in the brake calipers.
A typical cyclocross bike designed for competition will come with a 46/36t double chainset and a fairly wide range cassette, which may be switched out dependent on the circuit and conditions. Although this gives quite a low top ratio for road riding, which would result in spinning-out, it should give enough top-end speed for most cyclocross courses. Less cross-specific bikes may be kitted out with a compact double with 50/34t chainrings.
Another trend is the increasing use of SRAM’s 1x (pronounced One-By) transmission. This dispenses with the second chainring in favour of a much wider spread of sprockets in the cassette, so that the number of gears drops from 22 to 11 but the available range remains similar. The chainring has alternating wide and narrow teeth to mesh better with the wide and narrow links in the chain, helping to clear mud and prevent chain drop. The rear derailleur too has a unique design with a clutch to prevent chain slap.
Another feature of many cyclocross bikes is the routing of the gear and rear brake cables, which are typically fully enclosed and run along the top of the top tube to keep the mud at bay, although internal and down tube routing is also found. This helps to protect the cables in poor conditions and makes it more comfortable when carrying the bike on your shoulder during a race.
The more subtle difference from a road bike is in frame geometry. There’s typically a longer wheelbase for increased stability off-road and to build in the necessary clearances. The frame angles are slightly less acute which also helps with handling and there’s a shorter top tube. This results in a more upright riding position than on a road bike, which along with the more level bars and saddle allow the rider to shift their weight around more easily to tackle obstacles and to control traction.
Since there are usually unrideable obstacles on cross race courses, competitors will dismount and carry their bike before remounting. This may be easier with a slightly lower saddle than you would ride on a road bike. Cyclocross frames typically have a flattened top tube to make running with the bike on your shoulder a bit more comfortable.
Our pick of the best cyclocross bikes
Pedals and shoes
Quick mounting and dismounting and running in mud and sand with your bike require different pedals and shoes from sitting on a road bike. Cyclocross bikes are usually set up with clipless mountain bike pedals and riders use shoes which will take two bolt style cleats and which have grips and sometimes studs. These may be mountain bike shoes but there are an increasing number of cyclocross-specific shoes becoming available too.
And what other things are cyclocross bikes good for?
Being robust, ruggedized and with lots of clearance and stability, cyclocross bikes are increasingly popular for other activities. They make good commuter bikes and many come with mounts for mudguards and racks, so that they can also be used as winter bikes or for touring. Many top-level cyclocross bikes used to come without bottle cage mounts, since there isn’t any need to drink during an hour-long race, but cage bolts are now pretty much the norm.
The place of cyclocross bikes as do-it-all road bikes which can also tackle bridlepaths and off-road sections is gradually being usurped by the newer category of adventure road and gravel bikes, which have many similarities but more on-road oomph and off-road stability. Many manufacturers are now adding such adventure road and gravel bikes to their ranges.