“XC” or Cross Country cycling is a test of physical endurance and technical ability. Riders race on specialized “XC” or Cross Country bikes.
But what is it that makes an XC mountain bike an XC mountain bike?
The short answer: an XC bike is a mountain bike specifically designed for speed and stability over long distances.
For the long answer, you’ll need to understand what XC racing is, how XC bikes are specialized for this type of racing, and how each part of an XC mountain bike is designed for performance in races.
In this article we’ll cover:
- What Is XC Cycling?
- What Is A Cross Country Bike?
- 8 Key Elements Of An XC Mountain Bike Explained
- Choosing The Right XC Bike For You
Ready for the full lowdown on all things XC mountain bike?
Let’s dive in!
What Is XC Cycling?
Cross country mountain biking involves racing long distances over rough terrain. It’s the only mountain biking event at the Olympics.
Unlike Downhill biking, which involves maintaining control while performing difficult maneuvers while hurtling down a mountain, XC Biking is mostly a test of speed and physical endurance – at the Olympics, events are designed to take around 90 minutes.
In this way, Cross Country cycling combines the endurance test of road cycling racing with the skills-based test of navigating difficult terrain in mountain biking.
Cross Country cycling involves racing along single-track, which is a trail wide enough for a single bike to pass along.
Single-track trail races run through forests, rough rocky terrain, and sometimes along fire roads.
Cross country trails are easier than more difficult mountain biking trails, as the sport is more centered on physical endurance than technical challenge – though in recent years there’s been a trend for XC courses to become increasingly difficult.
What Is A Cross Country Bike?
As speed is the priority in cross country races, XC bikes are the lightest type of mountain bike.
To manage the bumps and drops of cross country courses, XC bikes’ suspensions generally have around 120mm of travel. This is less than downhill or enduro bikes which require more.
Full-suspension cross country bikes have both front and rear suspension, while hardtails only have a suspension fork at the front.
The shape of a cross country bike seats the rider in more of an upright position than a road bike, which makes it a little more stable on downhill trails.
However, XC bikes seat riders less upright than downhill bikes, which allows for better climbing, handling, and agility.
8 Key Elements of an XC Mountain Bike Explained
So now you have a general picture of an XC Mountain Bike, let’s get into the details!
As mentioned, XC Mountain Bike frames are light – typically between 7.5-12.5 kg.
Frame geometry is fairly flat these days as XC trails have gotten tougher, meaning XC Bike frames have to more closely resemble trail and enduro bike frames.
XC bikes will have a long wheelbase (distance between Front and Back wheels) to increase stability:
- A slack head angle and long front-center will sit the front wheel further in front of the rider’s hands and prevent the bike from pitching forwards on downhill sections.
- A long rear-center places the rear wheel further back to compensate for this and creates a naturally more even weight distribution, which is good for cornering.
A slack head angle also increases the bike’s stability at speed by creating more trail in the steering.
Trail helps produce a force that aligns the front wheel with the direction of travel – which is known as the Caster Effect.
XC Bikes will have comparatively low bottom brackets to give the bike a low center of gravity for increased stability. However, bikes with longer suspension travel will have higher bottom brackets to prevent pedals from clipping the ground.
#2. Saddle & Seat Post
The seat post angle is fairly steep to better place the rider squarely over the bottom bracket and allow for more efficient pedaling into the chain.
The steep angle also helps to prevent the bike from pitching backward as the rider’s center of gravity shifts during climbs.
Some riders like to use dropper posts, which allow them to instantly drop the saddle into the seatpost.
This is helpful for big drops, or for getting low on turns. It’s generally triggered by a button on the handlebars which drops the saddle, and then returns it using a pump or spring – high-end electronic dropper posts are also now available.
In the past, XC handlebars were narrow – but nowadays they are wider, often 760mm and above for more technical downhills.
XC handlebars come in aluminum or carbon fiber if you’re looking to keep weight down.
They’re also pretty flat, with minimal rise and upsweep which you’d see on other mountain bikes because XC riders need to place their weight forwards and minimise bend in the wrist which will become exhausting over long trails.
XC bike stems are shorter than those on road bikes, though not as short as the tiny stems of downhill bikes. A short stem makes going downhill easier by making pitching forwards less likely.
#4. Disc Brakes
For all types of mountain biking, disc brakes are essential for a safe and comfortable downhill experience.
This is because disk brakes are able to apply more stopping power from a more gentle hand-activated brake. They are also modular, which means you can easily apply braking to the degree required.
Also, in mountain biking, protecting your kit from the tough conditions is important.
Finally, disc brakes work on any tire size, no matter how wide, because there is not a caliper mounted to the wheel’s rim – meaning you can cycle on large, thick tires which are increasingly popular in XC biking.
#5. Wheels & Tires
Large wheels ride better on the bumpy or soft terrain you’re likely to find on an XC trail – so large 29-inch wheels are now standard for XC bikes.
Large wheels also create more trail, which makes the bike more stable at speed due to the Caster Effect.
Large wheels will also reduce the chance of “tucking under” – when the wheel is pushed away from the direction of travel, such as when you hit a bump.
These days XC tires are fairly thick – Olympians often compete on 2-inch treads.
Some XC riders will fit different treads to their front and rear wheels, as grip must be prioritized at the front, while punctures and rolling resistance are considerations for the back.
As mentioned, XC bikes will either be “hardtails,” only fitted with a front suspension fork, which are lighter and cheaper, and best suited to climbing and speed in general.
Or, they can be “full-suspension”, which means they have a front suspension fork as well as rear suspension. These are a little more expensive, are stronger on the downhill sections, and will be more comfortable over long races and trails.
At the Tokyo 2020 Games, nearly every athlete cycled on full-suspension XC bikes.
Good suspension is important as it allows you to pedal more efficiently over uneven terrain.
XC bikes’ slack head angle slightly decreases the effectiveness of the front suspension fork, so a good amount of travel is needed to compensate for this.
Though they can be tricky at first, many XC riders choose to use clipless pedals. Clipless pedals offer security on rocky terrain by reducing the risk of your foot falling off the pedal, which can cause accidents at speed.
The gold standard for clipless mountain biking pedals (and corresponding cleats) is the Shimano SPDs.
Mountain biking clipless pedals need to be mud resistant – so minimalist cleats are beneficial.
Some also have a platform or cage to protect the pedal mechanism from bashes it may take from rocks and roots on trails.
However, some riders prefer flat pedals as seamlessly shifting your foot on and off the pedal can be helpful on tight corners.
Most flat pedals have pins that allow your mountain bike shoe to grip the pedal through rubber soles.
They are typically made with metal, although higher-end pedals might be made of resin and will be lighter.
#8. Gearset & Chain
XC bikes should have wide-range cassettes for versatility across downhill stretches and lung-busting climbs.
Cranksets generally have one a single chainring at the front, though some have two chainrings.
Since the introduction of 1×11 and 1×12 groups, first with SRAM in 2012, single chainrings at the front have become the norm – these chainrings will feature ‘stepped’ teeth and will not be fitted with a front derailleur.
Chain security is also a priority as the bumps and bounces of an XC trail can cause dropped chains.
Mountain bikes have specially designed mountain bike derailleurs, often fitted with clutches, which maintain enough tension to prevent bumps from causing a dropped chain.
Choosing The Right XC Bike For You
XC mountain biking is tough, there’s no question about it.
But if the physical challenge of attacking rough trails at speed appeals to you, you deserve to find the right bike to do it.
Hopefully, this guide has given you a better understanding of what makes an XC bike an XC bike – and you’ll be able to take this information out onto the trails!