Downhill mountain biking - everything you need to know
Downhill riders relish all those features that most other mountain bikers avoid: half-a-story drop-offs and doubles. No other form of mountain biking provides a similarly testing environment for equipment and component durability. In a single downhill run of a few minutes, riders will subject tyres, suspension components, rims, and frames to more impact loading than a cross-country rider might endure in a month's training.
If it works (read: ‘survives’) in downhill mountain biking, it should last forever for average trail riders. That is why carbon fibre components are only considered broadly trustworthy once professional downhill mountain bikers are willing to use them.
Equipment and gear
In downhill mountain biking, grams don’t matter. The ‘gravity racing’ epithet rings very true for downhill mountain biking, which means that durability is the higher principle – never weight.
The frames, whether aluminium or carbon, feature radical geometry, and oversized tube sections. Seat tube lengths and angles are irrelevant for pedalling, with downhill mountain bike designers prioritising shock placement and rear-suspension movement. The seated rider position is purely incidental, although downhill-specific saddles are a thing and used not for sitting, but as a steering influence, with riders applying pressure with the inside thigh.
Downhill mountain bikes are slacker than any other off-road riding frames, pushing the limits of fork construction and bushing bind. It is not unusual to see downhill mountain bikes with head angles at 62 degrees, which is a lot slacker than a trail bike at 67 degrees.
The suspension components are oversized, with much longer forks (200mm and beyond), featuring 40mm stanchions. Again, much longer and larger than your average trail mountain bike, which runs a 140mm fork with 34mm stanchions.
Most downhill mountain bike frames also feature a coil shock, which is proven to give the best bump sensitivity and is more robust. On a long downhill track, where air shocks risk overheating, coil shocks remain consistent in their performance. If you get a landing wrong and overload the bike’s rear on impact, a coil shock is more likely to survive than an air damper with more sensitive internals and seals, which can blow.
Downhill mountain bikers have twice the suspension travel of a conventional cross-country mountain bike and much fewer gears (7-speed versus 12-speed). Brakes are much more powerful too, with rotors up to 220mm and four-piston callipers being the standard.
The downhill mountain bike market was a long-standing purveyor of the smaller, 650b wheel size, and many riders, especially those on small or medium frames, still prefer smaller wheel sizes for their agility and stability in the air. But in recent years, as first found on the Santa Cruz V10 29 prototype in 2017, the larger 29" wheel size is now standard across the field.
Clothing and protection
Safety trumps all when downhill mountain bikers choose their riding kit. The best full-face helmets are the go-to options, with some brands offering carbon-fibre reinforced structures to reduce weight.
Due to its additional mass, many newbie downhill mountain bikers struggle with the sensation of a full-face helmet, and the industry has invested in making these helmets lighter and more breathable. At a price.
The other personal protective equipment you’ll see on downhill mountain bikers are the best mountain bike kneepads, to guard against rock strikes, under armour and neck braces.
Downhill mountain bikers rarely ride with conventional cycling eyewear, preferring goggles. Shoes are another clear differentiator. You won’t see downhill mountain bikers riding super stiff carbon-soled shoes. Flexibility soles are preferable, allowing riders to ‘feel’ more trail feedback through the pedals.
Softer shoes with oversized uppers allow for better strategic impact protection around the toe box. And when you overshoot that tight switchback corner and need to push back up, it’s much easier to do in a soft mountain biking shoe with natural walking dynamics.
It is worth touching on the peculiar attitude of aero and downhill mountain biking. All the least aerodynamic principles are present with downhill mountain bikers: peak visors on helmets, baggy clothing, and enormously wide handlebars. Of those three things, two are necessary: the peak visors are a crash impact feature, and wide handlebars give more leverage and steering stability when landing jumps or pinging through rock gardens.
But the baggy clothing? That’s purely a style statement. The one element in downhill mountain biking where style is the higher principle above performance.
During the late 1990s and early 2000s, downhill mountain bikers rode in skinsuits, which were judged aesthetically at odds with the projected image of extreme riding but were banned due to their aero performance. Since then, baggy gear has been the default, although experimental data has proven that a skinsuit will benefit professional-grade downhill mountain bike riders by a winning margin, on a race run. Although, we're beginning to see riders sport tighter, slim fit baggy clothing.
Super steep trails
Downhill mountain biking does exactly what it says: there’s no pedalling uphill, it’s all about the gravity descent. Unlike enduro mountain biking, which can require some explanation, downhill riding and racing are probably the easiest for non-riders to understand.
The most important requirement for a downhill trail, or track, is steepness. All great downhill mountain biking trails share a common theme of topography – they are way too steep to ride up.
On a proper downhill track, you should never be required to pedal anywhere during the descent and you should be on the brakes in most places to control your speed. In terms of risk certification, downhill trails rank higher than any other, primarily as black, or double black diamond. That means there are unavoidable features of consequence, which cannot be rolled if you lack the skill or confidence to ride them.
Some qualifying features that make a downhill track so demanding are jumps, drop-offs and set-ups. All those trail features require the confidence to compress and launch a mountain bike and the appropriate posture to keep it stable while airborne, to deliver that safe landing.
A general rule on downhill trails is that you might encounter jumping distances and drop-off heights, which edge towards and into double-digit numbers when measured in feet.
If downhill trails are so steep and extreme, how do riders get to the top of them without being completely exhausted? Especially when downhill bikes are virtually impossible to pedal uphill? Well, most of the world’s best downhill trails are counter-seasonal winter snowsport venues, which means a reliable chairlift or gondola is at your service.
Racing against the clock and yourself
Group dynamics define most competitive off-road cycling. Unlike road cycling, the time trial is a rarity off-road but downhill racing is the exception, where riders get the whole track to themselves.
All downhill mountain biking events are effectively time trials. When the start gate drops or the timing marshal taps your shoulder, no other riders are on track to compete with you. It is a simple race to the timing beams at the bottom.
With its large jumps, daunting rock gardens, and drop-offs, most downhill racing courses can look intimidating for novices. So, how do newbies safely enter and progress into the downhill racing scene? Flow trails are part of the answer.
Some bike parks contain downhill trails that have all the steepness without those intimidating rocks, roots and the option of B-lines around the jumps and drops. This is a great way to experience the thrill of getting ‘counted down' at the start gate without the anxiety of venturing into a trail with features you aren’t comfortable with.
Despite lacking the natural alpine terrain of France or the western corner of North America, the UK has possibly the world’s best-developed downhill riding community. All age groups and genders are strongly represented at UK downhill racing events, and although mud is a reality, the slick organisational skills and sense of community compensate.
Although timing slips and spreadsheets are integral to downhill mountain biking and ranking competitiveness, weekend warriors should approach it differently. For most riders, downhill mountain biking is a race against themselves; to conquer new features and master the more technical aspects of trail descending.
Building confidence towards clearing that double or landing a drop-off is the true appeal of downhill mountain biking. Not finding a few seconds on a deeply technical trail.
Some of the best downhill mountain biking experiences are a weekend of repeat runs, down a great trail, with like-minded riders. And that can be in the Alps, during your summer vacation, or a weekend in Wales, at a local bike park.