Descending a Hill

Eli Post

This article originally appeared in July 2009 WheelPeople. The images were added, and the ride suggestions still apply. Bob Zogg and John Allen helped edit the original article.


Some sports thrive because they offer an opportunity to experience the exhilaration that comes from meeting danger face-to-face. In this regard, skydiving comes to mind. Cycling, on the other hand, is more serene, except when descending a mountain road at high speed. If you are a professional racer, you realize that you must master the descents to be a contender. You learn how to position yourself, how to lean in a turn, how to brake and when not to brake, and even how to crash to avoid broken bones. Carving turns at 60 mph in a pack takes practice, and requires guts.


For ordinary mortals like us, however, the challenge is to deal with descents we typically encounter on hilly rides in New England. For some, a descent full of twists and turns is nothing short of bliss, while for others it’s pure terror. Wherever you fit in this spectrum, you may find helpful some instruction on how to handle unforeseen problems.


Steep descents can be tricky. Steering will be exaggerated, small turns become more difficult, and your weight is transferred forward. This is a very different experience from riding the flats, and you must know how to counteract these forces. In addition, the road surface conditions play a greater role. At slow speeds, potholes, gravel, spilled oil, and fallen tree limbs are a challenge, but at high speeds such conditions can become a greater threat.


If unfamiliar with steep downhill riding, travel cautiously and avoid attempts at speed records. As descents are a learning experience, only gradually let your speed increase as you become more competent.


Bike Maintenance. If the brakes work poorly, if the spokes are loose, if the tires are badly worn, or if the frame or fork is out of alignment, the bike should not be used at high speeds. In fact, the bike shouldn't be ridden at all until repaired.


Body Position. When descending, move your hips back on the saddle, lightly squeezing the nose of the saddle between your thighs. Distribute your weight between the saddle and the pedals, and keep the crank arms horizontal (i.e., one foot forward, one foot back). If you have drop handlebars, use the lower position and a relaxed grip, prepared to brake. Relax your whole body so that you can absorb road shocks with your legs and arms.


Braking. Speed control on descents is essential, which is best accomplished by feathering, or light taps, of the brakes. Stopping distances increase greatly with speed (especially when the rims are wet!). The brakes on a bike cannot stop you as quickly as those on a car, so it’s important not to follow too closely other riders or cars when descending. The steeper the descent, the less hard you can brake without pitching over the handlebars, so choose a speed that will allow you to stop comfortably if there is an obstacle or hazard just out of sight. Another problem in descending steeply is that the wheel rims and brake pads may get hot if you apply them too frequently or for too long a time, potentially causing tires and tubes to fail. Use both brakes and short intervals of braking with time in between for the rims to cool. Look for relatively level spots where heavy braking can be used to reduce speed. Brake before cornering. On a tandem, you’ll want a drag brake - a large drum brake or disc brake - to avoid overheating from rim brakes on long descents.


Road Position. Watch farther ahead than usual and anticipate dangers. Pass other riders carefully, leaving additional clearance. Use your brakes to keep a safe distance behind riders you can’t pass. When riding at high speeds, move to the center of the travel lane to give yourself more leeway to avoid road hazards, and to discourage motorists from passing you within the travel lane.


Speed Wobble (AKA, Shimmy). Some bicycles can develop a dangerous front-end shimmy at high speeds. This is more common on a bicycle with a less-rigid frame or a suspension front fork. A good technique to bring the bike under control if it starts to shimmy is to press one or both knees against the top tube. Brake gently, as rapid braking can worsen the shimmy. Push both hands forward against the handlebars, without attempting to fight the shimmy.


Road Hazards. When traveling downhill at high speed, a hole, loose sand or gravel, or a slick section of road, can be dangerous. Even the slightest jog can make the bike difficult to control or trigger a shimmy (if your bike is prone to shimmy). If you are unable to maneuver around a pothole or other obstacle, unweight your tires, or even jump your bike, just before you ride over it. Practice this move on a grassy field. Level your pedals, crouch off the saddle, then spring up and lift with your feet and hands. Start by jumping over a line on the ground, then graduate to higher but forgiving objects such as a rolled-up towel. This technique works best if you use clipless pedals, or toe clips and straps.


Cornering. When cornering, lean your bike while keeping your body more upright. Weighting your outer pedal and/or pointing your inside knee into the turn can help you maintain proper cornering position. An abrupt steering correction can break the front tire loose, as can the front brake if applied with too much force. Ride within your limits, and adjust your speed based on your line of sight.


Gaining Confidence. On hills that you ride regularly, try each time to apply the brakes a little less to gain confidence. By using the techniques discussed above, you'll probably find that, with time, you can maintain comfort and safety at higher speeds.


In what must be ironic coincidence, we had valuable feedback before this article was published. A reviewer of an early draft was on a ride shortly after he read the draft, read it in sufficient depth so that he provided very useful comments. His ride took him on a descent on Lost Lake Road in Groton, and as he was equipped with a GPS we know that he was traveling at 34 mph just before it happened. A truck with a jet ski in tow was backing out into the street. The vehicle was on the rider’s right, and to increase his margin of safety, he turned left and braked. The bike started to shimmy, the “vibration turned to uncontrollable oscillation of the handlebars”, the tube blew, and the front tire came off the rim, although not necessarily in that order.



He went down, and while he was bruised, we are thankful that he was not seriously injured, and was able to ride the next day with the author of this article. My friend reported that in the moments before the impact he made very quick judgments about emergency maneuvers. The “judgments were close to instinctive reaction”, and he “remembered none of the suggestions in the draft article.” He does not recall precisely his grip or how quickly he turned or how hard he braked. This does not surprise us, as we do not expect to convey expertise in one reading. You need to do more than read an article to prepare yourself for emergencies such as this. However we do hope that you continue to think about these hints and riding practices and build them in to your riding routine. Eventually they will become second nature.




Photo by Mary Kernan taken in Saguaro National Park