Cornering on Dirt – Three steps to better cornering for mountain bike and cyclocross riders
By Coach Martin Baker
With cyclocross and short-track mountain biking increasing in popularity, many riders new to off-road riding are entering races relatively unfamiliar with cornering on dirt, mud, and other slippery surfaces. (Snow and ice, anyone?) Some come from a road background, while some come with no experience in a competitive, high-performance cycling environment. What they have in common is being uncomfortable with the sensation of bicycle tires moving around and sliding under them. This is quite understandable, because those who have experienced tire slid, or “drift,” on the road, probably recognize it as that feeling they had right before they crashed. Road tires don’t like to slide, and when they do, a crash is almost a given. New dirt racers may also have difficulty selecting the best line through a slippery corner or be unwilling to try new lines as the course evolves during a race. And they can find using the brakes effectively on a slippery surface to be daunting. For many riders, this adds up to tentative cornering, slow exit speeds, and wasted energy re-accelerating out of the corner.
The Braking Zone
Generally when braking in cyclocross, all that is required is to scrub off some speed as you approach the corner, so don’t over-brake. On a mountain bike, you may well need a more aggressive application of the brakes. In either case, apply the brakes progressively and try to feel what’s happening through your hands. The goal is to get most of your braking done before turning in to the corner. If you do still need to brake after you enter the corner, feather your rear brake but stay off the front brake. The front brake provides around 75% of your braking power, but this can be a double edged sword when grip is limited. Locking the front wheel will likely cause the front to wash out, resulting in a crash. If it’s slippery and you’re turning when you lock the front, a crash is almost a certainty. Developing good feel for your brakes is an important skill, one that all riders who excel in slippery conditions share.
When the riding surface is smooth and consistent grip-wise, the line through a corner will usually be the same: swing out wide prior to entry, turn in and dive towards the apex of the corner, and again swing out wide to carry speed through the exit. In practice however, bumps, obstacles, and varying grip levels will require the rider to modify the “ideal” line. If it’s bumpy, rocky or rutted and you are on a ‘cross bike, you may have no choice but to look for a smoother line. If you are on a full-suspension mountain bike, you will have much more ability to ride over that kind of thing. If it’s muddy and slippery from traffic, look to the outside for grass or vegetation (or fresher snow!) that might provide some grip. Early in the race, it is common for the best line to become choked with riders, sometimes even coming to a standstill. In that case, explore any line that’s open – even if it’s significantly longer, it is likely to be faster. If the outside of the corner has some banking to it, as on a motocross track, you may be able to fly around the outside without touching the brakes and carrying more speed than the shorter inside line.
Positioning on the bike
As you approach the corner, you want to have a low, aggressive position, either in the drops or on the hoods (if on a cross bike) and with elbows bent. Inside pedal should be up with your knee pointing into the turn. Your eyes should be up and looking where you want the bike to go. Press your foot into the outside pedal to help keep the tires loaded. Thus far, none of this is much different than aggressive cornering on the road. Where it is different is in the lean-angle of the bike. Cornering off-road usually requires the bike to be leaned at a greater angle to be able to engage the outside row of cornering knobs. But on the dirt, you can’t just lean your body further to the inside of the turn as you would on the pavement – you must lean the bike in under your body and keep your body more to the outside of the turn. Here’s another way to think of it: Picture a rider on the road in mid-corner coming towards you. If you draw a straight line from their bottom bracket to the top of their head, it will pass through their top tube, or very close to it. But that same line drawn on an off-road rider will not pass through the top tube – the top tube will be further to the inside of the turn because the rider is keeping their body and center of mass more upright and to the outside. Why is this? In addition to helping you engage the cornering knobs, you are more stable. If the tire slips or moves around on a loose surface and your center of mass is leaned way into the corner, it is unlikely that you will be able to recover. If the bike is leaned in, but your center of mass is less so, a slip of the tire can be caught. Keeping your center of mass outside can also help in quick transitions, allowing you to flick the bike back and forth more easily for fast riding on twisty single track. Mastering this technique will make the new off-road rider more confident on slippery or loose surfaces and make them far more comfortable with the feeling of their tires moving around. Give it a try on your mountain bike, cross bike, or even your road bike – the difference is quite apparent – and you will be gaining speed and confidence in no time!
Coach Martin Baker works with all levels of road and mtb racers and specializes in bike handling on the dirt.