Dirtbike riders will often...
Dirtbike riders will often take the exact opposite of what streetbike riders would consider a conventional line to take advantage of a berm. here, everything is optimized: braking uphill, turning on positive camber, and accelerating downhill. The gains in corner speed offset the added distance enough that motocross riders will go yards out of their way to utilize even a small berm.
Ask any rider to point to the most difficult corner of a particular racetrack or twisty road, and it will probably be an off-camber or downhill corner. Devious racetrack designers purposely incorporate elevation and camber into their tracks to increase the level of difficulty, while on the street natural terrain and even the standard construction characteristics of a roadway can lead to areas of tricky camber and elevation. Knowing how those features affect the way your bike reacts, however, can reduce your anxiety when you are confronted with an off-camber corner, and can help you use certain features to your advantage on both the street and track.
Camber refers to a difference in height between the two edges of the road or track, creating an angled surface that you must ride across. A banked turn, such as those found at a superspeedway, is considered to have positive camber; an “off-camber” or negative-camber corner refers to a turn where the outside edge of the pavement is lower than the inside edge. Changes in elevation are often referred to as slope; positive slope indicates you are riding uphill, with negative slope indicating downhill.
In a banked turn, such as...
In a banked turn, such as the bowl turn at the Streets of Willow shown here, a tight entry line will allow you to turn on the banked portion of the corner rather than on the flat, Note that the rider ahead in the picture shown here taking a wider entry will not only have to turn earlier—on the less-banked portion of the turn—but will also be braking downhill on the banking, negating some of the benefits of the camber.
The physics work in your favor with positive camber, as you probably know (hopefully from experience rather than watching NASCAR). A banked turn is much easier to ride than an off-camber turn because you don’t need as much lean angle relative to the pavement for a given speed. Alternately, you can go faster for a given lean angle. Likewise, braking is easier done uphill than down, while accelerating is easier downhill than up — gravity works in your favor in both cases.
In turns with either camber or slope in play, you can adjust your line to take advantage of those characteristics. Here, we can take a cue from dirtbike riders, who will go way out of their way to take advantage of even the tiniest berm — positive camber — on a motocross or supercross track. Likewise, you can adjust your line in a corner so that you turn on the most banked part of the corner and avoid the off-camber portion. On turns with elevation changes, brake and enter on the portion with as much slope as possible, and accelerate on the part with the least. Keep in mind, however, that there will be a tradeoff in some situations as you may have to travel more distance. Again, take a look at how far dirtbike riders will vary from a conventional line to use a berm for an indication of how much camber and slope can help you.
Here is one tricky bit to think about: Slope and camber are not separate, and interact depending on your line in a particular turn. For example, consider riding on the left-hand side of a road that is steeply cambered, with the high part of the road to your left. If you change your lane position to the right-hand side of the road, you will be going downhill — across the camber — adding a slope component to the forces acting on your bike. This must be taken into consideration when you are experimenting to find the optimum line in a particular corner. Racetracks are often deceptive when it comes to slope and camber, and this is another instance where walking the track can be a benefit, allowing you to closely look at various sections. GPS data can help also, as it includes altitude, from which you can calculate slope.
The standard camber on a roadway...
The standard camber on a roadway leads to many left-hand turns being off-camber. In this instance, a wide entry with a late apex and tight exit is not only the safest line but it also allows you to minimize the effects of the camber.
On the street, the camber built into a road generally gives right-hand turns a slight banking. On racetracks, you may find a corner that is banked throughout. A conventional wide entry may seem best as the camber is consistent throughout the turn, but note that you will have to brake downhill — across the track — to enter the turn, which offsets some of the camber. In this case, a tight entry not only provides you the most camber for your turn, but is also a shorter distance. A left-hand corner on the street is generally off-camber for the same reason. Here, or with off-camber corners on the racetrack, a wide entry with a late apex will allow you to brake and enter uphill (across the camber of the lane), offsetting some of the negative camber to your favor.
On many racetracks, corners are nestled at the bottom of a hill or just at the crest, providing the most challenge as both camber and slope change through the turn. Adjust your line as necessary so that, if possible, you are braking and entering on a portion with positive slope. Try to accomplish the bulk of your actual turning on the most cambered portion of the corner. Again, keep in mind the distance travelled, which will play a part in how much time you are saving, and don’t be afraid to experiment. You may find something against convention and your intuition that works to your advantage. SR