Throughout my 20+ years of teaching clinical molecular imaging, the reference point I referred my students to most often was, “Remember your basics.” Well yes, riding a bicycle is not molecular science, but the basics are still a great place to start for learning the appropriate science of gravity and motion. Balance is the essence of riding a bicycle.
Beginning cyclists, Newbies, frequently find themselves stressing-out with processing the dynamics of riding with cars and other cyclists, shifting gears, and navigating hills and curves. While riding seems complicated at first, as our skills increase we focus less on the many details of driving a bike and have increasing time for actually enjoying the scenery and the ride.
#1 on the list of ‘basics’ is that balancing is really the essence of riding a bike. Some first-time riders just jump on their bicycle and go. For others, children and adults as well, the first attempt is a fearful and wobbly event that is repeated many times before balance is achieved and freedom arrives. With experience we learn to just think “lean” or “turn” and our subconscious makes it happen automatically. By repeating the correct skill over and over the neural pathways in our subconscious become established and eliminate much of the stress along our learning curve.
A bike tends to balance itself in a straight line and at speed, movement of the front wheel is very slight and relative to front end geometry. Choosing the right bike starts with the rake of the fork and its trail. OK, do not get blurry-eyed over this terminology. You can take ownership of front end geometry-no molecules involved here, just a smidgeon of math. While shopping for a new or used bike start with the degree of angle of the head tube. Bikes intended for racing will have a steep head tube angle, such as 74 or 75 degrees and a corresponding steep angle of the seat tube. These factors determine the length of the chain stays and overall wheel base. The sharper the angles, the shorter the chain stays-the faster the rear wheel follows the front wheel around a turn. This also means you must pay some additional attention to where your feet are relative to the front wheel as you make turns. The more shallow angles of a touring bike head tube and seat tube are in the 71-73 degree range. This will increase the length of the chain stays and increase the overall length and wheelbase, while increasing stability and comfort. If you extend a line through the head tube and fork all the way to the ground and measure back to the point at which the tire touches the road, you have measured the ‘trail’. Bikes with steeper angles are intended for racing by more experienced cyclists. Longer wheelbase bikes are more comfortable, more stable, and better suited for distributing the weight of loaded panniers and casual riding. Racing bikes are also built for minimal tire clearance and 700Cx23 mm tires will definitely add to the “twitchiness” of steep geometry. Although wider tires increase road resistance, they also increase comfort and balance. Now that you understand front end geometry, keeping in mind that the best bike is a bike that fits you, the stand-over height is the primary factor. Bicycles, even of the same model, may not reflect the same geometry from a small to a large frame.
Guided by its front end geometry, a bike does not follow an absolutely straight line. It steers itself in an almost imperceptible weave as it self corrects for slight changes in front tire drag. If you push a bike by itself, it will maintain a straight line and stay upright until the forward momentum ends. In keeping with this concept, if you were to lock the front end to prevent it from steering itself the bike would quickly capsize. The bicycle does a constant little dance that repeats over and over as it self corrects for slight changes in front tire drag and returns to vertical. As we can see, balance is already automatic. All we need to do is “become one with our bike, Grasshopper.”
#2 on my list of basics is steering. OK, with balance the bike wants to return to vertical. With steering the bike wants to return to a straight line. Now, get ready for some more terminology! When steering into a curve the bike must first be rolled into an angle where gravity will balance with “centrifugal force” and allow the bike to follow a steady arc. This is actually not a force, but the tendency of objects wanting to return to a straight line when forced into a curving path. This process is initiated by momentarily pointing the wheel away from the direction you want to turn. This is termed “counter steering. While correcting for almost imperceptible changes of the front wheel can be controlled from the nose of your saddle, big changes of direction are controlled by pressing down on the left or right side of the handlebar. The amount of pressure you exert on one side of the handlebars determines how far into the roll you will go to that direction. By pressing in the other direction you may make corrections so you maintain the smooth arc of a curve or turn. Just remember to press down on the inside to roll down and press on the outside to roll up. As this pressing feeling becomes more and more automatic, you will become part of your machine. The better you understand this sequence, the more likely you will practice the correct cornering skills. How much pressure is needed to hold your intended line will vary with differences in front end geometry.
#3 on my list of basics is the art of making a U-turn. No need to get blurry-eyed on Newton's law of universal gravitation, which is written as a vector equationto account for the direction of the gravitational force as well as its magnitude. ……just wanted to see if you are still with me!
U-turns seem intimidating to new cyclists, as well as to many experienced cyclists. Sooner or later you will need to make a U-turn. On the first occasion where embarrassment overcomes fear, every cyclist is forced to take that giant leap-of-faith. Sir Isaac Newton may have had to deal with the embarrassment of dismounting his bicycle in order to turn around while composing his laws of classical mechanics. Forget about calculating your vectors, U-turns are no more rocket science than are balancing and steering. Simply stated, the farther over a bike leans, the tighter the radius of turn. The pedal on the turn-side should be up, to avoid digging-in for a spill. With the outside pedal down, load you weight on that pedal and press down with your hand on the inside handlebar. At slow speed forward thrust becomes primary in keeping your balance. If you experience the feeling that you will fall over, apply more thrust. If your turn-side foot is about to make contact with the front wheel, a series of short back-pedals will enable you to maintain thrust incrementally throughout the circle.
Our brains think both consciously and subconsciously. For skills to become automatic the subconscious aspects of our brains must develop the proper habits of bike control. Cycling safety increases when our minds are not focused on details of balance and steering so we may be in the moment regarding what is happening around the corner or over the hill. Our skills are either improving or degrading. If you want to improve, practice whatever you find difficult. While you are warmed up at the end of a ride, practice a few U-turns. Remember, a smile always helps the wheels turn.