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Sunday, November 15, 2009

Descending 101


A past issue of Cicloturismo, sister magazine to Bicisport, featured a 4-step program by Paolo Alberati for improving your descending skills. For most of us, these skills are difficult to practice simply because there aren’t many twisty descents where we live. During our tours we’re reluctant to offer too many suggestions, fearing a client will try them and end up in the weeds or worse, the hospital! Here are some CycleItalia tips based on Cicloturismo’s suggestions.

Before you crest the pass, clear your head of extraneous thoughts, take a drink and give your brakes a squeeze to make sure they’ll respond when needed.
Assume the proper position – hands on the bar “drops” with a finger (or two) extended towards the brake levers. A CycleItalia tip: If you can’t easily reach a brake lever with your index finger while holding the bar with your other digits, back off the brake adjustment so you can hold the lever in a bit with one finger without actually applying the brake. With modern braking systems you’ll still have plenty of lever travel for maximum braking while needing to do nothing but pull in your index finger to actuate the brake while maintaining a secure grip on the bars. Flex your arms to absorb road shocks.
Plan a smooth trajectory around the curve. Use your brakes before you lean into the turn. Use both brakes together. Enter the turn from the widest point of the road – this is of course easier when the road bends to the left, be careful about using both lanes, especially on right hand bends.
Avoid a bike too light. As American Andy Hampsten used to say, “the only thing worse than not having a super-light bike for climbing is HAVING one for descending!” Many superlight bikes are super-stiff or super flexy, neither is good for fast, sure, fun descending.
Look where you WANT to go. Don’t get distracted by potholes, gravel or patches of bad pavement and end up running right into them. Your eyes should follow the path you want to take while your peripheral vision watches for anything that might cause you to deviate from your chosen path. Constantly remind yourself to look far down the road, especially at high speed. If you look at the road just in front of you, it’s too late to do much about a pothole because you’re already about to hit it. Seeing it early enough to avoid it is the key.
Separate your braking and cornering actions. Your tires provide your only points of contact, called contact patches, with the road. Each tiny patch must contend with braking and cornering forces, but each has only so much traction (grip) on the road surface. If you’re using all the available traction for braking, for example, adding any cornering force will simply overwhelm the traction and the tire will start to slide. Same thing with cornering—if you’re leaned over and putting all the traction to use in cornering, adding braking forces can overwhelm the traction -- and down you go. Highly skilled riders can blend these forces, gradually releasing the brakes as they lean into a corner or vice-versa, still using the maximum grip available but not exceeding it.

Use a reasonable tire pressure. If you’ve watched auto or motorcycle racing on TV, you’ve probably heard about tire air pressure being used to “tune” the vehicles for the track conditions. They often use the lowest tire pressure they can get away with since maximum traction and grip in the corners are their goals. Cyclists of course must contend with rolling resistance but this is vastly overrated. Tire ads hype the “advantage” of saving 30 seconds in a 25 mile time trial--truly meaningless to most of us. But the cornering capability of a tire at 100 psi vs 130 psi or more IS significant, especially when you consider the tire is almost all you have for any suspension. Once you have enough air pressure to prevent a “pinch flat” in most conditions, additional air pressure does little except reduce the traction the tire can provide. The last thing you need is a tire so hard that it bounces through a corner instead of tracks smoothly, absorbing the road’s irregularities. A larger section tire, with it’s increased air volume, can be run at a lower pressure, provide a smoother ride AND superior traction---exactly why you see Grand Prix motorcycles with huge racing slicks. With bicycles and wheels getting stiffer and more unyielding all the time, some of the major bike tire makers have begun to offer high-performance tires with larger sections in an effort to soften up the harsh ride.

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