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All Those GearsBy Randy Boren(from the Suwannee Bicycle Gazette, Spring 2000)When someone sees a high end bike for the first time they usually ask, "How many gears does it have?" The second thing they ask is "Do you use them all?" They are amazed at the number of gears on this kinetic piece of art that we bikers treasure and twist with such enthusiasm. To the novice rider with little experience, every gear is important. But if you get hooked, and find yourself telling everyone who will listen about how many miles you rode this week, my answer to you is "no, I don’t use them all." There are a few front sprocket and rear cog combinations which cause the chain to be offset at an angle where heavy torque (strong legs) can cause chain jump, or at least put heavy stress on the chain and teeth. So for the most part, mountain bikes are kept in the middle sprocket and the ratio selected with the rear derailleur as the ride conditions vary. When you experience tailwinds and descents, use the bug front sprocket; for sugar sand or steep climbs, the inner ring puts more torque to the wheel. But when conditions return to normal, the middle sprocket is the gear to select. 90% of the time this is where you will leave the left shifter. There are several reasons this will improve your riding quality. First, the front derailleur must move the chain between gears which are 10 or more teeth different in size. This means that shifts are not as instantaneous or as smooth as shifting between the rear cogs, which are much closer together. Second, the advantage to having so many gears is to be able to fine-tune the load to the conditions in which your are pedaling. When you are cruising along comfortably and then hit a slight uphill or an increase in wind, one click with your right hand will ease the load on your legs and lungs. Don’t be afraid to experiment a little as you ride.
The wide range of ratios available will let you choose a gear for any condition. Say you are pedaling briskly at 95 revolutions per minute (rpm). If you choose 5th gear of the rear cogs and select the middle front sprocket, you will travel at 15 mph. If you pedal at the same crank speed in your lowest of low gears, you will creep along at 4 mph, but you should crawl over anything in your way. At 95 rmp in your big front ring and small rear cog, you will cook along at 28 mph. Many bikers in flat Florida can endure at 7 to 10 mph in single track, 10-15 on dirt and grass, and 15-20 mph on pavement. Watch better riders and notice how fast they pedal, then pick a gear to match them. Make it a habit to shift down two clicks with your right hand every time you approach an obstacle before you have to use the brake. This way, when you reach the turn or ditch, you will already be in the proper gear to accelerate effortlessly away. No need to strain, just start pedaling and within a few seconds you will be ready to shift back up to your previous cruising gear. Practice shifting just before you use the brake and soon you’ll feel like you have an automatic transmission. Your bike will seem to always be in the right gear. By changing gears frequently, you will be able to adapt any change in terrain you encounter. A headwind won’t mean more work, just more time to look at the scenery. Your ride buddies will notice you keep up with less effort and you will have more breath to talk as you ride. You’ll start to see more of the sights before you call it a day because you won’t be as sore or tired. And when some one notices your fancy bike, you will smile knowingly as they ask about all those gears!
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You can find a gear which maximizes your
endurance by balancing the load between your legs and your lungs. If you are out of breath
and your legs don’t hurt, you are pedaling in a gear that is too low (you are
spinning too fast). If your legs are tired but you are hardly breaking a sweat, the gear
you are using is too high. To ease your legs, make a habit of using a gear which makes you
pedal a little bit faster. In any event, always try to find a gear which has you turning
the crank at just over two to three stokes per second. That’s 11 to 16 full
revolutions in ten seconds or about 65 to 95 rpm. At these pedal speeds, you will balance
the load on your legs and your lungs like a pro. 