How to Use Gears (speeds)

Most bicycle manufacturers seem to believe that their models are purchased exclusively by male athletes aged under 25 years. As part of this fantasy, stock bicycles are equipped with gears that are often much too high for the average mature man or woman. (The phrases “high gear” and “low gear” will be used repeatedly, so let me define them once again. A high gear is one where it is hard to pedal uphill, and a low gear is one where it is easier to pedal uphill.)

Despite having 18-24 speeds, touring and mountain bikes may still be geared too high to match the pedaling style of the average middle-aged rider. On road bikes the climbing gears are also frequently too high, and their range is too narrow, to permit many mature adults to maintain a pedaling cadence of 60 - 90 RPM.

At this writing, many bicycle shop salespeople are just beginning to understand the needs of bicyclists of both sexes who are more than 25 years old. They are learning not to deride gears lower and more powerful than those the manufacturer provides as “granny gears.” And they are beginning to discover the varied options that are often available to enhance the performance of older riders. Frequently, a specific model can be ordered with a choice of crankarm lengths; with a choice of chainring sizes and shapes; and almost invariably with a choice of freewheel cogs. Each of these variables can have a dramatic effect on your bicycling performance.

If these options are not available, you can usually negotiate to have the desired changes made without extra charge when you purchase a new bike. Almost always the bike shop will make the required changes on the spot in order to close the sale, or the parts can be ordered and the changes made within a few days.

Even if you have an older bike, vast improvements in gearing can often be made very inexpensively by simply changing two or three cogs on the freewheel.

Gears

Never forget that the right bike is the one that lets you spin the pedals at a cadence of 60-90 r.p.m. or more. If you find pedaling uphill hard, the most likely explanation is that the bicycle you are riding has climbing gears that are too high.

Switching to a wider range of gears can do more to enhance your bicycling performance than any other single step. To maximize your performance — to conquer hills and headwinds — your bicycle must have a gear range wide enough to permit you to adjust your pace smoothly and accurately to a wide variety of conditions and terrain.

All too many adults are riding with an inadequate range of gears because they didn’t know what to ask for when they bought their bikes. They just accepted the gears the bike came with. And many bikes sold to people in their 40s have gears that are better suited to a 20-year-old.

Bicycle Gears Made Simple

Understanding bicycle gears becomes much simpler when you understand the meaning of two terms: speed and development.

• Speed. This term, as employed in the phrase “14-speed bicycle,” is used in the same way as in “a car with a 4-speed transmission.” In the car you can place the gearshift lever in 4 different forward speed positions. Likewise, on a 14-speed bicycle you can place the gear-shift levers into 14 different positions or “speeds.”

However, the actual gearing you get in each “speed” position depends on the sizes of the chainrings and cogs with which the bicycle is equipped. A 14-speed racing bicycle can have a very narrow range of gears while a 14-speed touring bike will have a much wider range of gears. Yet both bikes have the same number of speeds.

Taking it a step further, in some cases a 24-speed bike can have a narrower range of gears than a 10-speed — all depending on the number of teeth in the chainrings and cogs with which the bike is equipped.

• Development. The development of any chainring-cog combination is a number that tells you how high or how low that gear is. (As you will recall, a high gear is one in which it is difficult to pedal uphill while a low gear is one in which it is easy to pedal uphill.)

For example, a gear combination with a development of 21” (a low gear) allows you to pedal uphill with much greater ease than does a gear combination with a development of 90” (a high gear).

In everyday conversation, many bicyclists use the word gear rather than development. They’ll say, “I was riding in my thirty inch gear.” But what they really mean is a 30” development.

It’s essential to master the concept of development at this stage, because understanding development numbers is the only way to tell how low or how high any particular gear combination is.

Ask the average bicyclist what gear he is in and he’ll probably reply, “I’m in my forty-two, twenty-one,” indicating that the rider is using a 42T chainring and a 21T cog. This usage is fairly common among racers because almost all racing bikes have fairly standard 52T—42T chainrings and cogs in the 13T-23T range. Thus most racers will have some idea of whether this is a big, small, or medium gear.

But when someone says, “I was riding in my thirty-eight, nine teen,” to be perfectly frank it doesn’t signify much more to me than it probably does to you. Is this combination higher or lower than being in a twenty-four, thirty-two? Or is it higher or lower than, say, a forty-six, thirteen? Which of these 3 combinations has the greatest hill-climbing power? Or which would be best for a long downhill run?

For an accurate answer, you must know the development of each of these combinations.

What, then, is development? Any combination of chainring and cog sizes creates a development that is measured in inches. To calculate the development of any chainring-cog combination, you simply multiply the gear ratio by the diameter of the rear wheel in inches. The gear ratio is obtained by dividing the number of teeth on the chainring by the number of teeth on the rear cog.

Let’s say you’re using a 42-tooth (42T) chainring and a 21T cog (42 divided by 21 equals 2). That’s a ratio of 2:1 or two-to-one. Your rear wheel is 27” in diameter. When we multiply 27 by 2 we get 54”, which is the development of this particular combination.

In practice, you don’t have to do any calculating to figure out the development of any gear combination. Table 3.1A provides gear developments for 27” wheels and Table 3.1B does the same for 26” wheels. For 700 wheels, use the 27” table.

Assuming you have a 38T chainring and a 19T cog, entering Table 3.1A with these coordinates shows the development as 54” (38 divided by 19 multiplied by 27 equals 54).

Why do these two different combinations have the same development, you may wonder? How can a 42T x 21T combination, and a 38T x 19T combination, both have a development of 54”?

Interestingly, at least half a dozen other common gear combinations all have the same 54” development when used with a 27” wheel. (Examples: 36T x 18T; 40T x 20T; 44T x 22T; 46T x 23T; 48T x 24T; and 52T x 26T.) And the reason, of course, is that they all have a ratio of two to one.

But when one rider says, “I’m in my forty-eight, twenty-four,” while another says, “I’m in my thirty-six, eighteen,” you’d never know that both are riding in the same gear. Whereas if each identified his chainring-cog combination by its development, they would both say, “I’m in my fifty-four inch development.”

It doesn’t matter what combination is being used to provide a 54” development. When someone mentions a 54” development, you immediately know it’s the gear most adults choose when riding on the level against a light breeze.

An experienced bicycle tourist in his or her mid-forties will use the following developments when riding in each of the conditions named:

• 21”: climbing very steep grades

• 25”: climbing steep or long hills

• 35”: cycling up easier slopes

• 45”: cycling on the level against a headwind

• 55”: cycling on the level against a light breeze

• 65”: cycling on the level

• 75”: cycling on the level with a breeze at one’s back

• 85”: cycling on a moderate downgrade or with a wind at one’s back

• 95”: cycling downhill or with a strong wind at one’s back

3.1A--Gear Development Chart for 27” Wheels

31B--Gear Development Chart for 26” Wheels

Developments not shown above may be calculated thus:

Development = (Number of teeth in chainring / Number of teeth in cog) x Diameter of rear wheel in inches

More About Development

The concept of gear development dates from the days of the high wheeler. Because its high front wheel revolves once for every one revolution of the pedals, a high wheeler has a fixed ratio of 1:1. Hence if its front wheel is 54” in diameter, it has a development of 54”. And the pressure you place on the pedals to make one revolution on the high wheeler is exactly the same as that required for one revolution of the pedals on a modern bicycle using a 54” development.

To make it clearer, the work and effort required to pedal a bicycle in a 54” development is exactly the same whether you’re riding a 52T x 26T combination, or a 36T x 18T, or a high wheeler with a wheel 54” in diameter.

The reason why some bicyclists keep referring to meaningless combinations is that they are unaware that gear combinations are compared by their development in inches.

There are other benefits to describing your gear combination in inches of development. It helps you to understand why it takes exactly half as much work and effort per revolution of the pedals to climb a hill in a 22” development as it does to climb it in a 44” development.

You can understand development more easily when you consider it as analogous to walking a mile with big versus little steps. Biking in a high development (or a high gear) is like walking a mile with big steps — it takes a lot of effort. Biking in a low development (or low gear) is like walking the same mile taking little steps—it takes less effort and is much easier, although it will probably take longer.

When a development is multiplied by pi (3.141), the result is the distance that the bicycle moves forward at each revolution of the cranks. In a 54” development, a road bike covers a distance of 170”. By comparison, using a 27” development, the bike would cover only 85”.

Assuming it requires 50 foot-pounds of work to rotate the cranks one revolution in the 54” development, disregarding friction, it would take 25 foot-pounds to rotate the cranks once in the 27” development.

In either development, 50 foot-pounds must be expended to cover 170 inches. But in the 27” development, you would exert only half the pressure on the pedals, making pedaling much easier, while stress on the knee is only half that when riding in the bigger 54” development.

You Need Never Walk Up a Hill Again

Call that 27” development a “granny” gear if you like. But if you use it, your knees may be in much better shape by the time you’re a grandparent than if you strain up hills in the big 54” development.

Although cycling is a non-impact sport, riding uphill in a high development like 54” (or even 44”) can exacerbate chondromalacia, or wearing away of the cartilage on the underside of the kneecap (see Section 10). Yet the lowest gear development on many racing bikes is 47”. That’s partly because racers stand up on the pedals to climb hills. Yet standing up on the pedals is too strenuous for most mature adults to maintain for very long.

Most of us sit down to ride up hills. And even a 44” development is too high for climbing most hills when seated in the saddle.

The Best Gears of Your Life

Hark back a moment to the list of developments and the conditions each is used for. They ranged from a low of 21” to a high of 95”.

As you can see from the list, the 21” or 25” developments are much more suitable for climbing long, steep hills than are developments in the forties.

And unless you’re hell-bent on speed, a high gear of 95” is more than adequate for most mature adults. At the lower end of the gear range, you’ll find that most mature and experienced bicycle tourists will have a low gear of 25”. Others go as low as 21” or even 19”.

Though they may not often use these powerful hill-climbing gears, mature riders very wisely recognize that it is far better to have a couple of ultra-low gears they seldom need than not to have a really low gear when they need it.

Again, if you’re able to jump on a road bike and take off up a mountain road, your personal gearing needs will be different. But if you’re like most mature adults — fit and active but not a super- athlete — you can still bicycle up that same mountain if you use a lower gear development. You will pedal more revolutions. It may take a little longer, and your speed will be slower. But you will indeed get up that mountain road without walking.

In fact, you can bicycle up almost any hill — even hills in Colorado that are 40 miles in length — provided you have a range of gear developments that permits you to choose a pedaling rhythm you can stay with. For many older adults as well as many younger riders, that translates into a low climbing gear development in the 21—31” range—and with a strong preference for the 21” end.

Now let’s take a look at other components that make up the drive train.

The Drive Train

Derailleurs and Shifting Levers

A pair of levers called shifters or gearshift levers operate the derailleurs. The left lever operates the front derailleur, placing the chain on one of the bicycle’s two or three chainrings. The right lever moves the rear derailleur, placing the chain on one of the five to eight freewheel cogs. To make this happen you must continue pedaling throughout a gearshift. In choosing which gear lever to use, change the chainring (left lever) first and then make finer adjustments with the right lever to the cog (see section in this guide called “Mastering the Basics”).

Since it’s considered sportier to have the shifters on the down- tube, that’s where you’ll find them on most racing and sports bikes. On all-terrain bikes each lever is mounted separately, one on each side of the handlebar, and you can shift gears at the flick of a thumb. In fact, you can change both front and rear derailleurs simultaneously.

Shifters are also sometimes placed on the stem, or at the tips of the handlebars, or they may be actuated by handlebar twist grips. Most experienced riders prefer the downtube or handlebar positions. On road bikes each lever has to be moved separately, one at a time.

Until fairly recently all gear shifting was based on friction. To shift gear you moved the lever to direct the derailleur onto the cog or chainring you wanted. Then you adjusted it manually to run quietly and smoothly. The lever remained held in that position by friction. Each lever had a screw for adjusting its friction.

Nowadays the uncertainty of shifting the rear derailleur has been eliminated by indexed shifting. Indexed shifters let you click into exactly the right preset position. By simply listening for the click that accompanies each shift, you automatically find the exact cog position. Many beginners liken it to tuning a push-button car radio. Thus indexed shifting has become standard on the rear derailleur of most modern bikes.

Indexed click shifters have obvious advantages, especially for racing or off-road riding where fast and accurate shifting is required. Yet they were mainly developed for beginners, and many experienced riders prefer to stay with friction shifting.

One reason is that gear settings are quite crucial. As cables stretch and cogs wear, indexed shifting may need adjustment. All it takes, usually, is a turn or two on a barrel screw. But not every rider has the mechanical aptitude to do this.

Nonetheless, given the choice between click or friction shifting, I’d always opt for indexed shifting.

The Crankset

Most medium-quality bicycles have Japanese cranksets. (A crankset consists of two or three toothed gears near the pedals, called chainrings or chainwheels, along with the axle between the pedals, and the crank arms connecting the pedals to the axle.) Racing and sports bicycles usually have standard double 42T—52T or 42T—53T chainrings while touring and all-terrain bikes have triple cranksets. (A double crankset has two chainrings; a triple crankset has three.) A typical touring bike crankset will have 26T-44T-50T chainrings or possibly 26T-42T-46T. Standard on mountain bikes are chainrings with 28T—38T-48T or, preferably, 26T-36T-46T.

Since most bike shops carry small 24T and 26T chainrings in stock, these chainring sets can be easily changed to 26T-38T-48T or 24T-36T-46T, or any other desired combination. Usually this can be done without extra charge at the time of purchase. In other words, you usually don’t have to accept the exact chainrings with which your bicycle is equipped at the factory.

If you plan to climb very steep grades on a mountain bike, you should investigate the Mountain Tamer Quad. It consists of an ultra-small chainring of 15T—19T that bolts on the inside of a triple crankset. This fourth chainring is normally used only on mountain bikes and is currently becoming available at mountain biking centers in Colorado and elsewhere.

Elliptical Chainrings

Chainrings can be either round or elliptical. Out-of-round chainrings have an elliptical computer-designed shape that perfectly matches the dynamics of leg movement for improved efficiency and pedaling power. The ellipse is very slight and difficult to detect with the naked eye. Currently one of the best elliptical cranksets is the Deore II Biopace HP made by Shimano. Nowadays, however, just about all Japanese cranksets are rigid, lightweight, and super- strong.

My experience, with elliptical chainrings suggests that, during part of the pedal revolution, they provide the equivalent of being in a gear one step lower than the gear you are actually in. Thus they are clearly more effective, especially on hills. Since there is almost no price difference between round and elliptical chainrings, I strongly recommend an out-of-round (elliptical) crankset. The only drawback is that the smallest elliptical chainring has 26T versus 24T for cranksets with round chainrings.

Both round and elliptical cranksets offer a choice of crankarm length. Most brands come in the shorter 170 mm length and the longer 175 mm length. Some makers also supply very short 165 mm crankarms, an intermediate 172.5 mm length, and a long 180 mm length. However, these uncommon lengths are not always available.

Longer Crankarms

Naturally, the longer 175 mm crankarm provides greater leverage and more power when climbing hills. Depending on the gearing, using the 175 mm length can be equivalent to being in a gear one step lower than would be the case if using the 170 mm length.

Since most models can be ordered with crankarms of either length, I’d normally opt for the 175 mm crankarms if you are at least 5’6” in height and your bicycle’s bottom bracket is sufficiently high to provide adequate clearance when cornering. (The bottom bracket is the short round tube holding the axle between the pedals, and to which both the seat tube and the down tube are attached.) If you are taller and there is adequate clearance, I’d certainly consider using 180 mm crankarms provided they are available. Most mountain bikes have bottom bracket clearance sufficiently high to permit the use of longer crankarms.

In any case I’d also consult the bike shop owner, or an experienced salesperson, for his or her opinion. Shorter men, and especially shorter women, should probably stay with 170 mm or 172.5 mm crankarms. And very short people will probably prefer a 165 mm crankarm (usually available only for road bikes).

Together, longer crankarms plus elliptical chainrings can con tribute appreciably to your hill-climbing ability. But longer crank- arms are not advised for shorter people because they can distort hip movement, causing the rider to rock from side to side. I recommend that shorter people rely on gearing to improve hill-climbing power.

The Freewheel and Cogs

A freewheel contains the pawls that click around and allow you to coast without pedaling. However, the term freewheel usually includes the cluster of five to eight cogs mounted on the freewheel body (or cassette) that makes multi-geared bicycling possible.

Freewheels come in two distinct types:

• The conventional freewheel body on which cogs are screw-threaded one by one to form a cluster. These cogs are spaced a standard 3.5 mm apart. The freewheel cluster is then screwed onto a thread on the rear wheel hub. To remove it, you require a special key or freewheel remover.

• The freehub, a more recent concept in which the actual free- wheel is housed inside a plastic cassette attached to the wheel hub. The cassette contains splines, or projections, similar to those on the spindle of a cassette tape player. Like a cassette tape, each cog fits over the splines on the freewheel cassette. From five to seven cogs can be placed, one by one, onto the freewheel cassette. The eighth, or final, cog is threaded, and is screwed onto the tip of the cassette to lock the other cogs in place.

On a freehub the cogs are spaced only 2.7 mm apart and a special narrow chain must be used. These chains, incidentally, are narrow only on the outside. On the inside, they are standard-sized and will thus fit conventional cogs and chainrings.

While European freewheels are still available, most freewheel production today is Japanese. Among Japan’s newest innovations is the Hyperglide concept, in which each cog has 4 sculpted steps that help the chain move over the freewheel. As a result, the Hyperglide system is currently the fastest and smoothest shifting system made. Furthermore, you can shift down without having to ease up on pedal pressure as you must do with all conventional shifting systems.

The Superglide concept is an even more recent Japanese invention. By using chainrings with uneven tooth profiles, Superglide permits the chain to glide smoothly from one chainring to another even while climbing a hill under full load. Both Hyperglide and Superglide are currently available on mountain bikes.

More Speeds Don’t Mean Lower Gears

Having 24 speeds doesn’t necessary mean that you will have climbing gears that are lower than those available on an 18-speed. Whether you have 6, 7, or 8 cogs, most racing bikes come with a freewheel range of 13T-24T, the standard sports bike has 13T-26T, while most touring and mountain bikes come equipped with 13T-28T or 14T-30T. Larger cogs must usually be custom-ordered. The more teeth on the largest cog, the lower the gears you will have.

Far from giving you lower climbing gears, the 7- or 8-cog free- wheels simply provide more intermediate gears. Moreover, in some types, the largest cogs I could find had only 28T or 30T while the smallest had to be 12T or 13T because only these sizes had the locking thread.

I think the freehub concept is great provided that you can get cogs large enough to match the needs of mature riders. The large 32T cog I recommend for all mature bikers is available on at least one freehub system (the Deore XT) and by now may be available on others. But with some freehub systems you may be stuck with a virtually useless 12T or 13T cog at the high end of your gear cluster because only these small cogs may contain the locking thread.

To sum up: provided you can obtain the cog sizes recommended later, I’d go with a freehub system every time. The freehub systems are also compatible with both narrow-chain and indexed shifting systems. In fact, all are standard on most modern oriental bikes.

Make Your Own Gear Development Chart

If you’ve followed me so far, you already know more than many bicyclists who’ve been riding for years. In fact, you’re already so far along that you can quickly learn to make a gear development chart for any bicycle—even a 24-speed. To many bicyclists, these are also known as grid charts.

All you need to know is this.

Almost all multi-geared bicycles have either two chainrings (a double) or three chainrings (a triple). Meanwhile, freewheels may have from five to eight cogs. Multiply 3 chainrings by 8 cogs and you have 24 speeds, or 2 chainrings by 7 cogs for 14 speeds.

The number of teeth on a chainring is usually stamped on its side. If not, you can count the number of teeth on each chainring. And you can easily count the number of teeth on each cog by flipping the quick-release and removing the rear wheel.

Let’s say you have a mountain bike with a triple crankset that has 26T-38T-48T chainrings and that has 6 cogs with 14T-16T-20T-22T—27T—32T. Using the 26” wheel gear table given earlier in this section, you can easily make a development chart corresponding to Grid Chart 3.1.

Grid Chart 3.1: Developments Compatible with Crossover Shifting for a Bicycle with Triple Crankset

Many bikers carry a similar grid chart attached to their handlebars or handlebar bags. By glancing down at their drive train, they can immediately identify which development they are in and they can decide to which development they may wish to shift next.

Note that no developments are shown for the 48T x 32T and the 26T x 14T combinations. That’s because, with a triple crankset, the chain angle in these speeds is so oblique that pedaling isn’t practical. Thus our 18-speed bike really has only 16 working gear positions, and a 24-speed may have as few as 20 speeds that actually function. Even with a double crankset, you may have to sacrifice one speed when using the smaller chainring.

Avoid Gearing with Duplicate Positions

Something to watch for is the number of duplicate, or near- duplicate, gear positions. For example, our Grid Chart 3.1 has two positions with identical developments of 31” and two others with duplicate 62” developments. Then there are two near-duplicates of 45” and 46”. The difference between riding in a 45” or 46” development is so slight that it isn’t worth shifting for.

At the lower end of the gear range, it’s also hardly worth shifting for gears as closely spaced as 45” and 47”, nor at the higher end for developments as close as 75” and 78”. Such gears are called near- duplicates.

Thus on Grid Chart 3.1 we have two sets of duplicates and one set of near-duplicates. This eliminates three gear positions. While it isn’t always possible to eliminate duplicates and near-duplicates entirely, the fewer you have in your gearing, the better.

Duplicates and near-duplicates often can be eliminated. You won’t find a single one on Grid Chart 3.2 for a 15-speed touring bike:

Grid Chart 3.2: Developments Compatible with Alpine Shifting for a 15-Speed Road Bicycle

Double Shifting

Two distinctly different gear shifting patterns can be used to shift through the gear sequence of any multi-geared bicycle.

• Alpine shifting means shifting up or down one gear step at a time. In Grid Chart 3.1, for example, to shift step by step from the lowest to the highest gear means shifting from the 21” development to 25”, 31”, 34”, 37”, 42”, 45”, 49”, 57”, 62”, 71”, 78”, and 89”— a total of 13 gear positions.

To do this requires at least six double shifts. That is, you must shift to a different chainring, and then shift up or down one or two cogs. To go from 34” to 37”, for example, you must shift up to a larger chainring by moving the left lever, then you must move from the 20T cog to the 27T cog by moving the right lever.

Double shifting means you must shift both front and rear derailleurs to move up or down to the next gear position in the sequence. A shifting pattern like this, involving frequent double shifting, is known as alpine shifting.

Racers don’t have time for such intricate maneuvering. They use a different shifting sequence known as crossover shifting.

• Crossover shifting involves making only a single double shift, or crossover, between each two chainrings. Crossover shifting accomplishes this by sacrificing one or more of the least useful gears.

Using Grid Chart 3.1 again, the crossover shifting pattern would go from 21” to 25”, 31”, 34-D-37”, 45”, 49”, 62”, 71-D-78”, and 89” (D signifies a double shift). Out of a total of 13 possible gear positions, only 10 are commonly used. But the result is an easily remembered shifting sequence for which grid charts are seldom needed.

Alpine versus Crossover Shifting

Although virtually any multiple-gearing system can be shifted using either the alpine or the crossover pattern, it is possible to design gearing that is much more compatible with one of these shifting patterns than with the other.

For example, the gearing in Grid Chart 3.1 is more compatible with crossover shifting while the gearing in Grid Chart 3.2 is better suited to alpine shifting. While it does take 4 double shifts to move through the entire Grid Chart 3.2 sequence, only the shift from 33” to 38” requires a complicated two-cog shift with the right lever. The three remaining double shifts are relatively simple.

These shifting patterns are as applicable to double chainring systems as they are to those with triple chainrings.

Moreover, freewheel clusters are often designed to facilitate one shifting pattern rather than another. The gearing on virtually all racing bikes, and on most sports bikes, is compatible with crossover shifting. Crossover freewheels have wider steps between the larger cogs and closer steps between the smaller cogs. This inevitably creates several duplicate or near-duplicate positions. Yet by sacrificing near-duplicates on the larger and smaller chainrings, crossover gearing permits you to stay in the middle chainring most of the time, using a double shift only when it becomes necessary to switch to the larger or smaller chainrings.

This causes all the gear positions to be bunched up at the high gear end — a situation that most racers seem to prefer.

Alpine Gearing Is Best for Touring

In alpine freewheels gears are more equidistantly spaced and near-duplicate positions are fewer. Because it allows a greater choice of intermediate gears, alpine gearing is preferred by most touring, and by many off-road, bicyclists. To shift through the entire sequence requires several double shifts. But these riders prefer double shifts to riding uphill in high gears. Besides, on a mountain bike with thumb shifters, double shifts are quick and easy to make.

Moreover, since you can shift through any gearing system in either an alpine or a crossover pattern, you don’t have to go through every intervening gear when you shift. Using Grid Chart 3.1, a rider approaching a steep hill will typically shift direct from the 78” position to the 34” one by dropping down two chainrings and by shifting down one cog.

When considering any bike, you should make a gear chart for that bike and consider to which shifting pattern the gearing is most compatible. Then ask yourself if that is the shifting pattern you’ll actually want to use. If not, you can usually change over by judiciously switching some of the cogs.

Design Your Own Gearing

Most experienced bicyclists design their own gearing systems. First they decide on the number of speeds and on the range of gear developments they will want. Then, using the appropriate gear table, they juggle chainring and cog sizes to approach as closely as possible to the developments they prefer. Usually this requires some minor tradeoffs. But if you’ve followed this guide so far, you should have no difficulty designing your own gearing system.

Let’s say, for example, that you have a touring bike with 27” wheels and that you’d like an 18-speed system compatible with alpine shifting. The bike is already fitted with a triple crankset having 26T-44T-50T chainrings. The developments you want range from 22” to 25”, 30”, 35”, 40”, 45”, 50”, 55”, 60”, 65”, 70”, 75”, 80”, 85”, and 95”.

First, prepare a grid chart thus:

Using the 27” wheel gear table, it swiftly becomes apparent that to achieve a high gear of 95” and a low gear of 22”, the outside cogs must be 14T and 32T, respectively. After that, it doesn’t take much juggling to figure out that the remaining cogs must be 17T, 20T, 24T, and 28T. Despite at least two near-duplicates, the completed Grid Chart 3.3 comes very close to supplying all the developments you desire. Because you chose equidistantly spaced gears, your gearing system is most compatible with alpine shifting.

Grid Chart 3.3: Developments Compatible with Alpine Shifting for an 18-Speed Bicycle

Most desired gearing changes can be achieved inexpensively by simply changing cogs. If you fit large cogs where there were small cogs before, you may have to install a larger capacity derailleur also. Switching small chainrings is equally inexpensive. Other than that, it’s invariably cheaper to make changes to your freewheel than to your crankset.

Which Gearing Is Best?

That depends on the individual rider, of course. But if I were to generalize, I’d suggest that the average beginning adult would do well to consider a triple crankset matched to a freewheel cluster to provide a range of gears with developments from 21” or 22” to around 90”.

Regardless whether you buy a racing or a sports bike, or a touring or a mountain bike, you can safely buy one that has a triple crank set. In response to the growing demand from mature riders, some makers are beginning to produce racing bikes with triple cranksets while triples are fairly common on sports bikes and triple cranksets are taken for granted on touring and mountain bikes. Having a triple crankset makes it much simpler to install the low climbing gears that most non-athletic adults need to pedal uphill.

On a sports bike, I’d aim for a 26T—44T—50T triple crankset and on a touring bike for a 26T—42T-46T chainring combination. For a mountain bike, chainrings with 24T-36T-46T would seem most ideal with 26T—38T-48T as second choice. Most stock mountain bikes have 26T—36T-46T or 28T—38T-48T chainring sets. In most cases, I recommend replacing the factory-installed small chainring with another that has fewer teeth.

For touring and mountain bikes, I’d also prefer an alpine shifting pattern.

Almost without exception then, I’d recommend a freewheel cluster with from 14T-32T. Most stock mountain bikes have 13T-28T cogs while road bike freewheels have an even narrower range. Some bike shops may have to custom-assemble a conventional freewheel with 14T-32T. However, I’ve generally found that conventional 14T-32T clusters are readily available, often quite inexpensively.

On this basis the gearing in charts 3.1, 3.2, and 3.3 should be eminently suitable for most beginning adult riders. To add to my recommendations, you might consider the crossover-compatible gearing system given in Grid Chart 3.4 for a mountain bike.

Grid Chart 3.4: Developments Compatible with Crossover Shifting for an 18-Speed Bicycle

A Double Chainring System

You may have to hunt around but double cranksets can be found with chainrings in the 28T-42T range. In fact, one of the most experienced bicycle tourists I know uses the system illustrated by Grid Chart 3.5.

Using a crossover shifting pattern, he simply moves up from 24” through 27”, 31”, 38”, 45”, 54—D-57”, and 67” to 81” — employing a total of 9 commonly used gears. Should he be going too fast for his 81” top gear to keep pace, he coasts until his speed drops back down. His rationale is that if he’s going too fast for his 81” development to keep pace, he’ll be needing his brakes rather than a higher gear.

A double chainring system like this could supply virtually all the gears needed by the average mature adult, whether for touring, off- road riding, or even for day rides on a sports bike.

Grid Chart 3.5: Developments Compatible with Crossover Shifting for a 12-Speed Bicycle

The Key to Success in Adult Bicycling

Never lose sight of this fact: Of all the variables that can enhance your bicycling performance, having the right gear development for each of your speeds is the most vitally important factor.

A good general guide is that most stock bikes have small chainrings that are too large and large cogs that are too small to match the capabilities of most mature riders.

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