Cyclopedia of Bike Types

Most bike models can be roughly classified into several categories—mountain bikes, road bikes, city bikes, touring bikes, and cruisers—although manufacturers often mix and match characteristics of several types to create new models.

To narrow your choices, think about what you expect to do with your bike. Will you run errands, commute, work out, compete? How often will you ride? Every day, weekends only, hardly ever? What kind of surface will you ride on? Smooth roads, potholed city streets, off-road trails? How hilly will the terrain be? Do you care how fast you can go?

In general, the more you plan to ride and compete, the more the bike will cost.

The brief descriptions of bike types below might help, but you’ll need to acquire hands-on experience to appreciate the differences by visiting bike shops, trying friends’ bikes, or renting bikes.

Mountain Bikes

Mountain bikes consist of wide (1 3/4 inches and up) high-traction tires; either flat or riser handlebars, depending on riding position; at least 18, and possibly 27 or more, gear ratios extending into the low, low range; and a sturdy frame that allows substantial clearance between pedals and the ground. This combination, along with a number of other details, yields a bike that can be ridden off-road on rugged up-and-down terrain and at the same time allows riders to sit in a comfortable, upright position on smooth roadways.

Road Bikes

Road bikes have tires that are often less than an inch wide and pumped to a very high pressure, drop (“ram’s horn”) handlebars, ultra-lightweight construction, caliper-type handbrakes, narrow seats, and a wide range of gear ratio combinations. Built for high speed and crisp handling, road bikes cover a lot of ground fast on commutes, on recreational day rides, or in competition.

A road bike requires careful tuning and maintenance; expensive versions are extremely high-tech precision machines. For some riders, the bent-over riding position, seat configuration, frame design, and narrow tires make it extremely uncomfortable to ride. In addition, the riding position and quick steering response discourage casual sightseeing, and the narrow tires and lightweight precision construction aren’t suitable for rough terrain. Still, some bolder cyclists love a road bike’s ability to travel vast stretches of open road at high speeds.

City Bikes

Most city bikes are less rugged versions of mountain bikes, with smoother, narrower tires for easier pedaling on road surfaces. Like mountain bikes, city bikes offer an upright riding position and have shock-absorbent construction—making them preferable to commuters and daytrippers. But city bikes can’t be pedaled as efficiently as road bikes.

Touring Bikes

Touring bikes look a lot like road bikes, but are designed for longer trips. Compared to road bikes, the tires are wider (typically 1 1/8 or 1 1/4 inches), the tubes to which handlebars and seat are attached are less upright, the distance between seat and handlebars is shorter, and the distance between front and back wheels is longer.

These differences produce a more comfortable and stable ride; a more upright riding position; and steering that tracks more easily. Touring bikes have different gear ratios than road bikes, with more gears at the low end for uphill rides. Within the touring category, you are likely to find a single “compromise” bike suitable for reasonably high-speed daytrips and commutes, but also serviceable for multiday treks with heavy packs—most touring bikes are equipped to add a wide variety of racks for carrying duffel bags, camping equipment, coolers, etc. If you’re considering a touring bike, also consider city bike options.

Cruisers/Urban Bikes

At the opposite extreme from road bikes are cruisers or urban bikes. The direct descendant of 1930s, ’40s, and ’50s models, cruisers have fat tires, upright handlebars, large seats, and, in most cases, coaster brakes (applied by pushing down on the back pedal). Cruisers are ideal for comfortable, leisurely riding and sightseeing on level terrain. They are simply constructed, easy to maintain, and durable, but provide a poor way to climb hills or go fast.

Hybrid Designs

In order to provide still other speed/ruggedness combinations, “hybrid” or “cross” bikes borrow some features from road bike designs (i.e., drop handlebars, narrower tires) and other features from mountain bikes (i.e., rugged frame, high pedal clearance).

Other Designs

Other bike design variants include traditional three-speed bikes and “BMX” and freestyle/trick bikes popular with kids. Among mountain bikes, designs specialized for activities such as cross-country, downhill, and extreme riding are available, all with different variants on suspension, tire width, and body position. Fixed-gear, or track, bikes similar to road bikes but with only one gear combination are options if you want a simple design. New variants continue to appear as new materials and manufacturing techniques create new possibilities, and as the highly competitive bicycle manufacturing industry searches for new designs to fulfill consumer desires.

Construction and Important Features

In addition to deciding what type of bike you want, you’ll need to sort through the various construction materials and features that often impact performance, comfort, and durability. The best way to get a feel for what’s available is to visit several bike shops, but we’ll touch on a few of the major considerations here.

Frame

The central—and usually most expensive—component of a bike is its frame. Frames should be lightweight, durable, rigid (so you won’t dissipate energy bending the frame, rather than moving the bike), and dampen vibration from road or trail. Frames vary in quality according to what they’re made of and how they’re put together.

The least-expensive bicycles—generally found only in department stores, discount stores, and other outlets that don’t specialize in bikes—are made of low-carbon or carbon steel. Low-carbon steel bikes tend to be very heavy, around 35 to 45 pounds. Their main virtue is price: sometimes under $100.

Chromoly, a lighter, stronger, more high-tech version of carbon steel that was at one time the predominant material in the mid- to high-end bike market, has been replaced by other metals.

One of them is aluminum. Although not nearly as strong as a good steel, aluminum is much lighter than steel. Aluminum tubes can have thicker walls or larger diameters than steel tubes without weighing more. And because small increases in diameter greatly increase a tube’s strength, larger-diameter aluminum tubes can be as strong as smaller-diameter steel tubes. In addition, aluminum frames usually create a stiffer ride than steel frames. Aluminum is now commonly used in lower-middle- and mid-priced bikes.

Titanium is also available in some high-end road bikes and mountain bikes. Like aluminum, titanium frames are lighter than steel but just as strong. And titanium flexes so well while maintaining its shape that it can be incorporated into designs that allow the metal itself to act as a shock absorber. And while titanium frames are also generally more durable than aluminum frames, these benefits come with a very high price tag.

The ultimate frame material is carbon fiber, which is made from strands of light, strong metal fibers bound together with resin. Modern carbon-fiber designs create very tough, very light, very expensive bike frames.

Among the different frame materials, there is no outright winner. Extremely high-quality frames can be made from carbon fiber, titanium, aluminum, and even high-quality steel alloy. The keys to making the best choice are the specific ways materials are treated and assembled, your riding preferences, and price.

Rims and Tires

After the frame, wheels are a bike’s most important components. Like the frame, rims can be made of many types of metals, with similar tradeoffs between weight, strength, performance, and price.

Tires should let you expend as little energy as possible to propel the bicycle. The less tire surface meeting the road, the less friction. Hard tires with slick treads require less energy than soft tires with “nubby” treads. Accordingly, you’ll travel fastest with the least effort on narrow, hard, low-tread tires. Unfortunately, these kinds of tires are the least comfortable, least durable, and least protective of rims, and provide the least traction on rough terrain.

The most expensive tires are manufactured to be very light and have high pressure ratings. Lighter tires inflated to a high air pressure let you accelerate relatively easily because the tire has low rotating mass and loses relatively little energy in flexing the sidewalls of the tire. The downside of lightweight high-pressure tires is that they are more easily punctured and provide less traction and rougher rides over bumpy terrain than heavier tires.

Gears

The advantage of a bicycle with 18 or more speeds over one- or three-speed bikes is that riders can adjust them to the terrain. To limit fatigue and muscle and joint stress, cyclists try to maintain a constant pedaling rate. The higher number of gears makes this easier to accomplish.

Gear ratios are described in terms of “gear inches.” Lower numbers mean easier pedaling. Most moderately priced touring bicycles let the rider select ratios from 40 to 100 gear inches. Bicycles designed for well-conditioned racers generally have gearing between 55 and 110 gear inches. Gearing on all-terrain bikes often ranges from about 25 gear inches to more than 100 gear inches.

The actual number of gear positions available depends on whether the bike has two or three chainrings (gear sprockets by the pedals) and whether it has six, seven, eight, or more chain cogs on the freewheel (at the rear wheel hub). Two chainring positions and seven freewheel positions produce a 14-speed (2x7) bike; three chainring positions and seven freewheel positions produce a 21-speed (3x7) bike.

Other Features

There are many other features to look for on bikes: seats gel-padded for comfort; a quick release lever (good for quick adjustment with changing terrain on off-road bikes); pedals with toe-clips or clipless attachment mechanisms to increase pedaling efficiency; handlebar width and whether they are drop type or upright; etc. You can learn more about what to look for by visiting cycling websites, talking with other cyclists, consulting bike store personnel, and looking at bikes and accessories in stores.