Putting the Pedal to the Metal: The Drivetrain

In This Chapter

^ Working on pedals ^ Removing and installing crank arms ^ Dealing with chainrings ^ Handling the bottom bracket

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he drivetrain is sort of like your bike’s transmission. It converts energy from your legs into mechanical force to power you forward. The drive­train starts with pedals attached to the bike’s crank arms, which are mounted to the frame by the bottom bracket. Moving the pedals begins a process that drives your energy through the chain to the back wheel, moving the bicycle forward down the trail. In this chapter, we explain how to remove, install, and overhaul each of the components that make up the drivetrain.

Working on the drivetrain is not overly complicated, but it does require some special tools, including special wrenches, bottom bracket tools, crank-arm extractors, and so on. If you’re committed to a long-term relationship with your bike and want to do your own repair and maintenance, purchasing these tools will be a good investment. Otherwise, when it comes time to overhaul these parts, you can always take your bike to your local bike shop and let the experts there handle the job.

Putting the Pedal to the Metal

The pedals are an important link in the transfer of power from your legs to your bike. However, if you were buying a new bike, you wouldn’t get that impression because manufacturers sometimes install the cheapest, most low-end pedals possible.

Dennis recently bought a new road bike for his wife. To look at it was to admire a work of art. . . except for the ugly, thick, rubber pedals attached to the cranks, which looked as if they were taken from a child’s bike.

Manufacturers use cheap pedals because many bicyclists develop personal preferences for certain types of pedals and, when they buy a new bicycle, they have their old pedals mounted on their new bikes — or buy a new set of pedals.

In this section, we show you what to look for in new pedals and tell you how to keep your pedals working well.

Shopping for new pedals

There are many different pedal styles on the market. The traditional style pedals are flat. Other styles have binding systems that allow you to strap your foot to the pedal with a toe clip and strap or lock your shoe into the pedal with a clipless pedal.

■аУ b Many casual riders think that having their feet attached to the pedal would be uncomfortable or worry that disengaging their feet would be difficult. On ■ (oj■ the contrary, toe clips or clipless pedals are easy to manage, and they offer significant gains in performance.

On most pedals, you can attach a toe clip and strap, which helps prevent your foot from slipping off the pedal and keeps the ball of your foot centered over the pedal, which improves the efficiency of your pedaling. Toe clips include a buckle that allows you to adjust the strap so that it can fit a variety of shoe types and sizes. Because you can wear any type of shoe with them, these are especially nice if you’re a casual rider and like to get off your bike occasionally and sightsee or just walk around.

Another option is to go with clipless pedals, which are similar to ski bindings. They’re designed to grab a cleat built into the bottom of specially designed biking shoes. These pedals hold your foot in place while you pedal, greatly increasing your pedaling efficiency. Snapping your shoe into the pedal is a breeze, and unlocking the cleat and removing your shoe from the pedal is a quick, natural movement with an outward twist of your heel.

There are a number of different clipless systems on the market each with a slightly different method for locking the cleat into the pedal. If you’re buying biking shoes, make sure you check them for their compatibility with your pedals, and vice versa.

If you’re worried about whether you’ll be able to unlock the cleat from the pedal quickly enough in an emergency, don’t be. We can pull our shoes off the pedals faster with clipless pedals than we can with toe clips. Plus, clipless pedals are usually designed with a tension adjustment — usually a small bolt that’s turned clockwise to increase tension and counterclockwise to reduce tension. If you find that the cleat in your shoe is a little difficult to remove, try adjusting the tension. Practice getting in and out of your clipless pedals a few times before you ride so that you don’t come to your first stop and fall over with your shoes locked into your pedals.

If you opt for clipless pedals, you’ll want to adjust them to the pedaling posi­tion that is most natural for you. Many shoes allow you to move the position of the cleat. In addition, some pedal systems provide for some movement or float after the cleat locks into the pedal — this gives your feet some ability to move on the pedal, which reduces tension and stress on the knees and keeps you from staying in one position during your ride.

Talk to the staff in your local bike shop to find the right adjustment for your pedaling system. This will help ensure that you don’t end up locking your shoes into pedals in a position that’s unnatural for your body and puts strain on your legs when you bike.