Bike Repair & Maintenance For Dummies®

by Dennis Bailey

  With longer crank arms it’s important to make sure the bottom bracket has enough clearance. If you buy a bike with a crank arm that’s too long, the crank arm may hit the ground when you’re cornering.

  Your height will impact the length of the crank arm you chose. In most cases, taller bikers should have longer crank arms, and shorter bikers should have shorter crank arms.

  A number of different crank arm lengths are available. It’s common to see lengths of 165mm to 180mm in 2.5mm increments, with the most common lengths being 170mm and 172.5mm. If you’re in the NBA, you’ll be glad to know that a few manufacturers will sell you a crank of 185mm or more. Work with your local bike store to find the crank the best suits you.

  Going for Gearing

  Choosing the appropriate gearing may not be fitting a bike in the traditional sense, but it is an important factor in how well a bike fits the way you ride. By selecting a bike with the gearing that meets your fitness levels, how you pedal, and the terrain on which you ride, you can make a significant and positive impact on your riding experience.

  Most newer bikes have seven to ten cogs in the rear and two to three chainrings in the front. Multiply these two numbers together and you have the total number of gears for your bike. If you’re in shape and you don’t do a lot of climbing, you’re probably fine with seven to eight cogs and two chainrings. Some riders like to have a third chainring in case a climb is necessary or fatigue sets in at the end of a long ride (though that third chainring does add extra weight and three chainrings won’t shift as effortlessly as two); third chainrings are also useful for mountain biking and touring.

  If you’re planning on doing a lot of mountain biking or touring, talk to your local bike shop to make sure you have the right gearing. They can give you advice not just about the total number of gears but about the size of the individual cogs and chainrings, important factors in gearing. (For a more detailed discussion of gearing, turn to Chapter 2.)

  Resisting the Temptation to Tilt Your Saddle

  Some people are tempted to tilt the saddle downward in an attempt to find a more comfortable position and relieve pressure on the groin. Resist the temptation! The problem with this position is that it causes you to slide forward against the handlebars, which puts additional weight and stress on your arms, wrists, hands, and shoulders. In the other extreme, a saddle tilted upward can cause discomfort, especially for men — and we don’t need to explain why!

  In general, we recommend that you try to keep your seat flat and parallel to the ground. To check the straightness of your seat, place a level on top of the seat, and make adjustments as necessary.

  Setting the Saddle Height

  Saddle height is an important factor in fitting your bike. A saddle set too high reduces the amount of power available for pedaling and causes you to stretch for the pedals on the down stroke and rock back and forth on the saddle, which can cause soreness. A saddle set too low doesn’t allow you to use your leg muscles efficiently, puts extra strain on the knees, and can lead to injury.

  We notice many riders whose saddles are not at the proper height, sometimes significantly so. Odds are, a rider whose saddle isn’t set to the proper height made some adjustments over time that affected the saddle height but didn’t know exactly where to set it. In Chapter 18, we give you step-by-step instructions for choosing the proper saddle height for your bike.

  After you’ve set the correct height for your saddle, mark the seat post with tape or a small score in the metal so you can easily return it to that position if the post comes loose or you have to remove it.

  Looking at the Saddle Fore and Aft

  The fore and aft are how far forward and backward the saddle is on your bike. If the saddle is too far forward, you lose leverage when you pedal; if it’s too far back, you could be putting strain on your back. As with most parts of the bike, the fit depends on how you’re going to be using your bike. If you’re racing, you’ll want to have the saddle in a more forward position along with the handlebars, which will put you in a more bent-over, aerodynamic position, and allow you to deliver more power to the pedals. If you’re not racing, though, the best position will have the saddle nose behind the bottom bracket.

  To find the proper fore and aft position, sit on your bike with the pedals parallel to the ground while someone supports you. Hang a string with a weight tied to the end of it from your kneecap down past the pedal. The line from your kneecap should pass through the center of the pedal where the axle threads into the crank arm (see Figure 19-1). If the string is in front of the pedal, move the saddle forward. If the string is in back of the pedal, move the saddle backward.

  Figure 19-1: Use a string to set your saddles fore and aft position.

  After you make the adjustment, give your bike a test ride to make sure you feel comfortable. Remember that after you first change the position of the saddle, you may feel a little strange. Give it some time before you make a final decision on where it should be.

  Choosing the Right Saddle Type

  Unless you’re a racer competing in sprints, you’re going to be spending the majority of your time biking with your bum on a saddle. The saddle is one of the three points of contact your body has with the bike (the pedals and handlebars are the other two), and the saddle is where a lot of your weight is.

  Some saddles are designed to support the specific anatomy of men, while others are designed for women, so make sure you choose the right one. Saddles for men are normally longer and narrower and sometimes have cutout sections or extra padding to help prevent numbness. For women, saddles are shorter and wider toward the back to better accommodate a woman’s wider pelvis. (Children use smaller sized saddles than adults do.) Figure 19-2 shows the differences between saddles for men and women.

  Figure 19-2: Saddles for men (right) and women (left).

  Saddles come in a variety of different materials. Leather saddles conform to the shape of your butt, although they require special care, especially in wet weather. Other saddles are made with gel or foam padding with many different coverings that are more resistant to the elements.

  You may think that a bigger, softer saddle would equal a more comfortable ride. Unfortunately, bigger and softer does not translate into comfort. Weight from your body should come into contact with the seat through two bones at the lower part of your pelvis. If you have a properly fitted seat, when you get off your bike, you should see two indentations centered on each side of your seat. If the seat is too soft, your entire butt is in contact with the seat causing pressure on tissue and nerves that are not designed for this. Although a firmer seat may cause your pelvic bones to be sore after the first ride or two, in the long run, you’ll find that it provides the most comfortable ride. As crazy as it sounds, the more you ride, the smaller the seat you’ll want.

  For comfort, wear biking shorts, which are designed without seams in the crotch area — seams can chafe and rub the soft tissue in the crotch. Biking shorts also include extra padding or chamois, which provides extra comfort, wicks away moisture, and keeps bacteria at bay. Just make sure you wash your biking shorts after each ride. Also, don’t forget to remove your underwear when you wear them — the goal is to have no seams and less material to bunch up and cause chafing.

  If you have problems with rubbing and chafing in the groin area, consider applying a skin lubricant such as Vaseline. Some lubricants, such as Chamois Butt’r, are designed specifically for bikers.

  Sizing Up the Frame

  Frame size is the most important consideration when fitting a bike. Unlike most other factors, the frame is one thing you can’t modify. If you end up with a bike that has a frame too small or too large, you won’t be able to adjust the saddle and handlebars enough to compensate for the improper dimensions. Plus, an incorrectly sized frame can be dangerous, making starting, stopping, and handling more difficult. />
  When you’re shopping for a new bike or frame, let the staff at your local bike shop assist you. They have experience matching customers to bikes, and they understand the different factors that come into play when choosing a frame.

  The bike-shop staff will want your inseam size. This is the length from the floor to the top of your crotch. They’ll take this number and subtract 10 to 12 inches from it, based on how tall you are, which will give them an estimation of the frame size you need. Remember: This is just an estimation — every bicycle will fit a little differently, depending on the manufacturer, model, type of bicycle, your riding style, and so on.

  Frames are generally measured from the center of the bottom bracket to the top of the seat tube (see Figure 19-3), although manufacturers have different variations of this measurement. After the bike-shop staff has a general idea of the frame size, they’ll have you try out various bikes with this size. To confirm the size, they’ll have you straddle the bike with both feet on the ground and the frame between your legs. In this position, there should be at least an inch or two of space between the top tube and your crotch, more if it’s a mountain bike.

  Figure 19-3: How frame size is measured.

  Focusing on Frame Dimensions

  If your local bike shop determines that you need a certain size frame, they’ll still need to have you sit on the bike to confirm that the frame’s dimensions suit your body type. Two 20-inch frames can vary significantly based on the dimensions in which they were manufactured. A shorter version of a 20-inch frame will provide greater performance and handling; in this case, the seat tube will be more upright, requiring you to sit in a more aerodynamic, bent-over position. Another 20-inch frame may have a longer base to provide stability and comfort and a more sloped seat-tube angle for a more upright ride, both of which provide benefits when touring.

  As a general rule, when you’re seated on a bike with your hands on the handlebars and feet on the pedals, the handlebars should block your view of the front hub. Another rule of thumb is that in your natural reach, your arms should make a 90-degree angle to your torso. On road drop handlebars, of the three holding positions, the middle lean (hands over brake levers) should obscure the hub with the handlebars.

  In general, you shouldn’t be stretched out like Lance Armstrong or sitting upright like you’re getting a haircut. There should be a slight bend in your elbows and they shouldn’t be locked out or pressed into your ribs.

  If the top tube is slightly too long or short, this can be compensated for by adjusting the stem length. The stem can be raised or lowered; with adjustable stems, the angle can be adjusted as well.

  Positioning Your Handlebars

  The handlebars are one of the three points where your body comes into contact with your bike, so you need to take the time to set them in the position that’s most comfortable for you.

  Before adjusting your handlebars, make sure you’ve found the appropriate height and angle for your saddle. If you don’t have the saddle in the proper position, you won’t be able to set the handlebars correctly.

  For most everyday riders, the handlebars should be even with or slightly higher than the seat. When you sit on the bike and grab the uppermost part of the handlebars and straighten your arms, your back should be at a 45-degree position. If you’re looking for a more aerodynamic position, the bar should be an inch or two lower than the saddle. In this position, the angle of your back will be less than 45 degrees.

  The height of the handlebars is sometimes limited by the type of stem you have. On some threadless stems, spacers can be used to adjust the height. If this doesn’t provide enough of a change, you can replace the stem with an adjustable one that provides more range to move the handlebars.

  For road bikes with dropdown handlebars, the other adjustment to consider is the angle. The traditional approach was to have the bottom of the handlebars line up parallel to the top tube. But if you don’t want to be bent over in a position better left to yoga classes, a more appropriate angle is for the bottom of the handlebars to be closer to parallel with the seat stays, as shown in Figure 19-4.

  Figure 19-4: The proper handlebar angle.

  Getting a Handle on Handlebar Style

  Like many other parts of the bike, there are a plethora of different styles of handlebars on the market. You can find handlebars for road racing, mountain biking, touring, and everyday riding. Of these different types, two shapes are predominant — the drop-down road-bike style and the flat mountain-bike style.

  Regardless of the style of handlebars you choose, choose a width that comes close to matching the width of your shoulders. This width will keep your arms parallel while you ride and your chest open for efficient and relaxed breathing.

  Your hands should be in a relaxed position when you grab the brakes. Your wrists should not be angled down over the handlebars when squeezing the brakes. An awkward angle for your wrists will cause pressure on the nerves and lead to an uncomfortable numbing sensation in the hands and wrists.

  Frequently change the position of your hands when you ride. One way to increase the number of positions for riding is to add bar-ends to your flat, mountain-bike-style handlebars. Not only do bar-ends give you an alternative position, but they can be beneficial for climbing. Just remember that your hands will be farther away from the brakes, which could be a problem if you have to stop suddenly.

  Chapter 20

  Ten Ways to Improve the Performance and Comfort of Your Bike

  In This Chapter

  Taking your bike to the next level

  Making all your friends jealous with your upgrades

  One of the joys of owning and working on a bike is the chance to upgrade its parts. Just like car tuning, tuning your bike can help you improve both comfort and performance while you ride. Odds are, doing a complete overhaul of your bike is probably not in your price range, especially considering that some higher-end components can be pretty pricey. But if you’re going to be repairing and maintaining your bike, you may want to add on a high-performance part once in a while. In this chapter, we present ten options to consider if you’re thinking about upgrading.

  Upgrading Your Wheels and Tires

  One way to significantly impact your bike’s performance is to upgrade the wheels and tires. If you can drop the weight of the wheels and tires even slightly, you’ll notice a definite difference when you bike.

  Many options are available for upgrading your bike’s wheels. Major wheel manufactures offer products with a variety of rim styles made of different materials. Wheels are also available with an assortment of spoke designs. Because of the improved quality of spokes, wheels are being built with fewer spokes but with comparable strength and durability.

  If you upgrade your tires, you’ll realize another performance gain: Higher-quality tires provide reduced weight and less rolling resistance, which makes a dramatic difference in performance. Better-quality tires are designed with more threads inside the rubber, which holds the tire together, allowing for greater air pressure, less contact surface, and a fast ride.

  The tread pattern on the tires also has an impact on ride comfort. The less tread on your tires, the less rolling resistance and the better performance you’ll experience.

  Most wheels allow you to change the width of your tires. Tire width impacts performance — narrower tires give you a faster ride because of their decreased rolling resistance, and wider tires are more comfortable because they absorb more road shock (although wider tires have more tread on the road and more rolling resistance). To determine the width of your tire, look at the dimension written on the sidewall of your tires; specifically, look for the second number. A marking of 700x25 means the tire has a circumference of 700cm and a width of 25cm. If you plan on changing the width of your tires, work with your local bike shop to make sure you find tires that work with t
he dimensions of your frame.

  The other important consideration when choosing tires is durability. If you’re touring and riding a significant number of miles with fully-packed pannier bags, you’ll want a very durable tire that can handle the weight. A more durable tire will also lead to fewer flats along the way. Many of the tires specially designed for durability have a Kevlar belt or other material designed for protection.

  If you want protection from flats but don’t have the money to upgrade your tires, you can fill your bike’s tubes with a puncture sealant. The liquid inside the tube will automatically fill any punctures that may occur. In addition to puncture sealant, you may want to opt for thorn-resistant tubes (which are thicker than normal tubes) and tire liner (a protective stripe of Kevlar that you place between the tire and tube). The downside to this flat protection, however, is significant added rotational weight — but if you absolutely hate flat tires, you won’t mind trading some performance for convenience.

  Ramping Up Your Rear Derailleur

  The rear derailleur is the biggest factor in shifting performance. Top-end derailleurs have stronger springs and tighter bushings and pivot points that allow for easier and faster shifting. These derailleurs are designed with jockey wheels with higher-end bearings, which cause less resistance and smoother chain movement, which, in turn, improves chain life and derailleur life.

  Pair a top-of-the-line rear derailleur with an upgraded shifter, and you’ll multiply the impact of that derailleur and find that you can change gears with barely a flick of the finger.