When you shop for a road bike, the first thing you'll notice is that they don't come with any pedals. So what's up with that? Road bikes use what's called "clipless pedals", and each cyclist will choose the specific brand and model that they like best. These are installed once you purchase your bike.
The word "clipless" is a bit of a misnomer, because your new cycling shoes will actually "clip" into the pedal. The reason they're called clipless is because pedal designs from decades ago, had what was called a "toe clip" attached to the pedal. You may remember having these as a child. You could wear any shoe and you would slide your foot forward into the "clip" to hold your foot in place. While these were certainly an improvement in cycling performance, their design left a lot to be desired. Sometimes it was awkward sliding your foot in, and other times it could be difficult sliding it out.
A company named "Look" borrowed a design premise from their ski bindings and adapted it to cycling shoes. A plastic piece was mounted to the bottom of your shoe (called a cleat) and it snapped into the pedal. This innovation is considered one of the greatest advances ever made in cycling. Having a "clipless" pedal allows a cyclist to transfer all of their effort directly to the pedals, on both the upward and downward pedal stroke. Plus, no longer would your foot slide around on the pedal wasting energy.
If you plan on road biking, than you're going to want to get clipless pedals. While you can certainly use standard pedals, they're so inefficient, that you're not fully benefiting from having a road bike. There's several manufacturers of clipless pedals, and each of them has numerous models to choose from. So which one do you get?
For a first pedal it's best to go with a wide platform pedal made by Look or Shimano. These are both very similar in design and performance. You'll want to get a model that has an adjusting screw for the release tension setting. This setting determines how much pressure is required to release your foot from the binding, by twisting your heel outward. You'll be able to fine-tune the pedals based upon your weight and how aggressively you ride.
If you're slow and deliberate, than go with a low setting. If you're strong and aggressive, than you'll want to crank it up a bit. This setting is something that you and your bike shop can determine. Remember that entry-level pedals will generally have lower (easier) release settings, and expert-level pedals will have higher (harder) release settings. So don't go for the most expensive model to start with. The tension setting may be too high for your riding ability.
Besides Look and Shimano there are a couple of other pedal designs worth noting. Speedplay uses a totally different design philosophy than other manufacturers. They have the release mechanism mounted on the bottom of the shoe (not the pedal), and mounted on the bike is the other half of the pedal assembly, which resembles a lolly-pop. Speedplay's are often referred to as "lolly-pop pedals". There are advantages and disadvantages to this design. Advantage is that there is no top or bottom to the pedal, so you can clip in without worrying about which side is up. The disadvantage is that the spring mechanism is on your shoe, and if you walk in mud it will clog with dirt. This isn't a problem for most cyclists, yet it's something you need to be aware of. Also, Speedplay pedals have a different "feel" to them because of their unique design, so you want to try them out first, to be sure they're right for you.
You may also see pedals from Crank Brothers that look like the egg beaters you would find on a mixing bowl. Although these work well for mountain bikes, they're not the best choice for a road bike. The shoe platform is simply too small for road riding. Another notable company is Time, whose pedals use a different type of spring mechanism than Look and Shimano. Time pedals aren't carried in as many bike shops as the other models, yet they have a loyal following of cyclists; just as the other brands do.
It's important to try out more than one brand of pedal to see which one works best for you. This isn't as easy as it sounds, because bike shops won't let you buy pedals, try them for a week, then return them. You have to find a shop with demo pedals or let you ride a floor model bike that has pedals already mounted on it. At the very least, have them set up your bike on a trainer, so you can practice clipping in and out of different models.
Decent entry-level pedals will cost around $100.00 or so. Mid-range go for about $200.00 and racing pedals (titanium) can cost upwards of $300.00-$500.00. So plan on spending about $100.00 for your first set of pedals. And finally, pedals are not an item that you'll want to shop for the cheapest price. Saving $30.00-$50.00 isn't worth it, if you can't clip and unclip with ease. Would you rather fall because you saved a few dollars, or smoothly unclip because you got just the right pedals?
You'll learn very quickly that cycling shoes aren't designed for walking, they're designed for riding. The sole (bottom) of the shoe is rigid, with no flex. This is important in order to transfer all of your energy from pedaling, directly to the gear train. If the shoes flexed, you would be wasting motion and energy on each turn of the crank. More expensive shoes will have a carbon sole, and less expensive models will use plastic. Obviously carbon is much better; it's strong and lightweight.
The bottom of cycling shoes will have either 2 or 3 screw holes for mounting cleats. Most road pedals are 3 screw mounts, so you really need to pick out your pedals before your shoes. In the event you choose a pedal with 2 screws, than you'll need to pick out a matching shoe.
The upper-half of the shoe can be made from a variety of materials, with some being more "breathable" than others. The type of upper material will determine the overall fit and "feel" of the shoes. Some are flexible and others are stiff. You need to try on a variety of shoes in order to determine what feels best to you. Be sure to check for any "hot spots" where there's excessive pressure on your foot.
The most popular closure or buckling systems on cycling shoes, is velcro. Most shoes will have either 2 or 3 velcro straps. Better shoes with usually have two velcro straps and a ratchet buckle at the top. The ratchet gives you a more snug fit and a little better performance. As tight as velcro is, it still has a bit of "give" to it, and you may notice this when pedaling hard, with velcro closure shoes. Having a buckle eliminates this problem.
Cycling shoes are all sized in European shoe measurements. This is because the preeminent manufacturers started in Europe and every other cycling shoe company has followed the same sizing scheme. For example, a US size 9 would convert to a European size 39 (approximately). There are slight variations in the conversion table, so you'll simply need to try on a few different sizes to see what fits best. It's important to know that more expensive cycling shoes will come in 1/2 sizes, such as 39, 39 1/2, 40, for a more precise fit. Less expensive shoes will not. So you may have to consider a slightly more expensive shoe in order to get the best fit.
Entry-level shoes will cost less than $100.00. Better quality shoes with a ratchet buckle and carbon sole will be $150.00-$200.00. And top-level shoes will sell for $300.00-$500.00. Each bike shop will carry several different brands of shoes, and you may need to go to more than one shop to find the shoes you like best. Experienced cyclists will eventually purchase a pair of expensive shoes, such as Sidi, that are in the upper price range. That's because they have an incredibly good fit, finish and warranty. Even though you may not plan on spending that much, you should still try on an expensive pair, so that you can compare the fit and feel to less expensive brands. You certainly won't overpay for shoes. You'll just be paying for the best fit possible.
It's worth noting that cycling cleats (the part that mounts to the bottom of your shoe) will wear out from walking around when you get off of your bike. You can carry a pair of rubberized covers to protect the cleats, or simply purchase a new pair when they wear out - perhaps each season. If you don't replace them ($20.00), a worn cleat can become "sticky" and won't release from the binding as expected. You don't want that to happen. So consider new cleats one of your annual cycling maintenance chores.
While there are many pedal and shoe combinations available, you should be able to find just the right products for your style of riding, by following some of the basic principals outlined above. Just be sure to try out the exact shoe and pedal combination you plan on purchasing, before leaving the bike shop.