Below is an excerpt from the book "The No-Drop Zone: Everything You Need to Know About the Peloton, Your Gear, and Riding Strong" by Patrick Brady. The 250-page book outlines all aspects of road cycling for beginners, from riding skills to bike gear to the cycling lifestyle. Learn more about the book here.
Easily the biggest improvement you can make to your bicycle comes from purchasing a set of high-quality wheels. The benefits of a set of racing wheels can be reduced weight, greater aerodynamics, or, if you are willing to spend enough, both.
It used to be that a high-quality wheel set was built by a veteran mechanic at your local shop. Today, that isn't as common; most wheels come prebuilt from the factory. Find the shop in your area with an experienced wheel builder, because any time you need your wheels serviced, his experience will be helpful.
If you live in an area with hills or mountains, the local climbers will all have lightweight wheels. For less than $1,000 you can purchase a lightweight set of wheels that will be easier to accelerate due to their reduced rotating mass, which will help you on climbs.
Aluminum rims are still king in the sub-$1,000 market; they are easier to service and don't require new brake shoes. Low weight for a set of aftermarket wheels is 1,500 grams for the wheel set (no skewers, cassette, tires, or tubes).
While reduced weight is immediately apparent upon picking up a bike, most engineers are saying that aerodynamics trumps weight. A deep-section rim (generally defined as any rim with a profile of 30 mm or greater) does increase weight, but it will more than offset that increase in weight by increasing the wheels' aerodynamic efficiency; though heavier, the wheel is faster.
A pair of deep-section aluminum rim wheels is the most cost-effective method to make your bike faster (other than adding aero bars) and they can be used safely on group rides and centuries, unlike aero bars.
Tubulars vs. Clinchers
Bar none, the finest riding wheels and tires out there are tubulars. Tubular tires, also known as sew-ups, actually sew the tire casing into a tubular shape around the innertube. These tires are then glued onto special tubular-specific rims.
The combination of special tire and special tube can cut noticeable weight from a set of wheels. Because the tires retain a circular profile with only minimal distortion at the contact patch where the tire meets the ground, they corner exceedingly well. They are, however, difficult to glue on and even more difficult to change in the event of a flat. Most riders who do use them only use them on wheels reserved for racing.
Carbon Fiber Rims
In the quest to reduce weight on the bicycle, carbon fiber has been used to make rims, hubs, and in some cases, even spokes. Carbon fiber rims are available in both tubular and clincher designs, and can shave 200 grams from an already lightweight set of wheels while offering a deep-section rim profile. The combination gives riders a set of wheels with superior aerodynamics with a weight appealing to climbers: the best of both worlds, as it were.
This powerful combination comes at a price, though. Carbon fiber rims require special brake pads, crack easily (a cracked rim can fail suddenly, resulting in a crash for the rider), and don't dissipate heat as well as aluminum rims. This makes braking on long descents more hazardous, because it is possible to heat the air in the tube to the point that it expands and blows the tire off the rim. A carbon fiber rim can melt from the heat generated by braking on a long (more than 2 miles) descent. And finally, wheels built with carbon fiber rims are expensive; in most cases, expect to spend $2,000 or more.
To purchase a set of wheels, you will need to specify the type of freehub you need, which is based on the components on your bicycle. The two types are made by Campagnolo and Shimano; SRAM-made wheels use a Shimano-style freehub.