The most important piece of cycling gear. Whether required by law or not, it is the right choice to wear one. Choose a helmet that has styling that appeals to you, and check for proper fit. Most of today's helmets have an adjustable sizing mechanism that allows for quick and easy changes to the helmet's headband. A bright colored helmet increases visibility to other road and trail users and reflects sunlight while keeping you cool.
Proper hydration will make every ride easier and allow for quicker recovery. Even on cool days you need to keep drinking fluids as you ride. A basic guideline is to drink about 20 ounces of water for every hour that you ride. Depending on your body or warm temperatures, you may need to drink more than this. Water bottles attach to your bicycle with a bottle cage. Hydration packs are backpack-like accessories with a water filled bladder and a drinking tube. It is standard equipment for mountain bikers.
Protect your eyes from debris and wind borne dust. Contact wearers will need sunglasses with more coverage area. Most cycling eyewear uses polycarbonate lens material, which is highly impact resistant.
Often overlooked by new cyclists, gloves are an essential piece of cycling apparel. Most cycling gloves incorporate strategically placed padding to provide shock absorption, alleviate numbness and prevent painful calluses and blisters. They also provide hand protection in instance of a spill. Protect your hands with a good pair of cycling gloves before you hit the road or trail.
Bicycle shorts make for a more comfortable ride. They dissipate heat in hot weather, and you will greatly appreciate the chamois padding on any ride that lasts an hour or longer. Why the tight fit? The fit is more than just "part of the cycling uniform." The tight fit prevents chaffing and increases efficiency by reducing wind resistance from flapping fabric. They are very light weight too, contributing to easier climbing. Not all cycling shorts are tight. Baggy-style shorts and knickers feature padding and pockets for comfort and convenience. This style is typically preferred by mountain bikers.
Inflating your tires before every ride or every other ride is a good step in preventing flats. You will actually need two pumps--one for home and one to take with on your bicycle. Look for a pump that is compatible with your bike's valve type (Schrader or Presta). Many pumps accommodate both types.
A few tools cover most things that may need adjusting or tightening in the middle of a ride. For most bikes you need a multi-tool with 4, 5, 6mm Allen wrenches, and a Phillips head screwdriver. For off-road riding, it is best to have a chain tool, cutting blade or knife, and a flat head screwdriver as well. At least two tire levers. and a spare inner tube of the correct size and a patch kit.