Be ready to be safe

Few people would choose to ride in a car with no seat belts. So why hop on a bike without a bike helmet? Helmets simply make sense in all riding conditions, particularly since at least 21 states carry laws requiring them.

Helmets have grown more style-conscious, typically provide superb ventilation and in most cases weigh less than the omelet you had for breakfast—all of which makes it tough for anyone to dream up an excuse for not wearing one. Here are some tips for choosing a model well-suited to your needs.

Which Type? Sport, Road or Mountain?

Cycling helmets come in 3 basic styles—sport, road and mountain bike helmets. All types are designed to protect riders from impact while being light, comfortable and stylish.

• Sport helmets ($35-$55): Economical models that work well for commuter, road and mountain bikers as well as skateboarders and inline skaters.
• Road bike helmets ($60-$230): Their appeal lies in their low weight, generous ventilation and aerodynamic design.
• Mountain bike helmets ($50-$130): Built to offer maximum protection from trailside obstacles. Typically these helmets include visors and more extensive rear-head coverage. Special retention systems provide a firm and secure fit on rough terrain. Cyclocross riders often seek out these helmets.

Find the Right Size

A good fit is vital. Sport helmets many times simply offer a single, adjustable size. In other categories, helmets come in small, medium, large or extended sizes.

To determine your size, wrap a flexible tape measure around the largest portion of your head—about 1 inch above your eyebrows. Or, wrap a string or ribbon around your head, then measure the length of string with a straight-edge ruler or yardstick. Look for a helmet that matches your measurement.

Manufacturers sometimes vary in their interpretation of what dimensions are encompassed by the terms small, medium and large. Your best guide: Use the numbers shown on the "Description" tab for individual products on REI.com. There are also some general parameters for adults below.

• Small: 20"-21.75" (51cm-55cm)
• Medium: 21.75"-23.25" (55cm-59cm)
• Large: 23.25"-24.75" (59cm-63cm)
• Extra-small, extra-large: Below 20" (51cm), above 24.75 (63cm)
• One size fits all (men): 21.25"-24" (54cm-61cm)
• One size fits all (women): 19.75"-22.5" (50cm-57cm)

Most children's helmets are one-size-fits-all variety with a range of 18"-22.5" (46cm-57cm).

What if you are right on the border between sizes? The general advice is to choose the smaller size.

When to Replace a Helmet

Any time your helmet is involved in an accident, it's likely to get damaged. Since damage isn't always easy to spot visually, replace the helmet after any significant impact, even if everything "looks" OK. It is generally recommended that a helmet be replaced after 5 years, even if it has remained crash-free. Pollution, UV light and weathering can potentially weaken its components over time.

A few helmet tips:

• If your helmet includes an owner's manual, read it before your first ride.
• Avoid using chemical solvents to clean a helmet. Manufacturers recommend only the use of a soft cloth or sponge, plus mild soap and water.
• Do not store a helmet in an attic, garage, car trunk or other area where heat can accumulate. Excessive heat may cause bubbles to form on helmet parts. Do not wear a heat-damaged helmet.
• Avoid loaning your helmet to others. As a savvy rider, you want to know exactly what kind of treatment your helmet has experienced during its entire lifespan so you can knowledgeably assess its integrity over time.