Writing "stay cool" in a friend's yearbook can remind them that even after high school ends, they should keep their body temperature below 104 degrees to avoid total organ shutdown. Have a cool summer with this Groupon.
Choose from Three Options
- $12 for one all-day bike rental for one person with helmet ($20 value)
- $45 for one Friday–Monday 6’x15’ floater-mat rental ($79 value)
- $49 for one Friday–Monday inflatable-standup-paddleboard rental ($99 value)
Five Things to Know About Bike HelmetsMake sure to don a helmet before pedaling away. Read on to learn more about this lifesaving headgear.
1. Helmets are designed to absorb the shock of a sudden impact—not necessarily break a fall. During an impact, the energy disperses across the polystyrene shell of the helmet instead of inside your fragile skull. The shell even is designed to break to help reduce the force on the wearer.
2. Bike helmets are sporty adaptations of motorcycle helmets. By the time specialized bike helmets emerged until the 1970s, motorcyclists already had been sporting polystyrene helmets for years. Bicyclists would be perfectly safe donning motorcycle helmets, of course, but they’d find them both heavy and sweaty. Bicycle helmets are lightweight and designed with ventilation to keep heads cool.
3. Safety isn’t guaranteed. Despite rigorous testing standards, no helmet is sure to respond well to every possible form of impact. In general, helmets perform best during impacts against flat surfaces, where the curved, flexible shell can more easily disperse the force.
4. Don’t forget about fit. No matter how sturdy a helmet is built, it can’t protect you if it doesn’t fit correctly. The helmet should sit low on your forehead, so that you can just see the brim in your upper range of vision, and the chin straps should hold the helmet firmly and securely in place.
5. "Invisible" helmets may be the future. The design of the bicycle helmet has been rather static for the last 40 years. But in 2013, Swedish inventors debuted the [Hövding](http://www.hovding.com/en/), an airbag-like inflatable cushion that sits within an obtrusive collar and deploys just before impact, saving lives otherwise ruined by a constant display of helmet hair.