All About Windshield Wipers

Windshield wipers are an essential part of every vehicle’s safety system. Knowing how they work and when to replace them will help keep you safe in difficult driving conditions.

If you’ve ever attempted to drive in a storm without functioning windshield wipers, you probably gained a new appreciation for how vital these automotive amenities are to safety. Though wipers have been in use for 100 years, the ones we’re familiar with today have evolved considerably — in design, function and materials — from the early hand-powered versions. Here’s a look at how far wipers have come and how you can help yours provide the best visibility in even the worst weather.

How wipers work
Windshield (or windscreen) wipers first appeared on automobiles in the early 1900s. Various devices were invented to allow them to operate via speedometer cables (which meant they didn’t move when the car idled at stoplights) and vacuum-driven motors (which caused the action to vary with the speed of the car). Today’s models are typically powered by an electric motor that drives a worm gear connected to a linkage system, and we take for granted the ability to operate them at a variety of speeds whether the vehicle is moving or not.

Wipers act as squeegees when the thin rubber blades move across the glass. On most automobiles, the blades are mounted on two tandem or opposed synchronized radial arms. With the tandem system, one blade pivots from a point near the driver’s side and the other blade pivots from near the middle of the windshield. This provides the best coverage for a two-wiper system. The less-common opposed system mounts the pivot points on opposite sides of the windshield, and the wipers meet in the middle.

Until relatively recently, wiper blades were mounted to a linkage system so each arm was supported in six or eight places to ensure even pressure across the windshield. This system worked well for many years because windshields were fairly flat, but modern windshields have become more highly curved, driving the development of new beam-style blades. Beam blades have an infinite number of pressure points and are engineered for even cleaning regardless of the curvature of the windshield. These blades are standard on many new vehicles.

Beam blades offer advantages in battling winter weather. When snow or ice forms on the arms of traditional wiper blades, it can result in uneven pressure and cause streaks on the windshield. As the snow builds up, wipers may become totally ineffective. Some companies make blades with a rubber covering or boot over the mechanism that is designed to prevent slush from freezing the joints. With beam blades, however, there are no exposed linkage joints, so snow and ice buildup is less of a problem.

If you want the latest in technology (and money is no object), heated windshield wipers are an aftermarket option. Everblades heated wipers have a 12-volt heating element inside the rubber squeegee. The manufacturer claims the wipers melt ice and snow to ensure good visibility during winter storms. A set of two heated silicone-rubber blades with heated frame and wiring harness retails for $140.

Beam wipers are becoming increasingly common on new vehicles and provide better performance than standard wipers.

Prolonging wiper life
Although manufacturers claim that natural-rubber blades should last for a million or more wipes, they do wear out. Dirt and debris create nicks and cuts in the rubber, and exposure to sun and ozone cause it to harden. If wipers go unused for long periods, the rubber edges can become warped, resulting in noise when they’re finally needed. When you see streaks or hear noise, it’s time to replace the wipers. Regardless of how much you spent on them, they should typically be replaced every six to 12 months.

However, there are products that claim to offer enhanced performance and longer life. For example, Trico teamed up with DuPont to create a blade that incorporates a Teflon-resin wiping edge, which they claim dramatically reduces friction and enhances weatherproofing. Other manufacturers of silicone blades claim their products are resistant to UV rays and ozone, and some companies offer warranties for the lifetime of the vehicle. Silicone wipers supposedly leave a coating of silicone on the windshield each time they are used, which makes the glass slippery so the wipers wear less and are quieter. These blades are usually referred to as “silicone rubber,” but the product is actually a rubberlike material and does not incorporate organic rubber.

Standard wipers use springs to apply pressure to the squeegee and are more prone to leave streaks than newer beam wipers.

Whatever type of wipers you choose, cleaning the windshield on a regular basis will help to prolong their life. Using washer fluid to clean the blade until all dirt is removed is also helpful. Because rear windows get dirty quickly, it’s important to clean them often if a rear wiper is installed.

Another wiper-saving step is to apply a product such as Rain-X to the windshield every few months. Rain-X makes the glass slicker and reduces friction. In light rain at highway speeds, most of the water just blows off the windshield, and the wipers aren’t needed.

Replacing wipers
In general, replacing wipers is not a difficult task. You may need a screwdriver to loosen tabs or remove connectors, depending on the locking system used on your car. The new wipers’ package will provide rudimentary installation instructions and may even offer a toll-free phone number if you need assistance. (Adapters are included to fit the wiper arms used on most cars manufactured after 1998.) If you need help, you can find an abundance of information on the Internet.

It’s commonly recommended that you replace the complete wiper blade when the rubber is worn because the metal parts of the blade also experience wear and may even rust. However, to save money, some drivers prefer to replace only the rubber inserts. Inserts are available for some wipers, but not all. If you use inserts, is important that the refill be an exact replacement by the same brand — substitutions can result in subpar performance.