TechKnow: The science of winter wipers
Innocuous but essential, winter wiper blades are more common sense than industry standard. Either way, there's quite a lot of science involved in their manufacture. Anthony Jackson explains.
Posted November 16, 2010
By ANTHONY JACKSON, EVERGEEK MEDIA
This time of year rolls around and everyone from your neighbor to your dentist has reminded you to get your winter tires on. Maybe they're being helpful, maybe it's just small talk, or maybe they don't want you crashing into their Santa display at the curb. So yeah, winter tires. You've put them on, right?
Some of us do this as a matter of routine and think nothing of diligently heading down to our local tire dealer and getting the annual job done each fall. Winter’s here, need winter tires. A no brainer. But there's something else you should swap out for winter, something so important that without them working properly, winter driving is virtually impossible. Wiper blades. Check.
These modest strips of rubber that you stare at through the windshield every day are the backwater of automotive technology. If you could magically transport an average car driver from 1930 to 2010, the one feature on cars that would look virtually unchanged would be the wipers.
But the things have changed on a subtle level, in fact, and continue to change with the adoption new designs and new materials. But this often overlooked safety feature isn't something you necessarily swap out like tire, depend on what's working for you already.
Inspecting your wipers regularly should be a part of your regular maintenance; change the oil, check the tires, inspect the blades. Nothing is going to be of a higher priority while driving than actually seeing out of the window, especially during the winter months. The dirt and gravel kicked up on to your screen can be a serious year round hazard, but combine this with snow, ice and an early sunset and you have a drive home that can make Clint Eastwood's The Gauntlet look like a cake walk.
Winter blades - as opposed to regular blades or "all season blades" if there were such a delineation - are not that new in concept. One of the biggest manufacturers of all blades, Trico, first introduced a winter model way back in 1953. The company continues to market a full line of winter-ready wipers today, the "Chill" series. Essentially, these are conventional wipers with a latticework spread out to hold the blade's length to the arm at its center, except with a rubber boot fitted around the works, thus preventing snow and related wintery gunk from clogging the mechanism.
This latticework, common to many blades, is actually a series of whippletrees designed pivot over an arc and distribute force. If the snow clogs up the whippletrees, force is not evenly distributed across the windshield, leading to patches of un-wiped glass.
Unlike tires, there is no industry standard for what makes a wiper blade a winter wiper blade. In terms of the traditional wiper and the so-called "winter wiper," you're usually talking a sturdier frame, an anti clogging boot and sometimes tougher rubber, but they're still virtually unchanged from the wipers of fifty years ago.
You can swap them out seasonally, as winter blades are bulky - and downright ostentatious if you drive a sporty little car - and they wear out like regular blades but cost more, so using them only when needed - in winter - is common, like winter tires.
In recent years, however, many manufacturers have moved from rubber to silicone as the material of choice for the wiping edge. Silicon tends to increase lifespan and deliver superior cleaning of all types of windscreen residue, from water to mud and particulates and even ice. There has been such a shift to this type of material that most premium blades now only come in silicone, or with some silicone component and sometimes that no-stick wonder, Teflon.
Another development is the move away from traditional lattice arm wipers with multiple moving parts (whippletrees) to a "beam" or "flex" type wiper. These consists of a sprung, flat rod, usually made of metal incased in plastic with the wiping blade protruding from the underside. Most manufacturers have adopted this newer design over the last few years, each with their own product line sporting beefcake names like "Reflex," "Edge" and "PrecisionFit." This reinvention of the humble wiper has many advantages, particularly for winter driving.
As beam wipers do not have the latticework that clogs with snow, they can maintain even pressure to the blade across the span of the wiper in all conditions. With no pivoting parts beyond the universal wiper arm (the part attached to the car and wiper motor) and a silicone edge, beam blades are much less likely to stick to the windscreen or be compromised by ice. Silicone is less porous and therefore absorbs less water; harder for ice to take hold. It also retains its properties at a lower temperature range than rubber, down to -50C. In any season, beam blades also benefit from less buffeting in high winds or cross winds thanks to a much lower profile. And finally, silicone does not degrade under UV as rapidly as conventional rubber.
It should come as no surprise that technologically advanced "premium" blades come at a premium price, two or three times as much as a regular replacement blade. $50 a pair is not uncommon, though the consistently clear view they provide should be considered priceless.
If that's not winter-enabled enough, you can even go a stage further and install heated wipers such as those from Everblades out of Michigan (a State known for its Canadian winters). Bear in mind that this type of upgrade isn't as simple as swapping out a pair as you have to wire them into your car's electrical system. Nevertheless, they are very effective and work by physically warming the silicone blade to melt ice and snow and then shoving it aside like rainwater. These aren't cheap, mind you. They start at $120.00 a pair!
The importance of good quality washer fluid should also be noted as a winter driving essential. Always use a product rated down to at least -40C. Even if you're sure temperatures in your region will never get that low, you should be accounting for wind chill, in which case -40C is possible if not likely. Besides, a cheaper -20C washer fluid might as well be paint on the one day it hits -21C. Nothing wrong with a bit of overkill in that department. Also, carry a spare jug of the stuff, especially for long trips, but even short ones because Murphy's Law states you'll never run out of washer fluid in the garage, only out there on the road.
And it should go without saying, but not using the right washer fluid will pretty much make good quality wipers useless in any conditions. Sweeping accumulated snow off the windshield before you set out is also wise, as even ultra-premium blades aren't going to help wiper motors to pretend they're snow plows.
With winter tires you have to compromise, what works well in winter does not work so well in summer and vice versa. Thanks to recent developments in wiper technology, the advent of the silicone blades and beam design, you can now buck up for a long-lasting wiper that performs just as well in winter as in summer; the days of having dedicated winter wipers may be numbered... if you ever thought to number them in the first place, that is.