Why don't sedans have a rear windshield wiper?

Question

I notice only minivans, SUV's, station wagons, and hatchbacks have rear windshield wipers, while sedans don't. Why? The snow and rain probably actually accumulates on a sedan's rear windshield because it's almost horizontal, so why don't they have a wiper? What is the need to have them on other...

Answer 1

The reason sedan don't have rear wipers is because of aerodynamics.

The rear windows, which is like mostly vertical, doesn't get that much rain, because you're driving FORWARD. Very little water actually land on rear window. There's also rain-run-off channels on the roof of the car to "guide" the water away from the top of the roof, then out to the sides. The roof is actually curved, like the road. So most water don't even runoff to the rear windows.

And another factor is the trunk itself, which helps move air along and not circling around the rear window, trapping dirt and rain. Air flows past the roof and flies for a bit then drops onto the trunk. There's a bit of a "vacuum" near the rear window, but not enough.

Hatchbacks, with sharply raked windows, have much bigger surface area so rain can drop onto the rear window itself. There is also no 'trunk' to guide the airflow. All of the air flows right at the surface of the window, so it does need rear wipers.

SUVs/wagons with window right at the rear has nearly vertical windows, but not the trunk to guide the airflow. It has a low-pressure zone right in that area when it's moving at speed, which will "suck in" water and dirt and thus make the window very dirty. Wiper's not for the rain, but rather for the dirt (so it also has washer nozzles)

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Kasey C, PC guru since Apple II days
We have enough youth, how about a fountain of SMART?

Answer 2

Rear Windshield Wiper

Answer 3

Back in the day, vehicles like sedans and SUV's had wipers in the back for convenience but most places have bastard kids and gangs and all sort of trash. They would break them or removed them which cost a lot of money to replace, so the car companies thought of this "Defoggers." These metal lines would transmit heat through the rear windows which will defrost windows and cause water to move. Then they notice it can be expensive just as well and perhaps dangerous which they stopped on most newer cars. Both these methods would make the cars even more expensive for a luxury that has been replaced with something cheaper. Air.

They now put air vents by the rear of the car with a nob in the front to defrost windows either with cold or warm air.

However, there are still companies that DO still install the metal strings on the rear and wipers too, but they not cost efficient so you'll hardly find them on newer cars. Though Vans, Trucks, and Station Wagons still have them installed or not.

Answer 4

I have wondered that too actually, I think it may be because on the outer sides of the rear windshield it is a bit curved, actually the whole thing (on most sedans) is slightly curved, so a wiper wouldn't be making direct contact throughout, which obviously wouldn't wipe away rain. I'm just guessing, good question though.

Answer 5

no good way to mount it on a sedan that wouldn't cause water to accumulate around the wiper arm and thus leading to rust and or leaking.......

also the aerodynamics of a sedan force air down the rear windshield and this would rip off a wiper at higher speeds ......

not to mention a rear wiper on a sedan would sling water onto passing cars due to aerodynamics...

also due to air flow rear wipers aren't needed on rear windshields as much......

Answer 6

With all the tech around tis there really not a way to put wipers on rear windows on all sedans, in heavy rain driving in city traffic is when you really need a clean rear window. Your side mirrors are wreaked with rain, they become useless, your back window is basically blind from all the rain,so how do you check the traffic behind you on red lights, stop signs and uncontrolled intersections ?? The no.1 collision in city traffic, you guessed it, is rear end collisions. I teach my driver ed students, that every time your foot moves to the brake pedal, or you know you are going to slow down soon, your eyes go to your mirrors, hard to see anything in heavy rain storms, safety is now a monumental factor, vehicles in the flow of traffic and pedestrians scurrying across streets in a rain storm. Come on auto manufacturers, you claim safety is one your large factors in selling new vehicles, well it is time to make them even safer.

Thanks

Driver ed instructor with many years of experience.

Answer 7

actualy, the road spray and mist doesn't reach the back window while driving. and i had an older sedan, that actually had a rear wiper, but i rearly used it, if i did to clean my window, not to actualy use it as a rain-wiper

Answer 8

Hello. My rear wiper sedan built. Very beautiful and interesting.

Answer 9

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Answer 10

The aerodynamics of the car wipes water off of the front windshield (usually). It is also cheaper to not have a wiper there.