I was driving my new Fit on rural gravel road during modest rain today, and couldn't believe the amount of mud splatter that got got onto the back hatch.

Due to small potholes I was driving maybe 40 km/h (25 mph). At first I though my rear defroster wasn't working since my rear window wouldn't clear up. On a whim I hit the rear wipers and the it cleared a swathe of brown water! As I drove on it soon got cloudy with muddy water again.

At my next top I took a look and was shocked to see the amount of muddy water that had spattered onto the rear hatch and some had pooled on the rear bumper. The spatter didn't get onto the roof at all.

I have front splash guards but no rear ones. Is this a common issue on hatchbacks? I can't even figure out how the muddy water can be thrown up to cover just the rear hatch surface...

 

Here in the Thumb of Michigan we have lots of unpaved roads. It is always easy to spot those that live on gravel. Just look for the tan muck on the back of the any SUV, Minivan or hatch back with a flat back. The air just swirls at the back of these vehicles and brings the crud from the road up to the hatch.

We used to call this the Station Wagon Effect. If you are old enough to remember an actual station wagon like the Ford LTD Country Squire, there were seats that flipped out of the spare tire hatch and you could put an additional 4 kids back there. If you roll down the rear glass on the tailgate while the car was moving the exhaust would get sucked into the back.

I get the same thing with my boat at certian speeds. Even with underwater exhaust, the flat back of the boat causes the same thing.

For those of you who want to see real station wagon check this link Genuine fake wood grain vinyl stickers on the side. The "wood" trim around the "wood" was metal and always dented. Classic 1978 Ford LTD Country Squire 4-Door Station Wagon 10 Pass for sale in Akron, Ohio

 

^^^ that thing is a beast

 

The closest thing we get now is the Dodge Manum. Nice car, but WOW you can spend over 40K on one.

 

Thanks for the insight. I've seen this wake effect simulated on transport trucks in a wind tunnel, but didn't make the connection to the splatter on my Fit (and wow is it dirty now .

I suppose this means the Fit loses a smidge of fuel efficiency due to the straight back's higher aerodynamic drag.

 

That Wagon is sexy. I want.

And yeah, the road into my complex's parking lot is gravel and has a HUGE dual pothole (two huge ones with a bit of raised between them) and I try not to park there if I don't have to. If I just washed it, I avoid it like the plague.