I've Got It!!!!!!!!!!!!!!!!!!!!! You Gotta See This!!!
 

I was on my way home from the chiropractor today and a garbage truck went by at a light. HE HAD WHAT WE CALL FRONT WHEEL SKIRTS!!!!! But get this, they were made of stiff bristles so the wheel could go through them and he could turn but at high speed when his wheels were straight ahead they kept the air out of his wheel wells!!! The green is where he had the bristles and the blue is what might work on the rear of a wheel well, if the bristles are stiff enough. the whole bunch of bristles was at least 3/8 inch thick. let me know what you think. SEE PIC

Attachment 3940

Something about that photo seems fake :D

Unfortunately, there are considerable pressure differences across a wheel skirt, so you'd need good sealing between the bristles.

I believe those are mud flaps. If they were dense enough but still flexible enough to let the tire turn, might work.

A garbage truck wouldn't really benefit from aero mods anyway. That thing probably spends most of its time at less than 10mph.

That's likely to have been installed to reduce the amount of water spray being kicked up when driving on wet roads. If you watch any vehicle (other than mine) driving down a wet road, you can see the water mist boiling out of both wheel well openings.

I was thinking something like constant tire cleaning. I believe that's what WM said about them the last time I applied for a job there.

I would imagine it scrapes garbage off the tires too.

its the principle that i am trying to get at here.
 

The problem with putting front wheel skirts on a car is that the front wheels stick WAY out when you turn so it is a problem. I was not implying that he used it as a wheel skirt but that if the bristles were on a car and went all the way around the top of the tire that it would make a very nice wheel skirt that would not be damaged when you turned a corner. and i was unable to see through the bristles, VERY dense. Functional and neat looking.

Still, at high speeds, they'd probably deflect in the wind anyway, and might make an otherwise somewhat clean area become very aerodynamically dirty. Unlikely, but we can't say for sure that it won't happen, at least without proper testing.

So - You gonna screw some push brooms to your fenders?

The skeptic in me says they wouldn't work for aero reduction.

But then it wouldn't be fair to say one way or another without a decent investigation.

I am seriously thinking about taking a broom with VERY stiff bristles
 

and cutting them off so i can sandwich them between two bent pieces of aluminum with epoxy and trying that but it will be a lot of work so i will probably put it on a back burner and do some of the other things i have planned, like a v-shaped air dam.

lol that is NOT an aeromod...it is a wheel brush and water guard lol

Well I think if you wanted to make front wheel skirts you need to get new front tires, same height but skinnier that the stock ones so that the flair your going to have to put on the skirts for turning can be closer to the vehicle.

air has to pass over and around an aero mod, not weave in and out through it

You can put 195 tires on 13x6 rims with a 42mm offset and 4" backspacing. You can also put 165 tires on 13x6 rims with a 42mm offset and 4" backspacing. Either way, you'll have nearly the same distance between the fender and widest point of the wheel rim. (Yes, it's a wheel rim, or outer most section of the circumference of the wheel.)

The gap between the fender and wheel is more a function of offset and backspacing than anything else. Skinnier tires won't cut it for you any differently.

I've seen those bristles on the front of city buses. I guessed they mostly are to keep water spray down, but the thought of using something similar as partial front skirts has crossed my mind. I do wonder, though, how it would work at highway speeds. Maybe just at the front of the wheel well?

The problem with the idea is the abstract of it overall. For the amount of time you'd spend trying to figure out how it would work, and whether it would work at all, you'd be hard pressed to not just install a solid partial skirt from the bumper and upper fender area to cover and slightly exceed the area in front of the tire.

I like the principle of the idea. I'm not sure bristles are good enough at blocking air, but what about plates of rubber or flexible plastic? Stiff enough that it doesn't flap violently in the breeze, soft enough not to damage a tire when you hit a pothole while turning. Maybe even partial spandex wheel skirts with a flexible wire frame for support. A wheel skirt doesn't need to cover the whole wheelarch, just the gap between the fender and the tire.

I think that the problem is that wind at highway speeds is as strong or stronger than the force it would take for the bristles to bend for the tire. This means that anything that isn't supposed to rub really hard on the tire will start to bend at 70+MPH. I think staying with the broom bristles is the best bet, I mean that they might be the most immune to bending at speed, since the air can go around them. A solid piece of material will have a relatively large area, so once it starts to flap or bend in the wind it's toast.

This idea is OK for buses and city trucks that don't exceed 45MPH.

See page 16 of this study.

http://www.aaafoundation.org/pdf/SplashSpray.pdf

I don't think air leakage through the bristles would be that much of a concern. Like a mesh c-band dish, it doesn't take much wind speed before it ends up acting like a solid dish anyway. I think the bristles would be stiffer in wind than rubber belting.