Aerodynamic wheel fairings/mudguards/housings

[Vekke]

Hi,

As you propably have noticed I am building my next fuel sipper and its gonna be bad ass ride.

What I havent yet seen in any tests or talks is that you put spare wheel cover on top of your wheels.

In general the less aerodynamic drag you will have smaller the wheel housing volume is. Easiest way to get most smallest volume is put wheel housings on top of your wheels.

So my plan is to use this kind of housings:


Cut them to correct shape and attach over each wheel.
- Front wheel can still turn without any problems.
- Tire housing volume is minimal, I am shooting for 15-20mm gap to tire
- They could actually look cool and futuristic
- Tire vortices should have minimal effect to aero

Now those wont fit in place on most cars but the A8 has quite big room there specially with smaller diameter tires which was one of the reasons to move 195/65R15 size.

[Hersbird]

I think you will hit a bump or turn hard and the sidewall will flex enough to rub and grab the tire at speed. I think you are talking about mounting them to the spindle and then cutting out a bottom chunk for the contact patch of the tire. The 1969 Plymouth Roadrunner had some promo discs that worked that way just covering the wheel and none of the tire. I don't think this would work on a car w/o a stationary spindle but there are some spinner type wheels that use bearings to create a stationary center piece rather then the normal spinning center piece. here is the Roadrunner in action

https://www.youtube.com/watch?v=EBcRIRYWRHM

[BamZipPow]

The Plymouth is using a product similar to CapAds...
http://www.capads.com/

[BamZipPow]

11 years ago AdFleet rolled out a similar product....
Have You Seen These Wheel Cover Ads? - Motor Trend News

[Vekke]

No not like that, like this:


So only wheels will roll/rotate these will turn along tires in the front and follow suspension. When painted to body color will look better IMO than hubcaps. You can still intall hubcaps under that cover, but effect will propably be neglible to none.

I think these should save over 5% of fuel?

[razordave]

All tires bulge with heat. You'll also have to mount that thing on there really well (x4) then you have issues with checking your pressure and making sure there are no general problems with the tire.

If you can make this work, I'd highly suggest weekly removal for inspection which is something you should keep in mind while figuring out a mounting situation.

[Joris]

Great idea, if you can make a sturdy bracket/baseplate on the struttower and keep enough space between wheel and cover there should be no problems right? Try keeping the unsprung weight low.

[Vekke]

Yes metal brackets etc will be needed. I have ligthened the unsprung masses about 11kg per front corner so little bit more back is not that much big problem. That inside will still be open and heat should not be a problem anyway in finnish climate and with my driving style. Structure migth be problem in winter when snow fills that volume and freezes and when it got loose its solid ice block. So will not work in winter propably, but time will tell.

Basicly there should not be no problems but I am trying to get more data is closer the tire better clearance like I have read from aerodynamic books...

[Ecky]

Great idea, and just what I've been looking for.

[freebeard]

Keep in mind:

The difference between theory and practice is less in theory than it is in practice.

The Ford Probe IV Concept did the same thing with a flexible, deforming skirt over the wheelwell opening.


Have you ever seen a slingshot drag racer spin the tires at the starting line? Admittedly they're low-pressure bias-ply tires, but they grow 3 or 4 inches in diameter before the car starts to move. The whole rear of the car raises up.

That said; go for it.