mooncaps...inside and out and why
 

I have noticed some discussion on the subject of mooncaps, and whether or not to put them on the inside or outside or both. BOTH would be best and heres why. When installed on the outside they make a smooth surface that is aerodynamic and they prevent air from entering wheel. When on the inside they keep the rim spokes, etc from becoming a centrifugal pump or fan. You may not get as good of results from the inner cover as the outer cover but it will help and together they will go far....."OK kids, story's over, time for bed..."

Yeah I was wondering this, i'd have to see real tests.

My understanding is that brakes need cooling.

Even if you can get the moon caps to go on the back side of the wheel with the brake mechanism located there, that would leave the brake entirely encased. I think any serious stopping will cause overheating of the fluid (which causes brake fade), and also overheat the rotors, drums and calipers.

If anyone knows that I'm fulla beans on this, please speak up. But I do think brake cooling is important.

I'm with you. But if you wanted to put Moons or some other smoothie on the inside, you'd have to do some fabbing to make it go and still get the mounting done. If you're going to go to all that trouble, may as well work up some custom jobbies that cover unnecessary turbulators, while leaving plenty of flow around the brakes.

For hardcore hypermiling runs, it wouldn't matter. I do agree that you would need cooling. You might be able to do what formula 1 does with the wheel spats or w/e they call them.

Alright. Stop and take a deep breath.

Anyone ever looked at the backside of the wheel when it's mounted?

I can barely get my pinkie between the rim and the brake disc.

It's not a whole lot better on the drums.

I don't think there's much of anything to cover up back there in the first place, never mind the fabbing difficulty, brake cooling compromise, and dubious potential aero benefit.

Kleen Wheels Are basically a mooncap for the inside of your wheel.

I used to run those on my 90 Turbo Grand Prix. I used to get 32mpg in that car, but it was due to tuning and driving technique, I doubt the Kleen wheels helped at all.

Those are so deep within the wheel that the only effect they'd have on the airstream is whatever might be flowing from one side of the wheel to the other right?

You are correct, Frank. I never noticed any change in FE when I had them on my cars. The only thing that was noticeable was the lack of brake dust on the rims when they were installed.

I might put something like that together just cuz I don't like cleaning brake dust.