---Wheel Cover Question---

[firesice18]

So I have been doing some research on wheel covers and have found research that shows that with 16" wheel covers (pizza pans) there was a proven improvement in fuel economy (@ 65mph) of about 4.6%.

Now here is my question, "Is this directly related to rim size?"

I understand that the shape and design of the rim itself will yield a certain degree of positive gain but what is the yield for rim size?

SO, I have a 2004 Nissan Maxima SE and I drive about 60 miles of highway DAILY. I also have 18" rims (not hubcaps). If I put on some 18" wheel covers, how much more gain would I see?

Is there anyway to calculate this, like per inch of size difference?

[Vekke]

I would say that there is no formula, because your rim design also dictates the results you will see. If you compare similar rims then you would see the difference between rim sizes, but even then the rim width changes so they are not 100% comparable. Anyway the gain is definetely more with bigger wheels. First you should show what your rims look before anyone can give even some estimation...

[euromodder]

Originally Posted by firesice18

Is there anyway to calculate this, like per inch of size difference?

No.
It's just a matter of trying and seeing what it'll do for your car.
It depends too much on how much air is going through the wheels ; on the wheel design itself; on the general aerodynamic design of the front of the car and the engine bay exhaust.

Bigger wheels fill the wheel arcs better.
If you then cover the open areas of the rims, you've covered almost the entire wheel arc.

[aerohead]

Originally Posted by firesice18

So I have been doing some research on wheel covers and have found research that shows that with 16" wheel covers (pizza pans) there was a proven improvement in fuel economy (@ 65mph) of about 4.6%.

Now here is my question, "Is this directly related to rim size?"

I understand that the shape and design of the rim itself will yield a certain degree of positive gain but what is the yield for rim size?

SO, I have a 2004 Nissan Maxima SE and I drive about 60 miles of highway DAILY. I also have 18" rims (not hubcaps). If I put on some 18" wheel covers, how much more gain would I see?

Is there anyway to calculate this, like per inch of size difference?

I think it's a non-dimensional issue, as size just follows scaling,Wheel covers on a toy car would generate the same effect in full-scale.
In the 'mod-data' sticky there are some hard numbers on wheel covers.

[MGB=MPG]

would these work as good as pizza pans ?
i need to search for the data , 4% sounds nice
Experiment: smooth wheel discs tested A-B-A - 4.6% mpg improvement @ 65 mph

baby moons



16 inch moons on this machine
Hubcaps Wheel Covers | Hubcap Mike's | Buy New Hub Caps Online

[firesice18]

Would a cloth cover yield the same type of gain as a metal or solid material cover? Something tightly and evenly stretched over the rim, not just some home made crap. Ideas?

[euromodder]

Yes, the convex shape apparently is even beneficial.

If they stay on, that is.
Hub caps have a tendency to part ways with the wheels.

[euromodder]

Originally Posted by firesice18

Would a cloth cover yield the same type of gain as a metal or solid material cover? Something tightly and evenly stretched over the rim, not just some home made crap. Ideas?

These are being used over the spoked wheels on velomobiles (covered recumbent cycles)

The fabric needs to be (made) windproof though.

[cfg83]

euromodder -

Originally Posted by euromodder

Yes, the convex shape apparently is even beneficial.

If they stay on, that is.
Hub caps have a tendency to part ways with the wheels.

Yes, that is my experience, especially with the style that has those little "grabby" teeth around the edge. Over time the teeth will fatigue. They also make scritch-scritch sounds against that steel wheel as you drive, which could get on your nerves.

CarloSW2

[MGB=MPG]

smoothie wheel covers installed