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This is going to be a short description on how to make flat aerodynamic wheel covers.

I'm making these because the rounded ones from Hubcap Mike sick out too far for my rear wheel skirts. So I needed to buy or make some flat ones. Unfortunately I could not find any thing locally to buy and modify so I had to make my own.

First you will need a sheet of aluminum from Lows or other hardware store. I would recommend getting the largest you can find that will fit 4 16" covers. The sheet I found was 48" long by 24" wide by .025 thick. This allows for 3 caps. They had smaller sheets but they would only fit 1 cap so you may have to buy one large sheet and one small sheet. The large sheet was $42.88 and the smaller ones were $22 something.

I also had to buy some tin snips. My receipt said they were 9 3/4" 'R' Metalmaster.

To make the brushed aluminum look I bought a Sand Blaster sanding sponge coarse 60.

You will also need some 3M double sided adhesive tape.

Some aluminum polish will also help a lot to make the caps look pretty.

I also used the extra aluminum rivets I had from my other wheel cover installation.

I'll try my best to describe the process because I did not take very many pictures.

First off take a trim ring and lay it on the aluminum sheet. If you use the larger sheet to get three caps on it you will need to position the the trim rings with one at the top corner, then draw a circle around it with a magic marker. Then position the trim ring next to the first one you traced out near the bottom, then the next trace will be at the top. I had to cut on the inside of the marker trace then cut an additional 1/16" all around to get it to fit the trim ring. I then filed everything down smooth so I would not cut myself.
http://stuff.jaygroh.com/priuschat/flatcap/cutout.jpg


Once you get the caps cut out you need to find a way to brush them to make them pretty. Since I don't have the right tools for the job I decided to use my prius as a lathe to turn the discs to get that pretty brushed aluminum look. To do that I had to mount the discs temporarily to the trim rings using the 3M sticky tape.
http://stuff.jaygroh.com/priuschat/flatcap/stick.jpg

Then I attached the the whole thing to the front wheel of the prius. Now in order to get the front wheel to spin you must disable traction control. To find out how to do that just do some searching on "disable prius traction control" and you will find it. After the little dance is done I jacked up the side of the car until the wheel came off the ground. I then put the car in drive and the wheel started to spin at the normal 7mph. (NOTE: During this process the odometer will continue to advance just like the car was moving down the road. I was able to get one cap done in about .5 miles. So expect your odometer to read about 2 miles greater after your done brushing the aluminum.) I first brushed the aluminum with the sanding pad, then used polish, then wipe the polish off, then another final brush with the sanding pad. This gave a nice clean look almost matching the caps from Hubcap Mike. :D

Here is the before.
http://stuff.jaygroh.com/priuschat/flatcap/before.jpg


Here is the after.
http://stuff.jaygroh.com/priuschat/flatcap/after.jpg


Here is a side by side. My flat cap on the left and Hubcap Mike's round cap on the right.
http://stuff.jaygroh.com/priuschat/flatcap/compare.jpg


I used a putty knife to remove the discs from the trim rings.
http://stuff.jaygroh.com/priuschat/flatcap/separate.jpg


Here is the video showing how I brushed the discs. Video is 2x speed.
How to make a brushed aluminum aerodynamic flat wheel cover for a Prius (http://video.google.com/videoplay?docid=428497399714999524)


Now I just need to align the cover onto the ring and start drilling holes. I used masking tape to keep the disc in place while drilling.
http://stuff.jaygroh.com/priuschat/flatcap/tape.jpg


I drilled and riveted at the center of the flat spots in the location you see below.
http://stuff.jaygroh.com/priuschat/flatcap/rivet.jpg


Next I drilled a small hole where the valve stem would be. Then drilled a bigger hole, then and even bigger hole. Then I used a dremel to sand out an even bigger hole and smoothed out the edges. The result is what you see here. This is the finished product.
http://stuff.jaygroh.com/priuschat/flatcap/done.jpg


And here is what it looks like mounted on the car with the wheel skirts. My flat caps are on the rear wheels under the skirts and I'm using Hubcap Mike's caps on the front wheels.
http://stuff.jaygroh.com/priuschat/wheelskirts/skirt32.jpg



I think I will have to buy some valve stem extensions to make it easier to fill the tires up with air. The holes are just big enough to fit my air compressor end into. Of course if you dont have wheel skirts you may not want to drill a hole to check the air pressure as the cover/trim rings are easy to pop off with a screw driver or plastic panel removal tool.

Hi Jay:

___Where do you work to have access to all the goodies in drawers and machining toys to play with :D

___I always wanted to see a flat disc vs. that one with the bowed tip and when you have perfected its production, attachment and weight, let us do a Group Buy!

http://video.google.com/googleplayer.swf?docid=428497399714999524

___Good Luck

___Wayne

Thats my parents garage. My dad has collected nuts, bolts, screws, crap for many years.

No need to sue anyone to get the wheel to spin. All you have to do is the macarena in the drivers seat. ;)

Group buys are fine but the group will have to make them themselves. :p

I updated my first post.


Also how do you embed the google video? I thought the forum software took care of that automatically?

Great job. They really look good and help set your Prius apart from the rest. After seeing your car last year, I have thought about making some for mine.

Have you ever given any thought to using plastic? I know it would'nt have the brushed aluminum look. I have a cnc that I could use to cut them out in no time, and was thinking about trying to find some cool looking plastic to use.

Hi Jay:

___I thought you might like to see this form the Honda Clarity as they changed the wheels and backing plates for better aero since LA last year…

http://www.cleanmpg.com/photos/data/501/Clarity_aero_wheel_setup.jpg

___Good Luck

___Wayne

Jay,

Did you make any before and after measurements so that you can measure the impact of the aero changes???

Hi All,

I have a different way of making aero-wheel covers, using the Prius trim rings. Its been posted a couple places. I used 10 mil thick aluminum flashing. Seems to be sufficiently durable. Altho, its not sufficiently stiff to put a brushed finish on. I just waxed em up good. I nibbled out triangules between about 3/4 inch long tabs, which are folded over the edge of the trim ring. The trim ring normally has clearance to the wheel, which the alumimun flashing fills, and thus there is a good clamping action on the flashing tabs.

Recently, I it was time to go get the tires rotated and balanced. I popped off the rims and cleaned them and the rims up, since they had been on there since late December. Then I did a few coasting tests. Which is difficult in a Prius. I found a hill I could crest at 35 mph, go into neutral, and then coast down getting up to about 45 mph at the bottom. With the Mycanscan .1 mph speed resolution, 45 mph was fast enough to see a difference. At the bottom of the hill I would watch the speed peak, and then on the very next measurement cycle speed would decrease by .1 mph or more without the aero-hub caps. With the hubcaps the speed peaks, and then stays constant for 3 or 4 measurements cycles. The cycles were about 1 second long.

I read about people doing a pulse and slowing glide in SHM. Most of the time I can lock into 53 mph, and 1280 rpm and go on forever on a flat road. There really is no pulsing needed until an upgrade is involved. This may be due to the aero hub caps.

Great Job Jay. I had these on my chopped 36, 2 dr. Ford, in the 60's. Not sure, but you may still be able to get these at a Hot Rod retail store? H

Jay,

Did you make any before and after measurements so that you can measure the impact of the aero changes???

I plan on doing that when I have time. I'll do all off first, then all caps, then caps plus skirts, then all off again.

Great job. They really look good and help set your Prius apart from the rest. After seeing your car last year, I have thought about making some for mine.

Have you ever given any thought to using plastic? I know it would'nt have the brushed aluminum look. I have a cnc that I could use to cut them out in no time, and was thinking about trying to find some cool looking plastic to use.

Plastic would be nice and easy to work with but I like that brushed aluminum look. :D

Great Job Jay. I had these on my chopped 36, 2 dr. Ford, in the 60's. Not sure, but you may still be able to get these at a Hot Rod retail store? H

You can get the rounded caps from Hubcap Mike (http://www.hubcapmike.com/rdc02-15.html). These caps are round and not flat which should make them more aerodynamic. The only reason I made these flat caps is because the rounded ones from Mike would not fit underneath my wheel skirts.


Also in the last picture you see I'm using my flat caps in the rear under the skirts and Mike's caps up on the front wheels. I'll update the text above the picture to point that out.

More satisfaction when you make them yourself as well. The car looks great. I would try this on my HCH2 as well but the pie plates are close enough. H

Great job, but I think you can buy them from J C Whitney still!