Aero-AntiCorrosion Mod to Trim Rings..

[donee]

Hi All,

Who says the Trim Rings on the 15 Inch wheels are useless? Here is a mod to cover up the disk brakes from melting snow and rain when parked. They also should help aerodynamics, but I have not tested them for that. This mod may not be too durable, but so far so good.



This were made using .009" thick 20 inch wide Aluminum flashing. It was $16 at Ace Hardware. There is enough in one coil for about 6 wheels.

Fabrication consisted of scribing two circles (8 1/8 " and 8 3/8" radii) onto the flashing using a tramel point compas made from Dry Wall circle cutter points, and 1/4 inch square steel rod. The larger circle was used as a guide to cut the flashing out of the stock. After washing the trim ring, it was positioned onto the flashing circle. The trim ring has two notches. The first two 1/2 inch wide tabs were formed by cutting slits into from the flashing circle OD to the inner scribed circle. The first tab was folded up into the first notch. Then the ring carefully alligned to the inner scribed circle before cutting the second tab and folding it up into the second notch. Then 1/2 inch tabs 90 degrees to the first two notches were cut and folded using the scribed circle to keep the trim ring concentric with the flashing circle. At each section of the trim ring more 1/2 inch tabs were cut, bent and folded down. Then 1/2 inch tabs were made halfway between each of those. Eventually, you get to a situation where there is space for about two 1/2 inch tabs between the existing tabs. I cut a V slit halfway between the two tabs at this point, and cut away a V on the outer edges next to the existing tabs. This allowed these two new tabs to fold over flat onto the trim ring, without overlaping the existing fold tabs.

A machinists' hammer was was used to form the tabs onto the trim ring. After manual bending of the tab up, the hard plastic face of the hammer was used to form the tab tight to the circumference of the trim ring, then the rubber face of the hammer used to fold the tab down. The rubber face allows the tab to blend into the variations in the surface of the backside of the trim ring.

After forming the flashing to the trim ring, a hole for the air fittings was made with a drill press, and a forstner bit. Forstner bits work reasonably on aluminum. I used a piece of wood under the flashing so the bit could develop enough pressure to cut the aluminum. This is a little tricky, so be careful if you are not familiar with drill presses.

Next, I used a Demel style tool, with a serated 3/8 inch diamter ball cutter to put weep holes into the trim ring. These were cut from the back of the ring into the 6 depressed areas of the ring. The ring is apparently made from polystyrene, based on the styrene monomer smell when making these weep holes.


The flashing is thin enough that the V shaped spring loaded features of the trim ring still snap solidly into the internal groove of the wheel.

First impressions is that the car seems to be quieter at speed, but that is only anectodotal. Two reasons I wanted to do this was to reduce the rust spotting on the brakes while parked with various kinda of precipation occuring. And second, some road construction has concluded for the winter, resulting in my commute having higher speeds for about 1/3 of the distance. And its winter, and the air is more dense. The impact of cold air on aerodynamics is readily experienced watching planes land at O'hare. Below 10 F, one can hear the planes ripping through the air (it actually sounds pretty neet) over the noise of the engines.

[donee]

Hi again,

More comments. I did not like the racing hub caps, because they are bowed out. This is done to accomodate a wider variety of cars. If you look a the Prius 15" wheel, its concave in, so it does not need this bowing. So a flat hub cap spans over the concave portion without touching any part of the wheel but the outer edge. The flat cap should be better aerodynamically.

[bestmapman]

I thought about doing what you did, but settled on the aero/racing hub caps. They were precut, with holes drilled, and perfect size. It took about 10 minutes per hubcap to intall.

Also they look really good. The circle or outside cut is perfect. I don't think I could have made a clean cut with the tools I had.

This modification gets frequent comments. Almost all the comments are positive. I did get one question on why I needed racing hub caps on a slow car. LOL.

[donee]

Hi Best...,

I cut the flashing with tin snips. I have both straight, right cut and left cut tin snips. Its quite easy to make the cut if one is a little near sighted, take the glasses off, have good lighting with a curve cut tin-snip. And of course, the trim-ring forms the final perfect circle.

It took about an hour to do one of these. The material was an extra 10 minute stop on the way home from grocery shopping.

[donee]

Hi All,

Here is an updated picture. The hole for the valve stem had to be made oblong to accomadate the angle of the valve. With the extender screwed onto the valve, the extender tip was missing the hole.

[bestmapman]

Originally Posted by donee

Hi Best...,

I cut the flashing with tin snips. I have both straight, right cut and left cut tin snips. Its quite easy to make the cut if one is a little near sighted, take the glasses off, have good lighting with a curve cut tin-snip. And of course, the trim-ring forms the final perfect circle.

It took about an hour to do one of these. The material was an extra 10 minute stop on the way home from grocery shopping.

I'll try it when I put them on my other car. Thanks

[Flying White Dutchman]

do you have pictures off the total building of these plates?
i am more a visual guy

[Clubford00]

Hope you dont have a lot of braking to do on your trips. Part of the reason that wheels have "holes" in them is to cool the brakes and dispence of brake dust (brake dust does nasty things to parts)

[donee]

Originally Posted by Clubford00

Hope you dont have a lot of braking to do on your trips. Part of the reason that wheels have "holes" in them is to cool the brakes and dispence of brake dust (brake dust does nasty things to parts)

Hi Clubford,

Take your self a long trip, and bring your Prius home. Then reach into the hole in the wheel and feel the heat with a knuckle. Do not try this on a regular car!

I have done this and gone all the way to touching the disks. They were about 100 F or so. The Prius does not use its friction brakes until 7 mph in normal braking. It uses them only when the battery gets full (long downhills) and panic stops. We do not have long downhills here in Chicagoland. I will be sure to take them off at a rest stop in Nebraska before I proceed into the front range. But around here the disks are getting pitted from non-use.

Most of the braking energy of a Prius goes into the MG2 motor, and onto the batteries. In a regular car where all the slowing energy goes into those disks they run at 300 F or so in metropolitan area driving. My knuckle tells me not to get any closer to 1/2 an inch on those.

[holy_crap]

Nice... Have you noticed an increase in MPG???