Instructables
Picture of Smooth Wheel Covers on a Budget
I drive a 1994 Geo Metro GE with a 3 cylinder engine. According to the official fuel economy ratings for this car, it should get 38mpg city and 44mpg highway.

I got this car as a gift from a friend. When I went to pick the car up, we had to remove the weeds that had grown up around it and relocate the family of field mice living in the engine compartment. I towed it home and replaced the alternator, a belt, the instrument cluster, and a frozen caliper to get it running.

The gas mileage was pretty good. I got about 35mpg city. I know this car can get more, so I started researching how to improve it. One of the things I found was smooth wheel covers. They are supposed to add around 4% to the fuel economy at highway speeds. This is only a small increase, but with other small changes, it should add up quickly.

I made my own smooth(ish) wheel covers. They look pretty cool and cost me less than $30 to make.
 
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Step 1: Needed Materials

Picture of Needed Materials
tshirt.jpg
hole.jpg
Wheel Covers
I got my wheel covers from ebay for $15. They are just inexpensive, plastic wheel covers.

Fiberglass Resin
This is available at hardware stores, auto parts stores, boating supply stores, and online. I bought mine for $12.

T-shirts x 4
Any t-shirt will do as long as there is a large enough section without any screen-printing. The shirt needs to cover the entire front of the wheel cover with a little extra for securing it in place. I just bought 4 large t-shirts Goodwill for $0.99 each. The third picture shows what happens to the shirt after this project, so don't use one you like wearing; it will be quite drafty.

Mixing Bucket
Any bucket will work, but you probably won't want to use the bucket for anything other than resin mixing after this. Lowe's has inexpensive plastic mixing buckets in various sizes. I bought the single quart size.

Acetone
Acetone is pretty easy to find. You can get it at hardware stores near the paint thinner. This is necessary for clean-up. Between the acetone, bucket, and paintbrush, I spent $12 at Lowe's.

Mixing Stick
Just a stick to mix the resin with. I used a scrap of wood that I had laying around. A paint mixing stick will work. Just make sure to wipe any loose debris from whatever stick you use to keep the resin fairly smooth.

Paintbrush
Any paintbrush will work. If you intend to use the paintbrush more than once, though, get a natural one. The acetone could damage the plastic kind and cause you some frustration.

Razor Knife
Just a basic box knife.

Diagonal Wire Cutters
The wire cutters are useful for the finishing touches, but a tough pair of scissors could also do this job.

Scissors
For cutting the t-shirt.

Cable Ties
The locking, single use kind.

Spray Paint (optional)
For coloring the wheel covers.

Gloves
Keep your hands chemical-free!

Sand Paper
For scuffing the wheel covers. I used a sanding sponge.

5-gallon Bucket (optional)
For a sturdier work surface.
zack2472 years ago
very interesting!
you could even go as far as painting on a design that imitates some nice rims if you wanted.
ive never seen t shirts used in a similar technique as fiberglass, but that seems like it works pretty good, i might almost consider it myself :P
Very nice. I think I'll do this to my spare set of wheel covers. I guess if you want to "round' things out you would use some sort of foam or paper between the shirts and the covers?...ie to make the surfaces look more level.

Thanks!
you could always look for flatter hubcaps/wheel covers too
JackME3 years ago
All I can say is that one of the primary reasons that there is a gaps in wheels is cooling for the brakes which generate a lot of heat under braking (especially when at high speeds on the motorway etc) and then without proper vent can cause the discs to warp and a damage and reduce the braking effectiveness (and fail motoring tests like the MOT in the UK) and will increase you maintenance costs.

A better way to improve the fuel economy would be other tips in the comments such a rev management wheel balancing good servicing etc. However I would also suggest changing your fuel and air filters to better ones as these can provide cleaner air thus a better burn and better efficiency. Also you could try reducing weight etc by taking out anything you do not need, if you have a family this may be tricky however removing rear seats can take off a lot of weight.
Verdann JackME3 years ago
You are making a lot of assumptions here. Such as that it completely blocks the air flow. If these were made professionally, that is possible, in fact I have seen such and they have been around for decades, that are called baby moon hubcaps. There is plenty of airflow from the back and since these don't have perfect seal on the front, there is enough going through there as well.

Also, Downgrading an 'ible cause you don't agree with it is just mean. If the 'ible was badly done or hard to understand is one thing, but doing it because you disagree with the why of it is just wrong.
JackME Verdann3 years ago
Well the material is covered in a solid resin then I would imagine the air flow is severely restricted so i do not think it is an unreasonable assumption. Normally the hot air produced during braking is drawn out by the venturi effect of the vehicle moving forward, thus if the exit is blocked it is harder for the hot air to be removed. As it can be seen from the images, both the wheel and wheel trim has vents for this reason, if the manufacturer thought this was a better way to improve the efficiency then all cars would be sold with solid wheel trims as it would sell more cars however they don't because it has holes for a reason.

I think i know the type you mean, a sort of 50's fashion type? Most of these do also have some ventilation though and the ones that don't as you said 'have been around for decades', i.e. from a period when cars didn't go as fast and the heat dissipation was not as much of an issue or as well documented/understood.

If it appears that I am 'downgrading' the 'ible then that isn't how it was intended, if is well written and easy to understand, however i was just throwing in my 2 cents that there may be better options to improve the fuel economy of the car. I do not disagree with the 'why of it' perhaps just the how of it. And the point of the thread at the end is meant to be a forum for engineers and enthusiasts to discuss projects and their effectiveness otherwise how are we to learn of good ways to further our understanding and improve our projects.
fzumrk3 years ago
Nice job. I am always interested in new ways to fabricate things. I had never thought of using epoxy resin with a cotton t-shirt like that. I would be interested to hear how that construction holds up in this application. Note that painting this is an important step or the resin will break down in the sunlight.
a few years ago, i saw an actual WHOLE CAR BODY made of epoxy impregnated bluejeans! the car had like 35 freaking pockets all over the outside. it was at the same time, one of the coolest looking cars i've ever seen, and the UGLIEST one I've ever seen driving. and I Saw it a couple times over the course of 4 years... so it must last pretty well when done right.
dewrell3 years ago
awesome idea, man. you got my vote!!
siamonsez3 years ago
If it's a stick, you shift points can make a big difference. It might seem like the best mileage would be achieved by shifting early and keeping the rpm low at all times, but depending on how the engine is tuned there is a certain optimal rpm range and if you are shifting before that you are actually wasting fuel because the engine isn't using it as efficiently. For example, my accord hit peak efficiency in the 3,000 to 4,000 range, so even driving around town, when keeping it in second gear until 4,000 rpm might seem like pushing the engine a little for no reason, it is actually more efficient.
Driving fast doesn't make as big an impact on mpg as driving quickly does. In other words, a steady foot on the accelerator is more important than how far down you put it because it's changes in speed that eat up gas.
dimtick3 years ago
hey, good job.
not really digging the dark color, but that's just me. it certainly doesn't detract from the cars overall appearance!
now looking at the pics you've got a lot of rust on the wheel hubs. probably be a good idea to hit those with some rust paint to stop that in it's tracks.
heres a couple more sites:
www.hypermiling.com
http://ecomodder.com/forum/EM-hypermiling-driving-tips-ecodriving.php
they may have good tips for you. i think they're more about driving habits than car mods but everything helps.

I'm assuming you already know this but here's what I do:
a top notch tune up every couple years. getting the engine up to factory specs can really make a difference
getting tire balanced, rotated and wheel alignment a couple times a year.
check tire pressure at least once a month.
i've been using synthetic motor oil which is supposed to be better with high milage cars. to be honest i haven't really notices a difference but i can say that it hasn't hurt it.

keep updating this as you can. i'm interested to hear how your hubs hold up over time and over winter.

good job!
ironsmiter3 years ago
Congratulations on your Gen2 find!
And nice look for the covers! :-)

once you get things tweaked,.. you SHOULD be seeing over 40 city!
Some of it will come from how you drive.
lead feet = poor milage.

Can't wait to see the rest of your geo-related ibles in the future.

You'll want to join in on the fun at
http://autos.groups.yahoo.com/group/MetroSwift/?yguid=153710793
and http://autos.groups.yahoo.com/group/thegeometroclub/?yguid=153710793

There's more information in the archives there than you can shake a stick at.

l8nite3 years ago
I loved my geo metro ! driving the automatic like a stick shift I could get 37mpg around town in traffic ! During non traffic times I could get 40 or better ! I kept my tires over inflated by 10lbs and removed the back seat and any extra weight I could, I also used a synthetic oil. I had over 278,000 miles when the crankshaft broke = (