Hypermiler Flat Hubcaps




Introduction: Hypermiler Flat Hubcaps

About: I have too many projects going on to know where all the little cuts and scratches on my hands come from. Follow me here to catch up on my latest builds.

This simple instructable will show you how to make some quick and dirty hypermiler hubcaps out of recycled coroplast signs. I got my signs for free, once you keep an eye out for it, the corrugated plastic can be found easily.

WARNING! This modification will reduce the rate at which your breaks cool by cleaning up the airlfow around the hubs. This can reduce their effectiveness if they over heat. I experienced it in the mountains when coming down but every vehicle is different so check to make sure they are not burning hot every so often. I also employ hypermiling driving techniques so I use my brakes as little as possible to conserve energy.

The Materials you will need are:

- Enough Coroplast to cover your wheels

- Zipties. At least 8 inches: the longer they are, the easier it will be to install.

The Tools you will need:

- Marker

- Scissors

- Drill and a hole saw that's slightly bigger than the lug nuts

- Spare Tire for tracing purposes

Step 1: Cutting the Circles Out

1. Take your spare tire and lay it over the coroplast. Trace inner metal circles onto the plastic so that they fit in the hub.

2. Try to use the space efficiently; I managed to squeeze two caps into one sign.

3. Cut it out and make sure it fits, trim where needed. A press fit is better as it will help to keep it in place.

Step 2: Cut the Lug Nut Holes and Air Holes

1. With the circle inserted into the spare, flip it around and mark holes where to drill.

2. Drill out the holes for the lug nuts. I used a 1.25 hole saw. This gave me enough clearance to stick a breaker bar in and remove the wheel.

3. With the cap on the wheel, mark out where the inflator valve is and cut out a hole.

Step 3: Install the Caps

1. Drill out holes for the zip ties to go through. Depending on your hubs, the placement of the holes will differ.

2. Thread the zip ties through the holes but do not tighten them. Attach only the first one or two notches in the zip tie. This will give you enough slack to thread the rest of them through.

3. Once all the zip ties are threaded through, tighten them until the hub is snug and won't wiggle.

4. Trim the excess off the zip ties.



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    14 Discussions

    nicely done prototype/test-setup.

    Thought this deserved it's own comment.

    You need to CHECK YOUR BRAKES after driving a while. Some automotive designs use the airflow through car rims to cool brakes and bearings. This cuts off that airflow. Non-contact infrared thermometer($25 or so at a bigbox store) will tell you if you need to add air ducting or not.

    When I did mine('96 geo metro with steel wheels) I used 13" steel pizza pans. And for attachment, I drilled and tapped 1/4-20 holes, and bolted them on using some loctite blue. If i ever went through a lot of downhill, or stop and go city driving, I would stop every hour or so, to make sure the brakes were cold, then back to driving. Never got so hot I couldn't touch them with my bare hand, but better safe than sorry.

    1 reply

    Thanks for the advice! I just got back from a 6,500 mile road trip across the states and it came in handy. When going down mountains I definitely noticed my brakes were acting up so I took the covers off.

    Once they got hot and I came to a stop the heated resin would stick to the breaks where the rotor stopped. After this the breaks would pulse when I came to a stop, a sign of wheel resurfacing needing to be done. Since I couldn't get the done at the time I waited for them to cool and then speed up quick and stopped hard a couple times. This seemed to fix it by cleaning off the discs. Not recommended by any means but I got home.

    Improving the airflow around there will increase efficiency but I will leave that for a later instructable. There is nothing that should be done first, various factors determine when each person can get different modifications done. I had a sheet that fit the wheels and an hour on my hands so I made these.

    Any single aerodynamic improvement on the car probably provides minimal improvements, but altogether with good driving habits I'd be willing to bet it all helps. What other improvements have you made/are you planning on making to your vehicle?

    1 reply

    I have deleted the passenger mirror and also made a front air dam. I also made a wind deflector for the windshield out of coroplast. It just sets into the crease where the hood closes and is held in by pressure.

    I had rear wheel skirts but I am making a V2 of those. On the back of my car I welded on a bench/hauler. I'm going to connect the wheel skirts and under belly pan all the way to the back of the bench for a inverted camback. I also might redo the top of the camper cover to have more of a camback, right now it is very slight.

    since the air flows around a tire this can only effect milage in a bad way since its just adding weight and what's worse is adding weight to the wheel which makes it harder to turn them while this will honestly only effect it in the matter of adding .00000000001 mpg since it coroplast I would so its more dangerous that it might fall off and chase others to crash meaning doing this won't save any money and may cost you 100's of thousands of dollars also this is illegal in some states and countries but this is a cool way to dress up your car I just wouldn't drive on the highway with it I would say off road use only

    3 replies

    I need to contradict ALMOST everything you just said ;-(

    This creates a pocket of air around the wheel and DOES significantly reduce turbulence(which is where the benefit comes from) adding between 1/2 and 1% to fuel milage(as tested by ecomodder and many other groups of fiesta/metro modders) While not noticeable on a 20mpg car, when you start looking at the super high(50+) milage cars it is a measurable increase when averaging tanks of fuel.

    Coroplast is basically plastic cardboard. Hardly likely to cause a crash(though when I tested mine, i made them from steel pizza trays). Even if they do come off(which didn't happen to me over 20K miles) it is no more of a hazard than the plastic hub caps put on standard alloy wheels(infact, the zip ties are probably quite a bit stronger and safer than the plastic tabs holding normal caps in)

    As to being illegal, most car companies selling cheaper wheels use a plastic decorative cover to make their steel wheels LOOK like alloys(at least they used to. see any mid priced car from the 90's or 2000's) I didn't look on the books in every state, but I NEVER had ANY trouble with the law because of my covers.

    Thanks Ironsmiter, it's always good to hear another hyper milers experiences.

    I thought about using pizza trays but I wasn't sure how to attach them and I was looking for as cheap as possible/free. I feel like the pans would have more rotational mass than the coroplast ones but could also be more durable.

    Cwolf13, I don't think they will fall off. I accidentally drove to go get zip ties with the first hubcap just pressed in and it stayed put, the fastest road I traveled on was a 35 mph one.

    Legality? I don't see why it would be illegal. Even if it was the cops most likely wouldn't know the law or have a reason to pull a hyper miler over since they tend to obey the speed limits.

    I would like to make some out of clear coroplast and put LED's in them but that's probably illegal :P

    I hate auto correct lol

    Good idea! Have you done any testing to see what difference these flat hubcaps make? I'd be curious to hear the results.

    Have you considered a full instructable covering all of your hypermiling techniques? I think that would be interesting. Nudge! :)

    2 replies

    Since most of my modifications were done at the same time or with a mixture of city and highway driving its hard to get an accurate reading on efficiency of each mod individually. Over the summer I got a couple tanks that were over 50 mpg but I am about to travel out west (maybe stop by pier 9) so I'll have a larger highway sample to measure off of soon. I would like to post more hypermiling techniques and will do so once I have a little more information on my end to share. Thanks for your interest!