coroplast "smooth" wheel covers
 

https://lh5.googleusercontent.com/-X...4/IMAG0243.jpg

I've been unable to keep any store-bought hubcaps on my wheels for any length of time - maybe my rims are warped or something.

Because of this, securing wheel covers - smooth or otherwise - to my wheels is a challenge. I've seen some people have some success with velcro, but i'm not totally sold on that, so I decided to go with zipties. the downside is, of course, that they stick out, which I suppose reduces the smooth factor a bit, but I'm hoping it's still an improvement over no wheel covers at all.

Here's my question - Should the edge of my wheel covers ideally be against the tire, or in the inset of the rim (like it is now)?

So far, I've only done one just to make sure it wouldn't rip off while I was driving. So far, it's still there.

I would think against the wheel rim as you have it.

My reasoning is that any tire deflection could jolt the covering, and perhaps result in odd noises/squeaks or in a worse case, sidewall tire wear and or cuts.

I would use the inside of the rim too. Though the rim will deform on speedbumps etc, it will deform far far less than your tire. The coroplast-scuffing-the-tire issue notwithstanding, you'd probably end up with bent covers that would catch air. I think how you have it is great. Now quick, paint something on them. Hello Kitty or something :P

I personally have had the coroplast wheel covers scuff my tires and dig into them over miles of wear and cause damage to my tires. Definitely make the wheel covers the size of the rims and no longer than that.

if you are loseing wheel covers, what type of wheels are thay (steel)

What if you glued another piece of coroplast on top of that one. Then you would have smoothies.

I might even make it a bit smaller than the rim or put a few holes around to release the brake dust.

drill and tap 6mm x 1.o
 

http://farm7.staticflickr.com/6142/5...32ace7ac_b.jpg
drill and tap , 6mm x 1.0

what ever plastic this is it has not cut into the rubber of the tire
at all ,
yet .
http://farm7.staticflickr.com/6143/5...49eee769_b.jpg

Also, you could cut one coil off the spring*, if the spring is cylindrical cross section and has the same pitch such that it will still properly seat on its perch. This would lower the car an inch or more, stiffen the spring rate, but aerodynamically put the wheel/tire further up into the wheel well where it has less exposed frontal area to catch the wind.

Further, as the tire acts as a crude turbine, it throws off 6 vortices, the worst of which is at the upper edge and goes directly against the airflow past the car. You can see this on other cars when driving in the rain on the freeway--the mist turbulence is visible at the upper forward crescent of the wheel well, and can effectively increase the frontal area of the car while buggering the slipstream much more than necessary.

With the wheel/tire further up into the wheel well, less of that upper vortex goes out against the slipstream, as the fender acts as more of a barrier.

Also, the lowered car nose lets less air go under, so less air under means less drag from all that stuff like mufflers, etc..

So, less wheel/tire frontal area + less opposing upper vortex + less under car airflow = less drag.


*This is endlessly debated on the BMW forums, some saying never to do this, others who've actually done it reporting no ill effects if only 1-1.5 coils are cut such that the spring still seats well on its perch, typically the bottom perch. More than that an the spring may dislodge from its perch when unloaded, or you'll have trouble hitting curbs, etc. in the parking lot.