That title is from youtube, where a Deutsche? kid built an aero wheel. I thought that was pretty cool so with a orphan rear wheel I decided to build me a clincher disc. It’s kind of a Zipp - HED hybrid … Zipp uses a foam core, and HEDs are covers over the base Alu rim. This is both an alu rim and foam core.
OK so step one was to prep the wheel and douse the inside area with PU foam to support the outer layer. I had my doubts with the foam application but it turned out promising. Today we shave the expanded foam and sand it smooth, and then decide what to do next. It would be possible to actually just use a xx mil adhesive vinyl if the foam is smooth enough. If not I have 2x2 twill I can use but that will impact weight and make the thing stiff as blazes.
Whomp whomp is good…and you know she drums like that already… stoked about the weight. After going at it with a watermelon knife, body file, and sander I tipped the scales at under 1100g.
I drove into town on my way to get beer and smokes, looked for some sandable sheet “instulation”. Nothing suitable. I wanted a spreadable filler, super light. So I made a water-based mixture using some superlight West filler I had in the shop. Binder, fillers - hope it works! 24 hours to set up before sanding, which should be super easy to do. Why foam? As it expanded, the foam is very, very light. No real structure is necessary, just resistance to blowing out of the spokes. A foam core with a thin vinyl covering should be the lightest possible setup.
I’ve been making DIY discs from spoked wheels for a while. If you use spray foam insulation to
bond a DIY ABS cover to a wheel it’ll do just about as good as far as producing the ominous sound that
an actual disc makes.
I have never gone as far as completely filling in the wheel with spray foam though. What I do is spray it
and smooth it out on both the spokes and the inside of the cover then let it cure for a day or two with some weight added
to the wheel to keep it from expanding.
Any type of plastic or sheeting of thickness 1/16" or more will be too heavy. ABS or HDPE for example - I have both in the shop, too low tech! You won’t see that on aircraft/RC builds.
The wheel builder covers are like 400- 500 grams
The PU foam was really nothing - under 100 grams. I made an error on the filler for fairing in.
This morning on my way to cigarettes and coffee, I got some lightweight spackle and also latex foam. Used some of the both to clean things up. It’s setting up right now.
I also scored some awesome Carbon fiber wrap at Walmart of all places. So should be complete in 24 hours.
She’d done. The lightweight spackle filler worked well. I only sanded one round so it’s a bit lumpy but at 1300g weight is half decent. The wraptech covering is nice to work with but real carbon would have been cool, if using a thin fabric, no need to beef it up. PIA project. I think a better approach might be to start with a really light wheel (eg 750g) and use Balsa sheet on each side before using a real carbon covering.Probably get to the 1000g figure.
That looks pretty cool, but I don’t think I’ll try to replicate it. I need the cover to be removable.
I found that you can buy pvc foamboard in 1mm thickness, but white only. It’s half the weight of solid PVC and should be stiff enough, and then a layer of wrap. This would be similar to removable plastic covers, nothing like yours.
According to the specs I found, both sides should weigh ~470g (380 for the sheets and 90 for the wrap), so it adds a little over 1lb to the weight of the wheel.
