Seems like it would be the fastest and lightest type of wheel. Anyone have any comments?
Ken Lehner made one and posted pics here, back in the T-Rex days (Ah, good times…). Do a search on his posts.
That was the original J disc in the 80’s wasn’t it?
As Paulo mentioned, Ken has built one.
Another option for people who aren’t as handy is a pre cut disc cover from wheelbuilder.com
Thanks. What is Ken Lehner’s Slowtwitch name?
klehner. He actually spends most of his time on the LR these days.
I had a green one, but I didn’t build it. I’ve heard of people making them out of plastic shrink wrap (same stuff you put on the windows and use a hair dryer), but I’d imagine it rips pretty easily.
I have one at home.
Wooden spokes, lenticular
long skewer.
I use it for PIna Coladas
yes and adding dimples takes a long time to 
Thom.
Seems like it would be the fastest and lightest type of wheel. Anyone have any comments?
Given the right wheel, it could be very light indeed. But I preferred reliable (and cheap) and to use my PTap.
You are an ispiration to me. Imagine a Reynolds KOM with a mylar disc.
I use to make these all the time, and I’ve read some of the “home brew” solutions for this. Here is a link on the forum.
After making quite few, I would suggest the following as necessary elaborations to the stuff on the forum:
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You don’t need “yogurt cup inserts” in the monocote/ultracote if you are careful.
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A deep aero rim makes life 100% easier. Don’t do it on a box rim.
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Do NOT use contact cement. What a nightmare. Go to the hobby shop and they will have both supergel glue and/or runny super glue. Then buy the “kicker” solution that makes it instant set.
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A heat gun is absolutely necessary.
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Exacto knife off the extra. Don’t worry if you aren’t perfect, since you can trim the extra.
Once you do 2 or 3, the job will be obvious. The first one, uggghh.
Theo
i’ve always thought about making one of these. I saw in the old thread that the MA3 was a suggested rim to use. I cant seem to find that one out there anymore. Is there something else in the same price point that works as well.
Another stupid question… I curently only have a road bike. Would there be much gain from a disc even though the cockpit isn’t all that aero?
I’m thinking Lew rims are the ones to use.
Okay, I went down to the garage and dug out one of my old wheels. I’ve move multiple times, and the cover was half ripped off on the one I found, which shows some construction details.
Link
The above photo is the hub hole, just poking through the monocote. Again, I never had an real issues just cutting a hole in the monocote, but some will laminate in a yogurt lids or something to protect the monocote.
Link
Here’s an inside photo.
Now, I normally just raced on these wheels, so I covered the stem hole with clear packing tape. If I remember right, I would use a thin pump head and only have a hole in one side. However, if I remember right, this was the biggest pain of the wheel, since you had to handle the hole pretty gingerly.
Link
I’ve been running HED3 for 8 years, but in retrospect, I’ve been thinking about getting a Powertap, and this (and others have said) is the perfect union.
I did have the normal “wheel covers” (multiple types, and at least one like the ones sold by CO Cyclist). They all added a pound of rotating weight to the bike and felt heavy. The monokote cover is much, much lighter. Once you’ve done a wheel or two, you can really shrink the monocote, and if you tap the wheel it sounds like a drum head, or super tight.
The bigger thing to to make sure you’ve built a super tight wheel, without spoke twist. A good wheel, ala Jobst Brandt’s advice, simply doesn’t become untrued. (The rim may dent, but that is another problem)
I wish somebody would actually take one of these into a wind tunnel and try it out. I think JDisk had a good idea, but the company fell for other reasons that just having a bad product idea.
It always felt much less sloppy than the wheel covers, and intuitively it should test very well.
I miss my J-disc. Was a really nice wheel. Used a hair dryer to tighten the mylar when is became loose.
just doing a google search brought up this page:
http://www.wisil.recumbents.com/wisil/ariail/fabric_wheeldisks.htm
Interesting idea of how to attach it to the rim to keep it removeable. He used ripstop nylon, but I’m sure it could be done with the mylar stuff. I wonder how much weight the added fiberglass would add.
I made one and posted it on here. I don’t know how long the post or pictures last though. It was pretty easy to do and cheap.
http://forum.slowtwitch.com/gforum.cgi?post=223696;search_string=home%20made;#223696
I made one before. It was pretty easy, but I’m not sure I was convinced it ‘worked’. I bought heat shrink mylar from a hobby store and used plastic caps to make holes for the hubs and a square plastic cap for the valve. It ironed out pretty nicely, but I didn’t see much improvement in my cycling with it, although I didn’t really do any field testing.
EDIT: Added the picture. I also used ultrcote mylar. And the blotches you see are from rain I believe, but I don’t really remember (it was a while ago). The blue waves were my attempt at being creative. They looked better in person ;-).