Have you ridden on it yet? I imagine it's structurally sound because it's still a whole wheel underneath, but does the cover flutter or get sliced by road debris? Would it not be easier and almost as inexpensive to mount a disc cover, especially since you could remove the cover?

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I have not ridden on it yet. I found a guy on the interwebs who did this to a track wheel on his fixie commuter bike that he has been riding for months (?years I can't remember) without any problem). The finish is like a tight drum, I would not expect it to "flutter" in the wind (i'll cover the valve hole with tape).

It weighs essentially nothing. The wheelcovers weigh a ton. They are also not that quick to remove/install as you still have to remove the cassette, line them up, tape them to the spoke, make sure they are not warped, electrical tape around the rim, etc. But mostly, I just didn't like how much weight they added. I weigh <130lbs and the weight of the wheels count for me (also most of the races I do have some climbs/hills).

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Two wheels good. Four wheels bad.

Pretty cool. How much weight did it add? Seems like a decent option for a hilly course or an already lightweight rider. I think a wheelcover normally runs you 400 grams or so. It seems like it would ride like Gerlachs packing tape which he used in races. Keep us updated.

see my answer above.

The monokote film adds essentially no weight. Its very important here because we have hills/climbs and I am a lightweight rider and not very powerful (yet, I am working on it!).

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Two wheels good. Four wheels bad.

I guess my fluttering question was more about air getting in the valve hole, but if that's covered then it wouldn't be a problem. I'm not saying the cover would be easy to remove and put back on; only that you'd have the option. I suppose it wouldn't matter if the DIY wheel was a committed race wheel. Does the cover stretch at all if poked or is it pretty strong? That is to say, can you confidently pack it or put it on a rack without worrying about the cover stretching and becoming loose?

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Good job, but you need to work on your Googly skills!

From 2003: http://lists.topica.com/...rt=d&start=14068

Slowtwitch (with a reference to the above): http://forum.slowtwitch.com/...ing=ultracote;#72883

Why I know a bit about this (probably my third iteration, built on an AC350 wheel):

(photo not loading right now, alas)

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"Go yell at an M&M"

It is a dedicated race wheel. Even when I had the aerojackets on, I essentially never removed them because it was such a pain in the a**. I put my bike on the rack with the training back wheel on because the rack holds the bike by the wheels, and always carry my back race wheel in a case inside the car.

All my races are on courses with laps around, so even if its windy, that's only a portion of the course that I'd have a cross wind. So I don't really plan to remove them at all.

I had removed the aerojackets once for a race because there was a lot of climbing and the weight was an issue.

You can drum on it its so tight. I'll post an update once I ride it, I can even mount my camera to video tape it while riding to see if there is any rippling or such.

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Two wheels good. Four wheels bad.

I tip my hat to you, Doctor. Well done!

Did you happen to figure out what setting is needed to initiate the sealing? Also, how did you determine the right diameter for the circle to be cut out?

Thanks for sharing! That's great.

Are speedos required when racing with a shrink wrap disc wheel? :-)

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Two wheels good. Four wheels bad.

I first cut a 24"x24" square, marked the center, then cut out the center hole for the axel. Then put it over the hole, and marked with a sharpie going around the perimeter in the groove between the tire and the rim - this made it circular but still larger than needed. Then I removed the film, removed its backing, then sealed it around the hub/axel portion first, and then folded it up over itself out of the way into the center of the wheel and applied the glue (cement) to the rim, then glued the edges to the rim, then went around the rim with the exacto knife and cut off the excess that was just loose over the breaking surface. I used the sealing iron around 200C. I used my regular heat gun on its highest temp setting with the low blow power for the shrinking.

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Two wheels good. Four wheels bad.

Looks very cool. Nice job.


However, you may want to read up on weight savings and their impact. You seem to be putting a lot of emphasis on weight reduction for your reason for going this route. I think that if you may find that it isn't really helping you like you think it is. The example cited below shows what a 3.2 lb weight difference makes...a 400g aerojacket cover is .88 lbs

DrTriKat wrote:

I had removed the aerojackets once for a race because there was a lot of climbing and the weight was an issue.

http://www.usatriathlon.org/...e-weight-102113.aspx

You cannot measure the psychological factor of the feeling of lightness.

How much did the rider weigh in that experiment you are quoting? Weight may matter, because even though a smaller rider is dragging less total weight uphill, a larger % of that weight is the dead weight of the bike, and if the smaller rider is female, than the relative power to drag that weight up diminishes, and I would wager that for a much smaller and less powerful rider, the weight savings may be more significant (not to mention that given the cost of materials of <$30 for a membrane disc, the cost/time is awesome compared to a conventional disc wheel). If anyone wants to crunch numbers, I currently weigh 127 lbs, and my 20 min FTP is 136W.

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Two wheels good. Four wheels bad.

From analyticycling.com:

Weight w/bike: 66kg
Slope: 7% (Old La Honda grade)
Power: 136W
How much less weight: .4kg
Distance: 3000m (about how far you'd go in 20min on this grade)
Time savings: 6.11 seconds

Yes, that's all.

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"Go yell at an M&M"

http://analyticcycling.com/ForcesSpeed_Page.html

At 6% grade, your weight and power, and 17.5lb bike, 400g makes a .02 m/s difference, yielding a 72m difference over a hour, or 0.63% of distance traveled. It's about about a watt difference. Not insignificant but not that great.

I'd also venture that you can get a CF cover like the Catalyst, which is an order of magnitude more expensive, but only 50g heavier and most likely significantly more durable (and it shimmers.).

Very curious how the MonoKote holds up to impact from rocks though, seems like it's asking to get torn, and it doesn't look like an easy on-the-road repair.

Considering that the net benefit of a disc on the same order of magnitude, I'm not sure "Yes, that's all" is called for. ;)

The point was that doing this versus the wheel cover just doesn't save that much time. 6 seconds isn't that much time.

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"Go yell at an M&M"

Thanks for that. The CF covers seem great, but I can't at this time justify purchasing a wheelcover that costs more than the wheel you put it on. Just seems silly. But I can probably add some glitter to make mine shimmer as well!

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Two wheels good. Four wheels bad.

Might this also work better for bikes that have cover fitment issues?

And my point was that the net benefit of this is very close to what you're saving by putting a wheel cover on the first place versus a deep rear wheel on a standard course.

Assuming:

1km climb at 5% grade

Rider+bike with disc cover= 66.7kg, CdA=.235, 200W power output
Rider+bike with/out disc cover=66.3kg, CdA=.250, 200W power output

Otherwise the conditions/riders/efficiencies are the same.

Over the 1km climb at 5% grade the 2 riders tie.

On a flat 40k course with 120W output the disc wins by ~1:26.

Even at your weight and power output you're pretty much never going to lose on the disc cover weight vs. aero, and it sounds like your ultra-light version is a best-of-both-worlds solution anyway. Good work!

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I tweet!

That was one of the reasons I did it. I was not happy with the fit of my cover, it had rubbing issues due to the fit (the dishing and diameters are not quite the proper fit for my wheel) and thickness of it.

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Two wheels good. Four wheels bad.

Nice work. As someone who also builds and flies RC planes, I may have to try this.

Just bought an aerojacket but the fit is terrible and has so far been $100 down the drain.

Hi DTK, thanks for your informative post. I've started the wheel film process similar to the
method you used.

A few questions, if I may:

From what you have learned riding the disc, is there anything you would suggest for the
initial process?

Did the glue joint at the rim hold up? As I'm filming aluminum rims, have been experimenting
with different gluing methods and heavy duty adhesives, sprays, double sided tapes, etc.

Has there been any problems due to high and low outside temperatures, as delamination,
film sagging, and access to the air valve?

I cut my film circles and used some heavy duty spray adhesive on the rim and back side of the
film and heated the joint. The blue tape is pulling a film scrap on the angle to the hub. On disc
brake rims, I'll apply only to the brake surface.



Among out group there's a great deal of interest in repeating your method. I plan to make film
kits so my riders can easily repeat the process. Using the lightest aluminum shallow profile rims,
these filmed wheels will be great for climbing and fast on the flat.

Thanks again for getting the wheel rolling and am lookin forward to your riding experience and
thoughts.

Bill