Review: Catalyst Carbon Disc Cover
Disc wheels are something of an "all-in" product. Once you've got a disc, you know you're quite serious about this whole triathlon thing. Discs are invariably the fastest wheels around, period. But they do come with a couple inconveniences that other wheels don't offer. The biggest of these is, of course, inflation. I've written entire articles on which pump heads work better with discs. Perhaps equally large an inconvenience is their price tag; discs don't come cheap. Top-end discs will cost you north of $2,000, and even budget discs will usually cost $800 or more. There's long been a popular alternative to the true disc, and it's what's known as the disc cover: a sheet of plastic or composite material that attaches to a standard spoked wheel, essentially creating a disc out of a non-disc.
That's what we're looking at today, specifically the Catalyst wheel cover. At $299, this is still one of the more expensive covers out there (Wheelbuilder.com covers can be had for about $100), but there were a few reasons I wanted to check out the Catalyst. I've owned Wheelbuilder covers before, and wasn't too impressed with the quality. The cover would warp, bulging in the wrong spots and rubbing my derailleur. The Wheelbuilder covers also use screws to hold the cover to your wheel (two sets of plastic screws essentially clamshell the two halves of the cover together). The Catalyst uses a simpler, but perhaps more elegant solution: electrical tape. And rather than regular plastic sheeting, Catalyst uses sheets of 3k carbon fiber for their covers. This doesn't really make them any stiffer, or more aero, but they're definitely pretty. I added my cover to a Flo 90 wheel, which was a good choice because the Flo fairing also uses a 3k weave, so the appearance was a nice match.
Installation is very simple and straightforward: you take off your cassette, add the cover, tape it down on each side, and reinstall the cassette. Done! Some real care is needed, however; if you're not careful, you can easily get the same bulges that screw-type covers are known for, and end up with derailleur rub. But as long as you go slowly, ensure even tension in your tape application, and keep a weather eye for asymmetry in your installation, you'll be fine. The result is a wheel every bit as aero as a true disc, and easily convertible back into your old wheel if/when desired. The converted disc will ride pretty much exactly like your old wheel, and just make you a little more aero in the process. I prefer a tape-down cover over the versions with screw-down sides, as the tape doesn't add more frontal area like the screws do.
There are a couple little bits that aren't quite ideal, however. First off is the construction; Catalyst is using a very thin layup for these covers, I'm guessing just 1 or 2 ply. This makes the cover very flexible, not rigid or stiff in the slightest, and that can make it tough to get a perfectly symmetrical installation done. I still got some slight bulging, despite my best efforts to make it perfect. The other thing about thin ply is that it's too easy to damage when taking off a pump head. As you can see on my cover, there's been a bet of wreckage there.
But for me, the toughest sell is the price. At $300, you're halfway to buying a dedicated Flo Disc. And if you just want to experiment with a disc cover, the Wheelbuilder ones are much cheaper. But it's undeniable that the carbon weave here is pretty, and there will certainly be customers who find that premium worth the price. Probably the prototypical customer here is someone who has a set of nice Zipp hoops (or other premium brand), and wants to keep their premium set on the bike while upgrading to a slightly faster rear. For these people, the Catalyst looks like a very nice option indeed. It completes the disc with an understated and attractive aesthetic, while still costing only a small fraction of what an actual Zipp (or other brand) disc does.