Found: Gear Clamp Easily Converts Standard Freehub to Single Speed
Looking for a simple solution to convert your standard rear hub to a single speed?
Sure, you could use a bunch of spacers at about 40g of weight. Or, you could use the Gear Clamp by Christopher Burdick and cut that by more than half. The pair weigh in at just 18g, but the bigger benefit is that you can precisely position the cog anywhere on the freehub body.
Jump past the break for more details, pricing and photos…
The Gear Clamp is made in the USA and costs $29.95. They’re made to be run with 16 tooth cogs and larger, but Chris says if you want to run a 15T or smaller, you’d simply put one spacer on either side of the cog, then the clamps.
He hasn’t tested them on Campy, but like any good small manufacturer, if there’s enough demand, he can make some for Campagnolo hubs and even make other colors.