This is really... Odd... Noomad contacted me a while back asking for an address to send something to test/review for citycycling. I'd forgotten about it, till a huge box arrived yesterday.
Basically all you have to do is remove your front wheel and brake, then the frame fits into the fork dropouts with a quick release bar. The axle for the wee wheels is positioned a bit below this, the whole thing having been designed for 26" wheel bikes, so the geometry is maintained.
Costs about £300, which is a bit steep - oh, and they threw in a nice Ortlieb as well...
The wheels lean on a pivoty bar thingy, so both remain in contact when turning (though I tried a few sharp turns and things slid). Going to make sure everything is secure over the weekend, since I had to have a wee workaround with not all the fixings in the box, stick a slick tyre on the back, and take it commuting next week. Expecting some very odd looks...
Untitled by blackpuddinonnabike, on Flickr
Untitled by blackpuddinonnabike, on Flickr
Untitled by blackpuddinonnabike, on Flickr