Wolf Tooth Rear Axle
Many different lengths, an optional protruding protector - and the option to make your bike easily trainer compatible in winter...
Actually, the Bike Industry kicks Apple's Ass
"Bikes are adult-Lego and if you want to keep your old rig running, click some pieces together..."
4 Bikes For Price of 2
Two wheelsets for one bike is not a new idea to enhance bike value - but how about two very different bikes - 27+ & 29'er - with interchangeable wheels?