The ones I've seen are like the Swobo except the rear is a rim brake with a front disc. A lot of bikes have/come with disc brake mounting points on the fork, so some just make the change and buy a new wheel or front hub to mount the rotor to....the front is going to do most of the braking anyways and with a disc brake, there won't be as much dirt, mud, leaves, etc clogging up the brake pads. My cousin has a full chain case on his bike to keep the chain and drivetrain cleaner/less maintenance during the winter months.